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Glossary of technical terms for the use of metallurgical engineers   Terms starting with alphabet ‘B’

• satyendra
• September 12, 2024
• 34 Comments
• Terms starting with 'B",

Glossary of technical terms for the use of metallurgical engineers

Terms starting with alphabet ‘B’

Babbitt metal, Babbitt – It is a non-ferrous bearing alloy originated by Isaac Babbitt in 1839. Presently, the term includes several tin-base alloys consisting mainly of different quantities of copper, antimony, tin, and lead. Lead-base Babbitt metals are also used.

Babbitting – It is a process by which relatively soft metals are bonded chemically or mechanically to a stronger shell or stiffener, which supports the weight and torsion of a rotating, oscillating, or sliding shaft. The babbitt, being softer than the shaft and having excellent anti-frictional qualities, prevents galling and / or scoring of the shaft over long periods of use.

Back bead – It is a weld bead resulting from a back weld pass.

Back draft – It is a reverse taper on a casting pattern or a forging which prevents the pattern or forged stock from being removed from the cavity. In blast furnace, back draft is during periods when the furnace is shut down it is connected to a back drafting stack which produces a reversal of flow of the gaseous products in the furnace which are vented through the stack.

Back-drive – It is a component used in reverse to obtain its input from its output. This extends to several concepts and systems from thought based to practical mechanical applications.

Back-end condition – It is a condition which is occurring in the last metal to be extruded. It is a result of the oxidized surface of the billet feeding into the extrusion.

Back-end defect It is a defect found in extruded products because of incorrect extrusion procedures at the mill.

Back emission – It is the electrical breakdown of air resulting from an excessive charge buildup in porcelain enamel powder film during powder application. This reaction is because of the self-limiting characteristic of electrostatic powders.

Backfill – It consists of placing the material in a drilled hole for filling space around anodes, vent pipe, and buried components of a cathodic protection system. In mining, it is the waste material used to fill the void created by mining an ore-body.

Backfire – It is the momentary recession of the flame into the welding tip or cutting tip followed by immediate reappearance or complete extinction of the flame.

Back gouging – It is the removal of weld metal and base metal from the other side of a partially welded joint to facilitate complete fusion and complete joint penetration upon subsequent welding from that side.

Background noise – It is a sound other than the sound being monitored (primary sound). Background noise is a form of noise pollution or interference. Background noise is an important concept in setting noise levels.

Background signal – It is an observed signal, such as a current or electro-magnetic wave, which is not generated by the object being measured or studied. It is an extraneous signal which can be confused with the phenomenon being observed or measured.

Back-hand welding – It is a welding technique in which the welding torch or gun is directed opposite to the progress of welding.

Backing – In grinding, it is the material (paper, cloth, or fiber) which serves as the base for coated abrasives. In welding, it is a material placed under or behind a joint for improving the quality of the weld at the root. It can be a metal backing ring or strip, a pass of weld metal, or a non-metal such as carbon, granular flux, or a protective gas. In plain bearings, it is that part of the bearing to which the bearing alloy is attached, normally by a metallurgical bond.

Backing board -It is a second bottom board on which moulds are opened.

Backing filler metal – It is a non-standard term for consumable insert.

Backing film – It is a film used as auxiliary support for the thin replica or sample-supporting film. It is a weld bead resulting from a backing pass.

Backing pass – It is a weld pass made for a backing weld.

Backing ring – It is the backing in the form of a ring, normally used in the welding of pipe.

Backing shoe – It is a non-consumable backing device used in electroslag and electro gas welding.

Backing weld – It is backing in the form of a weld.

Backlash – Backlash in gears is a typical cause of dead space. Backlash is normally experienced in gear-sets used to convert the translational motion to rotational motion.

Back-off – It is a rapid withdrawal of a grinding wheel or cutting tool from contact with a work-piece.

Back pressure – It is the resistance of a material, because of its viscosity, to continued flow when mould is closing.

Back reflection – It is the diffraction of x-rays at a Bragg angle approaching 90-degree.

Back relief – The back relief area of a wire drawing die is designed to strengthen the exit of the die and prevent breakage of the insert.

Back ring – It is a split or multi-segment ring in a circumferential seal assembly used for restricting axial leakage flow.

Back seat – It is a shoulder on the stem of a gate valve which seals against a mating surface inside the bonnet to permit replacement, under pressure of stem seals or packing.

Back-step sequence -It is a longitudinal sequence in which weld passes are made in the direction opposite to the progress of welding.

Back-to-back ring seal – It is an adaptation of the simple ring seal which employs two identical elements loaded axially by a spring placed between the rings. The spring forces the elements against mating rings on either side.

Backup battery – It provides power to a system when the primary source of power is unavailable. Backup batteries range from small single cells to retain clock time and date in computers, up to large battery room facilities which power uninterruptible power supply systems for large data centres. Small backup batteries can be primary cells. Rechargeable backup batteries are kept charged by the prime power supply.

Back-up rolls – These are the roll which support the work rolls and are the largest and heaviest rolls used in rolling mills. These rolls can support intermediate rolls for the purpose of avoiding deflection of the work rolls. These rolls affect the yield and quality of the plate and strip rolling mill.

Backup storage – It consists of the storage device and the software which manages the stored data. The storage device can be physical, in the form of a desktop or portable external hard drive or series of drives, or it can be network-based. Network storage allows remote storage, access, and retrieval of critical content.

Backward inclined fan – This fan can operate with changing static pressure (as this does not overload the motor). These fans are suitable when system behaviour at high air flow is uncertain. They are suitable for forced-draft services. Flat bladed fans are more robust while the curved blades fans are more efficient (exceeding 85 %). Thin air foil blades fans are most efficient. These fans are not suitable for dirty air streams (as fan shape promotes accumulation of dust). Air foil blades fans are less stable because of staff as they rely on the lift created by each blade. Thin air foil blades fans are subject to erosion.

Backward integration – It is a form of vertical integration in which an organization expands its role to fulfill tasks formerly completed by other organizations up the supply chain. In other words, backward integration is when the organization acquires or merges another organization which supplies the products or services needed for the production of its products. Organizations pursue backward integration with the expectation that the process is going to result in cost savings, increased revenues, and improved efficiency in the production process. Organizations also use backward integration as a way of gaining competitive advantage and creating barriers to entry to new industry entrants.

Backward pass – It is the process of moving backward through a project from finish to start to determine the latest start and finish times for the activities of the project.

Back weld – It is a weld made at the back of a single-groove weld.

Bacteria – It is a diverse group of micro-organisms which occur naturally in aquatic environments. Bacteria which occur naturally in surface water normally are not harmful to humans, but pathogenic bacteria can be introduced into surface waters from waste-water, particularly from sewage effluents.

Baffle – It is a plate or wall for deflecting gases or liquids. Baffles are flow-directing or obstructing vanes or panels used to direct a flow of liquid or gas. They are used in some industrial process vessels (tanks), such as shell and tube heat exchangers, chemical reactors, and static mixers.

Baffle tile– It is a tile for deflecting gases.

Baffle type collector – It is a device in gas paths utilizing baffles so arranged as to deflect dust particles out of the gas stream.

Bag filter – It is a device containing one or more cloth bags for recovering particles from the dust laden gas or air which is blown through it.

Bagging – It is applying an impermeable layer of film over an uncured part and sealing the edges so that a vacuum can be drawn.

Bag-house – It is an air pollutant control device which is used to trap particles by filtering gas streams through large cloth or fiberglass bags.

Bag moulding – It is a method of moulding or laminating which involves the application of fluid pressure, normally by means of air, steam, water, or vacuum, to a flexible barrier material which transmits the pressure to the material being moulded or bonded.

Bag side – It is the side of the part which is cured against the vacuum bag.

Bag type collector – It is a filter in which the cloth filtering medium is made in the form of cylindrical bags.

Bag wall – It is a protective wall within a kiln around individual fire boxes (flash wall).

Bainite – It is a Lath-type metastable aggregate consisting of dispersed carbide in ferrite resulting from the transformation of austenite at temperatures below the pearlite range but above Ms temperature. Its appearance is in the form of relatively coarse ferrite laths between which carbides are precipitated as platelets if formed in the upper part of the bainite transformation range and acicular, resembling tempered martensite, if formed in the lower part. Bainite is normally classified as upper bainite or lower bainite. Upper bainite forms martensite isothermally or during continuous cooling at temperatures just below those which produce bainite. Lower bainite forms at still lower temperatures, down to the Ms temperature or slightly below in certain cases.

Bainitic hardening – It is quench-hardening treatment resulting principally in the formation of bainite.

Bake – It is to remove gases from a powder at low temperature. It is also to heat treat a compacted powder mixture of a metal and polymer at the curing temperature.

Baked core – It is a core which has been heated through sufficient time and temperature for producing the desired physical properties attainable from its oxidizing or thermal-setting binders.

Bake hardening steels – Bake hardening steels are cold-rolled, low-carbon sheet steel used for automotive body panel applications. They are so constituted that after press forming and baking through the paint curing process they age and has good stamping and strength characteristics. They have good formability which is combined with added stiffness in the finished component. This is desirable in an automotive body panel in which enhanced dent resistance is a requirement.

Bakelite – It is a proprietary name for a phenolic thermosetting resin used as a plastic mounting material for metallographic samples.

Baking – It is heating to a low temperature in order to remove gases. It is curing or hardening surface coatings such as paints by exposure to heat. It is also heating to drive off moisture, as in baking of sand cores after moulding.

Balanced construction – It consists of equal parts of warp and fill in fibre fabric. It is the construction in which reactions to tension and compression loads result in extension or compression deformations only and in which flexural loads produce pure bending of equal magnitude in axial and lateral directions.

Balanced design – In filament-wound reinforced plastics, it is a winding pattern so designed that the stresses in all filaments are equal.

Balanced in-plane contour – In a filament- wound part, it is a head contour in which the filaments are oriented within a plane and the radii of curvature are adjusted to balance the stresses along the filaments with the pressure loading.

Balanced laminate – It is a composite laminate in which all laminae at angles other than 0-degree and 90-degree occur only in +/- pairs (not necessarily adjacent).

Balanced scorecard (BSC) – It is a strategic planning and management tool which is extensively used by the organizations to align organizational activities to the vision and strategy of the organization, improve internal and external communications, and monitor organization performance against strategic goals. The concept is a performance measurement framework which has added strategic non-financial performance measures to traditional financial metrics for providing management of the organization a balanced view of the organizational performance.

Balanced twist – It is an arrangement of twists in a combination of two or more strands which does not cause kinking or twisting on themselves when the yarn produced is held in the form of an open loop.

Balance sheet – It is a summary of the financial balances of an organization. A balance sheet is frequently described as a snapshot of the financial condition of the organization.

Balancing machine – It a measuring tool which is used for balancing rotating machine parts such as rotors for electric motors, fans, turbines, disc brakes, disc drives, propellers and pumps.

Balancing refractory lining wear – It means that the lining for a furnace is to be designed by refractory type and / or thickness so that no materials are wasted at the end of the furnace campaign, i.e., so that all areas of the furnace are worn to a stopping point such as the safety lining at the same time.

Bale – A bale is a compact, easy-to-move bundle of a steel scrap. Bales are formed in different shapes by a machine called a baler, and wrapped in straps so they can be efficiently transported or stored.

Baler, baling machine – It is a piece of equipment used to compress the scrap material into compact bales. This makes it easy to handle, store, and transport.

Baling presses – These are essential tools for managing large quantities of loose scrap efficiently. These machines, whether vertical balers or horizontal balers, are designed to compress the scrap material into compact, manageable bales, considerably reducing the volume of material. The bale chamber is where this transformation occurs, with the hydraulic cylinder applying the necessary force to compress the material.

Ball – It is the spherical closure element (obturator) of a ball valve.

Ballast – A ballast refers to the layer of crushed stones or rocks which is laid on the track bed to provide stability, drainage, and support to the railway tracks. It serves as a foundation for the tracks, keeping them aligned, maintaining proper drainage, and distributing the loads exerted by trains.

Ball bearings – These bearings use balls which roll on conformal raceways on the inner and outer rings (races) outer and inner surfaces respectively. By having the raceway closely conform to the ball, rather than rolling on a pure cylinder, orders of magnitude greater load capacities are obtained. There are several different types of ball bearings, but in general, when the term ball bearing is used, it is normally referred to a deep-groove radial bearing. Ball bearings are extremely common since they can handle both radial and thrust loads. In these bearings rolling function is provided by a ball. They are low friction high speed bearings meant for light to medium loading.

Ball burnishing – It is removing burrs and polishing small stampings and small machined parts by tumbling in the presence of metal balls.

Ball-cock valves – These valves are used in controlling levels in tanks. The valve is connected to a float in the tank using a lever. When the level in the tank rises, the float rises and forces the valve to be shut at the maximum level of the tank allowed. Ball-cock valves are used mostly in water tanks and other low‐risk areas within a certain process.

Ball complement – It is the number of balls contained in a ball bearing.

Ball detent – It is a simple mechanical arrangement which is used to hold a moving part in a temporarily fixed position relative to another part. Normally the moving parts slide with respect to each other, or one part rotates within the other.

Ball indented bearing – It is a bearing with surface indentations serving as lubricant reservoirs.

Balling up – It is the formation of globules of molten brazing filler metal or flux because of the lack of wetting of the base metal.

Ball mill – It is a machine consisting of a rotating hollow cylinder partly filled with metal balls (normally hardened steel or white cast iron) or sometimes pebbles; used to pulverize crushed ores or other substances such as pigments or ceramics.

Ball milling – It is a method of grinding and mixing material, with or without liquid, in a rotating cylinder or conical mill partially filled with grinding media such as balls or pebbles.

Ball screw – It is a mechanical linear actuator which translates rotational motion to linear motion with little friction. A threaded shaft provides a helical raceway for ball bearings which act as a precision screw. As well as being able to apply or withstand high thrust loads, they can do so with minimum internal friction.

Ball sizing – It is sizing and finishing a hole by forcing a ball of suitable size, finish, and hardness through the hole or by using a burnishing bar or broach consisting of a series of spherical lands of gradually increasing size coaxially arranged. It is also called ball burnishing, and sometimes ball broaching.

Ball spline – It is a special type of linear motion bearing which is used to provide nearly frictionless linear motion while allowing the member to transmit torque simultaneously. There are grooves ground along the length of the shaft (hence forming splines) for the recirculating ground balls to run inside. The outer shell which houses the balls is called a nut rather than a bushing, but is not a nut in the traditional sense, since it is not free to rotate about the shaft, but is free to travel up and down the shaft.

Ball thrust bearings – These bearings are designed to handle exclusively thrust loads in low-speed low-weight applications.

Ball valve – A ball valve is a valve with a spherical disc which is the part of the valve controlling the flow through it. The sphere has a hole, or port, through the middle so that when the port is in line with both ends of the valve, flow occurs. When the valve is closed, the hole is perpendicular to the ends of the valve, and flow is blocked. There are four types of ball valves, namely (i) full port ball valve, (ii) reduced port ball valve, (iii) V-port ball valve, and (iv) trunnion ball.

Band density – In filament winding, it is the quantity of fiberglass reinforcement per centimeter of band width, expressed as strands (or filaments) per centimeter.

Band thickness – In filament winding, it is the thickness of the reinforcement as it is applied to the mandrel.

Band width – In filament winding, it is the width of the reinforcement as it is applied to the mandrel.

Banded iron formation – It is a bedded deposit of iron minerals.

Banded structure – It is a segregated structure consisting of alternating nearly parallel bands of different composition, typically aligned in the direction of primary hot working.

Banding – It is Inhomogeneous distribution of alloying elements or phases aligned in filaments or plates parallel to the direction of working. In the hot rolled low alloy steels, pearlite and ferrite are arranged in the wide layers. In longitudinal section, this arrangement is visible as a banded structure. Banding is the defect observed in the wire rod during the time of cracking where in the inter-ferrite distance increases with thickening of the pearlitic deposition in the rod. It can be detected as the lamellar streaks of ferrite and pearlite observed under microscope. It occurs due to the slow cooling on cooling conveyor. Banding can lead to upset failure.

Banding, product packing – Banding is used to unitize a product for shipment. Steel, plastic and cord banding is available along with seals and buckle and strapping tools.

Band mark – It is an indentation in carbon steel or strip caused by external pressure on the packaging band around cut lengths or coils. It can occur in handling, transit, or storage.

Band of segregation – It is also known as banding and has been found because of the abrupt changes in temperature profile across the mushy zone during the early stages of solidification, which may be caused by thermal pulses from convection or changes in heat transfer due to air gap formation (unsteady heat flow). If the ingot does break free from the mould, solute-rich bands can be formed due to the remelting of solid and expansion of the mushy zone. Changes in conditions which lead to acceleration of the liquidus isotherm toward the ingot centre gives a similar result. Solute-poor bands are formed when the mushy zone size is reduced.

Bands – These are hot-rolled steel strip, normally produced for rerolling into thinner sheet or strip.

Band saw – A band saw is a power saw with a long, sharp blade consisting of a continuous band of toothed metal stretched between two or more wheels to cut material. Band saws are used principally in woodworking, metalworking, and lumbering, but can cut a variety of materials.

Band width – It is the range of frequencies over which a system generates or uses significant signal power.

Banking –In case of banking of the blast furnace, the blast is taken off, the blow pipes are dropped, and the tuyere openings are plugged with clay to prevent air from drafting through. Hence, the heat of the hearth is preserved and the blast furnace can be returned to operation with a minimum effort. Banking of the blast furnace is adapted for short outages. The banking is also resorted to as an emergency measure when some unforeseen event needs a shutdown of the blast furnace. Banking operation is carried out as a planned event. Preparations are made depending upon the length of the banking time anticipated.

Bank sand – It is sedimentary deposits, normally containing less than 5 % clay, occurring in banks or pits. The sand is used in core making and in synthetic moulding sands

Bar – It is a section hot rolled from a billet to a form, such as round, hexagonal, octagonal, square, or rectangular, with sharp or rounded corners or edges and a cross-sectional area of less than 105 square centimeters. It is a solid section which is long in relationship to its cross-sectional dimensions, having a completely symmetrical cross section and a width or greatest distance between parallel faces of 9.5 millimeters. Bar is also a metric unit of pressure. It is not a SI unit, but it is accepted for use with the SI (The International System of Units). 1 bar = 14.504 psi = 0.1 MPa.

Bar changer – Bar changer is a robotic machine used to handle and install rods or soaking bars into the taphole drill. A bar changer normally incorporates a bar magazine containing different diameters of bar or rod. The arm of the moving carriage can load a bar from the magazine into the drill chuck, or remove a spent bar from the drill after use.

Bar chart – It is also known as bar graph. It is a diagram for showing the frequencies of a variable which is categorical or discrete. The lengths of the bars are proportional to the frequencies or the percentages. The widths of the bars are be equal. It is also a diagrammed calendar schedule of activities’ start and end dates in logical order.

Bar code – It is an identification symbol where the value is encoded in a sequence of high contrast, rectangular bars and spaces. The relative widths of these bars and spaces contain the information. Identification is by visual or electronic means.

Bar, cold-finished – It is the bar brought to final dimensions by cold work to get improved surface finish and dimensional tolerances.

Bar, cold-finished extruded – It is the cold-finished bar produced from extruded bar.

Bar, cold-finished rolled – It the cold-finished bar produced from rolled bar.

Barcol hardness – It is a hardness value got by measuring the resistance to penetration of a sharp steel point under a spring load. The instrument, called the Barcol impressor, gives a direct reading on a 0 to 100 scale. The hardness value is frequently used as a measure of the degree of cure of a plastic.

Barcol hardness test – Barcol hardness is a method by which a hardness value obtained by measuring the resistance to penetration of a sharp steel point under a spring load. The instrument, called the Barcol impressor, gives a direct reading on a 0 to 100 scale. Barcol hardness test method is used to determine the hardness of both reinforced and non-reinforced rigid plastics.

Bare electrode – It is a filler metal electrode consisting of a single metal or alloy which has been produced into a wire, strip, or bar form and which has had no coating or covering applied to it other than that which was incidental to its manufacture or preservation.

Bare glass – It is a glass, such as yarns, rovings, and fabrics, from which the sizing or finish has been removed. It is also that glass which is before the application of sizing or finish.

Bare spots – These are the defects on the steel surface which have not galvanized because of poor design or poor pre-treatment.

Bar, extruded – It is the bar brought to final dimensions by hot extruding.

Bar folder – It is a machine in which a folding bar or wing is used to bend a metal sheet whose edge is clamped between the upper folding leaf and the lower stationary jaw into a narrow, sharp, close, and accurate fold along the edge. It is also capable of making rounded folds such as those used in wiring. A universal folder is more versatile in that it is limited to width only by the dimensions of the sheet.

Bar grinding mill – Ball grinding mill is same kind of mill as rod mill, except that it is filled with balls instead of rods. Since balls have higher ratio of surface area than rods, they are more suitable for fine grinding. Balls are also lighter, so the kinetic energy of a single dropping ball is smaller than a rod. The lining material is of great importance as there is a significant quantity of wear taking place because of the action of the steel balls.

Barium – It is chemically similar to calcium and occurs as a very basic oxide in some iron and manganese ores. It is not reduced in the blast furnace but becomes part of the slag, increasing the slag basicity. It can cause difficulty in controlling the metal composition if the operator is not aware of its presence.

Bark – It is the decarburized layer just beneath the scale which results from heating steel in an oxidizing atmosphere.

Barkhausen effect – It is the sequence of abrupt changes in magnetic induction occurring when the magnetizing force acting on a ferro-magnetic specimen is varied.

Bar mill – This rolling mill is used for the rolling of the bar products and reinforcement bars. Bar products include rounds, flats, squares, angles, tees, channels, and beams etc. There are two types of bar mills namely (i) merchant bar mill for rolling merchant products, and (ii) special bar quality mill for rolling special bar quality steels.

Barn – It is a unit of area equal to 10 square centimeters to 24 square centimeters used in specifying nuclear cross sections.

Barometer – It is an instrument which is used to measure air pressure.

Barometric pressure – It is the atmospheric pressure as determined by a barometer normally expressed in millimeter of mercury.

Barrel burnishing – It is the smoothing of surfaces by means of tumbling the work in rotating barrels in the presence of metallic or ceramic shot, and in the absence of abrasive. In ball burnishing, the shot consists of hardened steel balls.

Barrel cleaning – It is the mechanical or electrolytic cleaning of metal in rotating equipment.

Barrel finishing – It is improving the surface finish of work-pieces by processing them in rotating equipment along with abrasive particles which can be suspended in a liquid. The barrel is normally loaded around 60 % full with a mixture of parts, media, compound, and water.

Barreling – It is the convexity of the surfaces of cylindrical or conical bodies, frequently produced unintentionally during upsetting or as a natural consequence during compression testing.

Barrel plating – It is plating articles in a rotating container, normally a perforated cylinder which operates at least partially submerged in a solution.

Barrel reclaimer – Barrel drum reclaimer is used when robust systems are needed for the high-performance blending and reclaiming of bulk materials, especially when the materials are semi-hard to hard. As in the case of the bridge type scraper reclaimer, a barrel type reclaimer is used where reclaiming is to be carried out from the face of a stockpile for blending. The barrel reclaimer comprises of a bridge spanning the stockpile which is supported on ‘A’ shaped frames at each side. These frames are carried on motor-driven bogies which run on rails laid on each side of the pile.

Barren solution – It is a solution in hydro-metallurgical treatment from which all possible valuable constituents have been removed. It is normally recycled back to plant for reuse in process.

Barrier -It is a separating device to insulate or isolate electrical circuits. It is also the separating device in gas / hydraulic systems.

Barrier coat – It is an exterior coating applied to a composite filament-wound structure to provide protection. In fuel tanks, a coating applied to the inside of the tank to prevent fuel from permeating the side wall.

Barrier film – It is the layer of film used during cure to permit removal of air and volatiles from a reinforced plastic or a composite lay-up while minimizing resin loss.

Barrier layer – In anodizing aluminum, it is the thin, pore-free, semiconducting aluminum oxide region nearest the metal surface and distinct from the main anodic oxide coating, which has a pore structure.

Barrier plastics – It is a general term which is applied to a group of lightweight, transparent, impact-resistant plastics, normally rigid copolymers of high acrylonitrile content. Barrier plastics are normally characterized by gas, aroma, and flavour barrier characteristics approaching those of metal and glass.

Barrier protection – It is the protection provided by inhibiting oxidation (rust) by an insoluble top coating such as zinc, which isolates steel from any electrolytes which assist the corrosion process.

Bar, rolled – It is the bar brought to final dimensions by hot rolling.

Bars – Bars are the hot rolled long products which also includes the flat bars. The nomenclature of bar normally does not include reinforcement bars which are normally used for the concrete reinforcement. The classification hot rolled bars normally include (i) rounds which are bars having a circular cross-section with the diameter of at least 8 mm, (ii) squares, hexagons and octagons which are bars having a square, hexagonal or octagonal cross-section with the side being normally of at least 8 mm for square bars and of  14 mm for hexagonal and octagonal bars, and (iii) flats which are bars having a rectangular cross-section rolled on the four faces with the thickness of normally at least 5 mm and the width not higher than 150 mm.

Bar, saw-plate -It is the bar brought to final thickness by hot or cold rolling and to final width by sawing.

Bar turning – It involves machining a metal bar into a smaller diameter.

Basal plane – It is the plane of a hexagonal or tetragonal crystal perpendicular to the axis of highest symmetry. Its Miller indices are (001).

Basalt – It is an extrusive volcanic rock composed primarily of plagioclase, pyroxene and some olivine.

Base – It is a chemical substance which yields hydroxyl ions (OH) when dissolved in water. A base accepts a proton and has a pH above 7.0. A common example is sodium hydroxide (NaOH). It is also the surface on which a single-point tool rests when held in a tool post, which is also known as heel. In forging, anvil is also sometime being referred as base.

Base box, general – It is an agreed-upon unit of area used mainly in packaging applications. One common base box is 20.232 square metre originally composed of 112 rectangular sheets, each of 356 millimeters by 508 millimeters.

Baseline data – It is an initial set of observations or measurements used for comparison. It is a starting point in an investigative study.

Base-line performance – It is the benchmark against which different measurements are compared over time.

Base-line technique – It is a method for measurement of absorption peaks for quantitative analysis of chemical compounds in which a base line is drawn tangent to the spectrum background; the distance from the base line to the absorption peak is the absorbance due to the sample under study.

Base load – Base load is the term applied to that portion of a station or boiler load which is practically constant for long periods. It is also the constant quantity of power needed to meet a continuous minimum electricity demand.

Base material – It is the material to be welded, brazed, soldered, or cut.

Base metal – It is the metal present in the largest proportion in an alloy. For example, brass is a copper-base alloy. It is also the metal to be brazed, cut, soldered, or welded. After welding, it is that part of the metal which has not melted. It is also a metal which readily oxidizes or which dissolves to form ions.

Base oil – It comprises the largest component of grease, representing 80 % to 97 % by weight. The choice of base fluid can be mineral oil, synthetic oil, or any other fluid which provides lubricating properties. The base oil portion of the grease performs the actual lubrication except in very slow or oscillating applications. The same rules which are applied to determine proper viscosity grade in a fluid lubricant, apply to the selection of the base oil portion of lubricating grease.

Base stock – Base stocks are refined from crude oil to obtain products with the best lubricating properties. Base stocks generally make up 80 % to 95 % of typical engine oil with 5 % of additives. Base stock is used to describe plain mineral oil. The physical properties of the lubricating oil depend on its base stock. In most cases it is chemically inert. There are three sources of base stock namely (i) biological, (ii) mineral, and (ii) synthetic. The oils manufactured from these sources show different properties and they are suitable for different applications.

Basic bottom and lining – These are the inner bottom and the lining of a melting furnace, consisting of materials such as crushed burned dolomite, magnesite, magnesite bricks, or basic slag which give a basic reaction at the operating temperature.

Basic dynamic load capacity – In bearing, it is the radial load which a rolling-element bearing can support for a rating life of one million revolutions (500 hours at 33 revolutions per minute) .

Basic grade pig iron – It has less than 1 % silicon, under 1 % manganese, and trace quantities of sulphur and phosphorous. This type of pig iron is mainly used for steel making. There are several grades specified in different standards based on silicon and manganese content of the pig iron.

Basicity – Basicity of a molecule is a measure of its ability to accept a proton (H+) to form a stable product. basicity of water is indicated by pH, which is formally defined as the negative logarithm of the hydrogen ion concentration.

Basic load rating – It is the radial load which a ball bearing can withstand for one million revolutions of the inner ring. It is to be noted that the value of the basic load rating depends on bearing type, bearing geometry, accuracy of fabrication, and bearing material.

Basic NMR frequency – It is the frequency, measured in hertz, of the oscillating magnetic field applied to induce transitions between nuclear magnetic energy levels.

Basic oxygen furnace – It is a large tiltable vessel lined with basic refractory material. It is a type of furnace for modern steelmaking. After the furnace is charged with hot metal (molten pig iron), which can comprise up to 90 % of the charge, scrap steel, and fluxes, a lance is brought down near the surface of the molten metal and a jet of high-velocity oxygen impinges on the metal. The oxygen reacts with carbon and other impurities in the steel to form liquid compounds that dissolve in the slag and gases that escape from the top of the vessel.

Basic oxygen furnace process – Basic oxygen furnace process, also known as Linz-Danowitz converter process, or the oxygen converter process, is a method of primary steelmaking in which carbon-rich hot metal (molten pig iron) is made into steel. Blowing oxygen through hot metal iron lowers the carbon content of the alloy and changes it into low-carbon steel.

Basic refractories – Basic refractories are those which are attacked by acid refractories, acid slags, and acid fluxes at high temperature. The major constituent is lime, magnesia, or both. These refractories have resistance to corrosive reactions with chemically basic slags, dusts and fumes at elevated temperatures. Since they do not react with alkaline slags, these refractories are of considerable importance for furnace linings where the environment is alkaline such as steelmaking operations. The most important basic refractories are magnesite refractories, dolomite refractories, and magnesia-chrome refractories.

Basic rocks – These are igneous rocks which are relatively low in silica and composed mostly of dark-coloured minerals.

Basic standards – In the SI (The International System of Units) system, there are seven basic measurement units (Tab 1) from which all other units are derived. All of the units except one are defined in terms of their unitary value. The one exception is the unit of mass. It is defined as 1000 grams (g) or 1 kilogram (kg). It is also unique in that it is the only unit currently based on an artifact. All the standards of mass are based on one particular platinum / iridium cylinder kept at the BIPM (The International Bureau of Weights and Measures, in French: Bureau international des poids et mesures). If that International Prototype Kilogram is to change, then all other mass standards throughout the world becomes wrong.

The meter is the length of the path traveled by light in vacuum during a time interval of 1/299,792,458 of a second. The kilogram is the unit of mass which is equal to the mass of the international prototype of the kilogram. The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom. The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible cross section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 0.0000002 newtons per meter of length. The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water. The unit kelvin and its symbol K is also used to express an interval or a difference in temperature. In addition to the thermodynamic temperature (symbol T), expressed in kelvin, use is also made of Celsius temperature (symbol t) defined by the equation t = T – To where To = 273.15 K by definition. To express Celsius temperature, the unit ‘degree Celsius’ which is equal to the unit ‘kelvin’ is used; in this case ‘degree Celsius’ is a special name used in place of ‘kelvin’. An interval or difference of Celsius temperature can be, however, expressed in kelvins as well as degrees Celsius. The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12. When the mole is used, the elementary entities are to be specified and can be atoms, molecules, ions, electrons, other particles, or specified groups of such particles. In the definition of the mole, it is understood that unbound atoms of carbon-12, at rest, and in their ground state, are referred to. The candela is the luminous intensity, in a given direction, of a source which emits monochromatic radiation of frequency 540 x (10 to the power 12) hertz and which has a radiant intensity in that direction of (1/683) watt per steradian.

Basic static load rating – In bearing, it is a load which, if exceeded on a non-rotating rolling-element bearing, produces a total permanent deformation of rolling element and race at the most heavily stressed contact point of 0.0001 times the ball or roller diameter or greater.

Basic steel – It is the steel made in a furnace with a basic bottom and lining and under a slag containing an excess of a basic substance such as magnesia or lime.

Basket-weave – It consists of alpha platelets with or without inter-leaved beta platelets which occur in colonies in a Widmanstatten structure.

BAT – It is the ‘best available technology’.

Bat – In refractories it means to reject or discard a brick or shape.

Batch – It is a quantity of materials formed during the same process or in one continuous process and having identical characteristics throughout.

Batch annealing – Batch annealing process is the process of annealing cold rolled coil. During batch annealing, very large mass of steel heats and cools very slowly. Batch annealing process needs several days for completion. Annealed grain sizes are coarse, and the slow cooling rates ensure that all carbon dissolved during annealing precipitates upon cooling. Hence, excellent ductility results, although some non-uniformity develops since the inside and outside parts of a coil experience different thermal histories. In this process, the annealing of the cold rolled sheet is carried out in coil form. Normally, 3 to 4 cylindrical steel coils (typically having weight of 10 tons to 30 tons each) are stacked on the base unit of the process for annealing under a protective gas (hydrogen) atmosphere. The process is preferred where large ferrite grains are needed as in the case of electrical steels. The design of a batch annealing unit depends on the steel to be annealed. Basic equipment which are needed for the batch annealing process are (i) a base unit provided with a recirculation fan, (ii) circular convector plates for coil separation, (iii) a protective gas tight cylindrical cover, (iv) a heating hood or heating furnace (also known as bell furnace because of its shape) with burners arranged tangentially, and (v) a cooling hood. The convector plates between the coils are used to improve the heat flow.

Batch furnaces – These are the furnaces which are used to heat treat a single load at a time. Batch type furnaces and kilns, also termed as ‘in-and-out furnaces’ or ‘periodic kilns’ have one temperature set point, but via three zones of control in order to maintain uniform temperature throughout, because of a need for more heat at a door or the ends. They can be loaded manually or by a manipulator or a robot. Loads are placed in the furnace and the furnace and it loads are brought up to temperature together, and depending on the process. Batch-type furnaces are necessary for large parts such as heavy forgings and are preferred for complex alloy grades requiring long cycles.

Batch grinding mills – These mills receive a discrete quantity of charge material which is ground and then discharged. The process is then repeated.

Batch oven – It is an oven which is used to bake a number of cores at one time.

Batch production – It means a system of production wherein products are produced in batches or in group or in lots. It combines the qualities of both job and mass production since production, under this system is done either in anticipation of demand or on the basis of the specific order of the customer.

Batch sintering – It is pre-sintering or sintering in such a manner that compacts are sintered and removed from the furnace before additional unsintered compacts are placed in the furnace.

Bath – It is the molten metal on the hearth of a furnace, in a crucible, or in a ladle.

Batt – It is felted fabrics. It is also structures built by the interlocking action of compressing fibres, without spinning, weaving, or knitting. It is also a fired flat slab of refractory material normally of thin section, used in the firing of ceramic products.

Batter – It is the incline of a wall. It also designates the angle made by the wall surface with the vertical. It is also known as slope of the face of the wall, normally causing a decrease in thickness as the wall ascends. It is the angle at which a face of the wall slopes from the vertical.

Battery – A battery is a device that converts chemical energy contained within its active materials directly into electric energy by means of an electrochemical oxidation-reduction (redox) reaction. This type of reaction involves the transfer of electrons from one material to another through an electric circuit. Battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons. When a battery is connected to an external electric load, those negatively charged electrons flow through the circuit and reach to the positive terminal, hence cause a redox reaction by attracting positively charged ions, cations. Thus, converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term ‘battery’ specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell. In coke making, a battery is a group of ovens in which thermal distillation (coking process) takes place. A battery consists of 20 to 100 adjacent ovens with common side walls made of high-quality silica and other types of refractory bricks.

Bauschinger effect – It is the phenomenon by which plastic deformation increases yield strength in the direction of plastic flow and decreases it in other directions.

Bauxite – It is a rock made up of hydrous aluminum oxides. It is the most common aluminum ore. It is a whitish to reddish mineral composed largely of hydrates of alumina having a composition of Al2O3·2H2O. It is the most important ore (source) of aluminum, alumina abrasives, and alumina base refractories.

Bay – It is the enclosed area between two rows of building columns where equipments are installed. Bay has specified space for storage and passage for the movement of people and equipments. Adequate handling facilities are provided in the bay.

Bayer process – It is a process for extracting alumina from bauxite ore before the electrolytic reduction. The bauxite is digested in a solution of sodium hydroxide, which converts the alumina to soluble aluminate. After the ‘red mud’ residue has been filtered out, aluminum hydroxide is precipitated, filtered out, and calcined to alumina.

B-basis – It is the mechanical property value above which at least 90 % of the population of values is expected to fall, with a confidence of 95 %.

Beach marks – These are macroscopic progression marks on a fatigue fracture or stress-corrosion cracking surface which indicate successive positions of the advancing crack front. The classic appearance is of irregular elliptical or semielliptical rings, radiating outward from one or more origins. Beach marks (also known as clamshell marks or arrest marks) are typically found on service fractures where the part is loaded randomly, intermittently, or with periodic variations in mean stress or alternating stress.

Beacon indicator – It is a highly visible device to show open / closed valve status. It normally incorporates limit switches.

Bead – It is half-round cavity in a mould, or half-round projection or moulding on a casting. It is also a single deposit of weld metal produced by fusion.

Beaded flange – It is a flange reinforced by a low ridge, used mostly around a hole.

Beading – It is raising a ridge or projection on sheet metal.

Beaded tube end – It is the rounded exposed end of a rolled tube when the tube metal is formed over against the sheet in which the tube is rolled.

Bead weld – A weld bead is a rib or fillet formed when two pieces of metal are welded together. It results from the additional filler metal added to ensure good fusion and strength. On a butt joint, the bead is to be raised above the surface. In a fillet joint, the bead to be flat at 45-degree or slightly convex.

Beaker – It is a cylindrical vessel or container with a flat bottom, most commonly a type of glassware, widely used in laboratories for a variety of purposes, such as preparing, holding, containing, collecting, or volumetrically measuring chemicals, samples, or solutions, or as a chamber in which a chemical reaction occurs. Beakers are distinguished from flasks by having straight rather than sloping sides. Majority of the beakers also have a small spout in the rim to aid pouring.

Beams – Beams are either steel joists or parallel flange beams. These products have the characteristics namely (i) the web height is equal to or higher than 80 mm, (ii) the surfaces of the webs are continued by fillets to the inside faces of the flange, (iii) the flanges are normally symmetrical and of equal widths, and (iv) the outside faces of the flanges are parallel. Beams have either ‘H’ section or ‘I’ section. In case of steel joists, the flanges are of decreasing thickness from the web to the edge. Steel joists are also called sloping flanged beams or tapered flanged beams. In case of parallel flange beams the inner surface of the beams are also parallel and the flanges are of uniform thickness. These beams are also known as universal beams. Beams are normally produced as (i) normal section, (ii) thin section, and (iii) thick section.

Beam blank – It is a section whose cross-sectional shape is as close as possible to the shape of the final product. It is also called near-net-shape or dog-bone section. Beam blanks are used to feed medium and heavy section mills.

Beam mill – This rolling mill is used for the production of heavy beam and large channel sections from the blooms.

Beam work – Beams or head frames are used to support steelwork on wire or hooks to allow it to be handled through the galvanizing process.

Bearing – The bearing of a wire drawing die is the final control of the diameter of the drawn wire to guarantee its roundness, straightness, and surface finish.

Bearing area – It is the product of the pin (or hole) diameter and sample thickness in a bearing test. In case of bearings, it is the projected bearing or load-carrying area when viewed in the direction of the load. It is sometimes used as a synonym for real area of contact though this usage is not desired. It is also the sum of the horizontal intercepts of a surface profile at a given level.

Bearing bronzes – These are the bronzes used for bearing applications. Two common types of bearing bronzes are copper-base alloys containing 5 % to 20 % tin and a small quantity of phosphorus (phosphor bronzes) and copper-base alloys containing up to 10 % tin and up to 30 % lead (leaded bronzes).

Bearing capacity – It is the capacity of soil to support the loads applied to the ground. The bearing capacity of soil is the maximum average contact pressure between the foundation and the soil which is not to produce shear failure in the soil. Ultimate bearing capacity is the theoretical maximum pressure which can be supported without failure. Allowable bearing capacity is the ultimate bearing capacity divided by a factor of safety. Sometimes, on soft soil sites, large settlements can occur under loaded foundations without actual shear failure occurring; in such cases, the allowable bearing capacity is based on the maximum allowable settlement. There are three modes of failure that limit bearing capacity: general shear failure, local shear failure, and punching shear failure.

Bearing characteristic number – It is a dimensionless number which is used to evaluate the operating conditions of plain bearings.

Bearing fraction – It is the ratio of the bearing area to a reference length.

Bearing load – A bearing load is defined as the force which is transferred from one bearing ring, through some or all the rolling elements, to the other bearing ring. Application loads normally transfer to the shaft and then to the bearing’s inner ring, then, to the outer ring.

Bearing piles – These are ‘I’ or ‘H’ sections in which the thickness of web and flanges are identical.

Bearing pressure – It is a particular case of contact mechanics frequently occurring in cases where a convex surface (male cylinder or sphere) contacts a concave surface (female cylinder or sphere, bore or hemispherical cup). Excessive contact pressure can lead to a typical bearing failure such as a plastic deformation similar to peening. This problem is also referred to as bearing resistance.

Bearings – Bearings consist of rolling elements (balls, cylinders or barrel shapes) and rings. The rings form the raceways. Bearings are highly engineered, precision-made machine elements which enable relative movement between machine components with minimum friction. Generally speaking, bearings are devices which are used to enable rotational or linear movement, while reducing friction and handling stress. Bearings are considered to be the most critical components of machinery. They constrain relative motion and reduce friction between moving parts to only the desired motion. The design of the bearings can provide for free linear movement of the moving part or for free rotational around a fixed axis, or, it can prevent a motion by controlling the vectors of normal forces which bear on the moving parts. They carry high loads with ease and efficiency and are able to offer high precision, reliability and durability. There are several types of bearings, each used for different purposes. These include ball bearings, roller bearings, ball thrust bearings, roller thrust bearings, and tapered roller thrust bearings.

Bearing steels – Bearing steels are those steels which support a bearing is to sustain severe static and cyclic loads while serving reliably in difficult environments. Steels with carbon concentrations in the range 0.8 % to 1.1 % and the total substitutional solute content of less than 3 %, originally designed for machine tools, have historically dominated the type of steel for bearings. These can be made martensitic by quenching in oil or salt, from a temperature where the material is mostly austenite. The martensite is then subjected to a low temperature tempering in order to balance conflicting properties. There are two categories of steels which find application in the majority of bearings. The first category consists of those steels which are hardened throughout their sections into a martensitic or bainitic condition, and other category consists of those steels which have soft cores but tenacious surface layers introduced using processes such as case or induction hardening. Bearing steels can also be divided in a broad sense into classes such as intended for normal service, high-temperature service, or service under corrosive conditions.

Bearing strain – It is the ratio of the deformation of the bearing hole, in the direction of the applied force, to the pin diameter in a bearing test.

Bearing strength – It is the maximum bearing stress which can be sustained. Also, the bearing stress at that point on the stress-strain curve at which the tangent is equal to the bearing stress divided by ‘n’ % of the bearing hole diameter.

Bearing stress – It is the shear load on a mechanical joint (such as a pinned or riveted joint) divided by the effective bearing area. The effective bearing area of a riveted joint, for example, is the sum of the diameters of all rivets multiplied by the thickness of the loaded member. It is the force per unit of bearing area.

Bearing surface – It is the supporting surface of a fastener with respect to the part it fastens. It is the area of contact between two objects. It is normally used in reference to bolted joints and bearings, but can be applied to a wide variety of engineering applications. On a screw the bearing area loosely refers to the underside of the head. Strictly speaking, the bearing area refers to the area of the screw head which directly bears on the part being fastened. For a cylindrical bearing it is the projected area perpendicular to the applied force. On a spring, the bearing area refers to the quantity of area on the top or bottom surface of the spring in contact with the constraining part. The ways of machine tools, such as dovetail slides, box ways, prismatic ways, and other types of machine slides are also bearing surfaces.

Bearing test – It is a method of determining the response to stress (load) of sheet products which are subjected to riveting, bolting, or a similar fastening procedure. The purpose of the test is to determine the bearing strength of the material and to measure the bearing stress against the deformation of the hole created by a pin or rod of circular cross section that pierces the sheet perpendicular to the surface.

Bearing yield strength – It is the bearing stress at which a material displays a specified limiting deviation from the proportionality of bearing stress to bearing strain in a bearing test.

Becquerel (Bq) – It is the unit of radioactive decay equal to 1 disintegration per second. 37 billion (3.7 x 10 to the power 10) becquerels = 1 curie (Ci).

Bed – It is the stationary portion of a press structure that usually rests on the floor or foundation, forming the support for the remaining parts of the press and the pressing load. The bolster and sometimes the lower die is mounted on the top surface of the bed. For machine tools, the it is portion of the main frame which supports the tool, the work, or both. It is also the stationary part of the shear frame which supports the material being sheared and the fixed blade.

Bedding – It is sinking a pattern down into the sand to the desired position and ramming the sand around it.

Bedding a core – It is placing an irregularly shaped core on a bed of sand for drying.

Bed disturbers – Indirect rotary kilns create heat transfer by conduction through the shell of the rotary kiln, rather than by means of contact with a process gas. Since all of this heat transfer is occurring through the shell, it is essential that the bed rolls rather than slides in order to expose fresh material, allowing for even heat distribution throughout the bed of material. This assures that the transfer of heat is as efficient as possible. For this reason, when processing material in an indirect fired kiln, it is frequently desirable to use a bed disturber. Bed disturbers are also normally used in a direct fired kiln for the same reason where the bed disturber helps to prevent the bed from sliding, as well as promotes more uniform heating. A bed disturber, frequently custom designed to create maximum material specific efficiency, is essentially anything affixed to the inside of the rotary kiln which helps to mix the bed of material.

Beehive oven – It is a simple domed shape firebrick chamber built with an arched roof so that the shape inside is that of an old-fashioned beehive. Its dimensions are typically 4 metre wide and 2.5 metre high. Beehive ovens are normally built in rows, one oven beside another with common walls between neighboring ovens. Such a row of ovens is termed a battery. A battery normally consists of several ovens, sometimes hundreds, in a row.

Beer’s law – It is a relationship in which the optical absorbance of a homogeneous sample containing an absorbing substance is directly proportional to the concentration of the absorbing substance.

Before-after study – It is a study wherein data are collected prior to and following an event, treatment, or action. The event, treatment, or action applied between the two periods is thought to affect the data under investigation. The purpose of this type study is to show a relationship between the data and the event, treatment, or action. In experimental study all other factors are either randomized or controlled.

Beginning of observation – In survival analysis, it is the moment in time when subjects begin to be followed by the person carrying the studies.

Beilby layer – It is a layer of metal disturbed by mechanical working, wear, or mechanical polishing presumed to be without regular crystalline structure (amorphous). It has been originally applied to grain boundaries.

Bell – In blast furnaces with two bell charging system, two numbers of bells (small and big) are used to control the entry of charge materials in the blast furnace as well as to prevent escape of blast furnace gas in the environment. These bells are of conical shape. It is also a jar like enclosure for containing vacuum or a controlled atmosphere in sintering equipment used for tungsten, tantalum, and other refractory metal bars.

Belleville spring, Belleville washer – It is a conical shell which can be loaded along its axis either statically or dynamically. A Belleville washer is a type of spring shaped like a washer. It is the shape, a cone frustum, which gives the washer its characteristic spring. It is used in some valves to push the seats against the closure element.

Bell furnace – It is a cylindrical furnace in top hood design, that is the furnace kept on the fixed bases in the inverted position. An overhead crane of suitable capacity from one base to another base carries the furnace itself.

Bell jar – It is a container open at one end (normally the bottom) which is used as a vacuum chamber or test vessel.

Bell jar test – It is a test used for detecting leakage from an object completely or partially filled with a tracer gas and placed in a vacuum chamber or bell jar.

Bell type furnace – It is a furnace for the sintering of large batches of small pieces under a controlled atmosphere.

Bell less top equipment – It is the furnace charging equipment which does not use the two bells but uses a rotating chute for furnace charging.

Bell overhang – It is the vertical distance between the bottom of the large bell closed and the inner bell seat.

Bellows – it is the flexible element of a pipe expansion joint consisting of one or more convolutions and the end tangents, if any. It is also a device constructed to furnish a strong blast of air. Bellows are widely used in industrial and mechanical applications such as rod boots, machinery way covers, lift covers and rail covers to protect rods, bearings and seals from dirt. Bellows are used in mechanical aneroids by acting as a precision indicator of pressure levels based on their lateral movement. Bellows tubing, a type of lightweight, flexible, extensible tubing can be used for delivery of gas or air at near-ambient pressure. Metal bellows are elastic vessels that can be compressed when pressure is applied to the outside of the vessel, or extended under vacuum. When the pressure or vacuum is released, the bellows return to its original shape, provided the material has not been stressed past its yield strength. They are used both for their ability to deform under pressure and to provide a hermetic seal that allows movement.

Bellows, blast furnace – These are part of tuyere stock. It accommodates relative movement of blow pipe with respect to bustle pipe. Bellows can normally adjust movements up to 3.5 degrees.

Bellow seal valve – A bellow seal valve is a control valve which does not have a conventional gland packing and instead of that these valves have a bellow cartridge and this is welded to the valve’s bonnet and stem. The bellow can be compared to a coiled spring since it can be flexed in compression or in extension. The bellow seal valve is similar to a globe valve and their only difference is that in a globe valve people can see a gland packing along the stem but in a bellow seal valve, bellows are used to prevent the leakage instead of the packing. These valves are totally leakproof and can handle corrosive liquids.

Bellows seal – It is a type of mechanical seal which utilizes a bellows for providing secondary sealing.

Bell radius – It is a section of a wiredrawing die which provides a smooth contour into the entrance and the approach angle, allowing lubricant to reach the working surface of the die.

Bell reducer – It is a pipe fitting which is shaped like a bell. It has one opening of a smaller diameter used to reduce the size of the pipe in the line, and the opposite opening of larger diameter.

Belly – It is the cylindrical portion of the blast furnace below the stack. It connects the upper bosh diameter with the largest diameter of the lower stack. It is also a loose centre buckle extending to near the edges of a sheet.

Belt conveyor – A belt conveyor is a material handling system which uses continuous belts to convey products or materials. A belt conveyor installation consists of a drive system, a take-up system, additional components and auxiliary items, and the principal item ‘the conveyor belt’. The conveyor belt is an endless flat and flexible belt of sufficient strength, which is laid over two metallic flat pulleys at two ends, and which is driven in one direction by driving one of the two end pulleys. Material is placed on this moving belt for transportation. The belt is extended in an endless loop between two end-pulleys.  Normally, one or both ends have a roll underneath. The conveyor belting is supported by either metal slider pans for light loads where no friction is to be applied to the belt to cause drag or on rollers. Power is provided by motors which use either variable or constant speed reduction gears. The endless belt is kept tight by a belt tensioning arrangement. Belt conveyors are normally used to transport and distribute materials. They are also suitable for performing numerous processing functions in addition to their normal purpose of providing a continuous flow of material between two operations.

Belt conveyor idlers – Belt conveyor idlers are the rollers which are used at certain spacing for supporting the active as well as return side of the conveyor belt. Important requirements for idlers are proper support and protection for the belt and proper support for the load being conveyed. Belt conveyor idlers for bulk materials are designed to incorporate rolls with different diameters. The rolls are fitted with antifriction bearings and seals, and are mounted on shafts. Frictional resistance of the idler roll influences belt tension and, hence, the power requirement.

Belt drive – It consists of an endless belt which is wrapped tightly over two pulleys called the driving and the driven pulley mounted on their respective shafts. The motion from the driving pulley is transmitted to the driven pulley by the frictional resistance between belt and the surface of the pulley.

Belt feeders – These are used to provide a controlled volumetric flow of bulk materials from the storage units. They normally consist of a flat belt supported by closely spaced idlers and driven by end pulleys. They are suited for handling of granular materials of comparatively lesser lump size. The limitation of lump size depends upon toughness, hardness, abrasiveness and roughness of the lumps.

Belt friction – It is a term describing the friction forces between a belt and a surface.

Belt furnace – It is a continuous-type furnace which uses a mesh-type or cast-link belt to carry parts through the furnace.

Belt grinding – It is the grinding with an abrasive belt.

Belt training idlers – These idlers help control belt alignment in difficult situations. They pivot around an axis vertically perpendicular to the centre line of the belt, and when the belt becomes off-centre, the idlers swing about so that the axes of the rolls themselves become canted in a corrective direction. This swinging action around the centre pivot is accomplished in different ways normally associated with the pressure of the off-centre belt against a fixed arm attached to the idler frame.

Belleville-spring – It is a disc shaped spring normally used to apply tension to a bolt. It is used in the initiation mechanism of pressure activated landmines. It is also known as Belleville washer.

Bench – In open-pit mining it is yeh horizontal steps /increments mined as the open pit progresses deeper.

Benchmarking – It is a systematic way to identify superior products, services, processes, and practices which can be adopted by the organization for improving the performance. It provides the organization practicing it, a big opportunity for gaining a strategic, operational, and financial advantage. Benchmarks are adopted as targets for optimal organizational performance, and can include standards or management processes.

Bench moulding – It consists of casting sand moulds by hand tamping loose or production patterns at a bench without the assistance of air or hydraulic action.

Bend or twist (defect) – It is the distortion similar to warpage normally caused during forging or trimming operations. When the distortion is along the length of the part, it is termed bend. When across the width, it is termed twist. When bend or twist exceeds tolerance, it is considered a defect. Corrective

Bend allowance – It is the length of the arc of the neutral axis between the tangent points of a bend.

Bend angle – It is the angle through which a bending operation is performed, that is, the supplementary angle to that formed by the two bend tangent lines or planes.

Bending – It is the straining of material, normally flat sheet or strip metal, by moving it around a straight axis lying in the neutral plane. Metal flow takes place within the plastic range of the metal, so that the bent part retains a permanent set after removal of the applied stress. The cross section of the bend inward from the neutral plane is in compression; the rest of the bend is in tension.

Bending brake – It is a form of open-frame single-action press that is comparatively wide between the housings, with a bed designed for holding long, narrow forming edges or dies. It is used for bending and forming strip, plate, and sheet (into boxes, panels, roof decks, and so on). It is also known as press brake.

Bending dies – These are the dies used in presses for bending sheet metal or wire parts into different shapes. The work is done by the punch pushing the stock into cavities or depressions of similar shape in the die or by auxiliary attachments operated by the descending punch.

Bending fatigue – It is caused by repeated bending stresses that exceed the local fatigue strength in the tensile root fillet of a gear tooth. A fatigue crack initiates at the surface of the root fillet and propagates into the gear tooth normal to the root fillet surface.

Bending moment – It is the algebraic sum of the couples or the moments of the external forces, or both, to the left or right of any section on a member subjected to bending by couples or transverse forces, or both.

Bending rolls – Different types of machinery equipped with two or more rolls to form curved sheet and sections.

Bending stress – It is a stress involving tensile and compressive forces, which are not uniformly distributed. Its maximum value depends on the quantity of flexure which a given application can accommodate. Resistance to bending can be termed stiffness.

Bending-twisting coupling – It is a property of certain classes of laminates which show twisting curvatures when subjected to bending moments.

Bend line – It is the horizontal line at the upper termination of the in-wall batter.

Bend radius – It is the inside radius of a bend section. It is also the radius of a tool around which metal is bent during fabrication.

Bend tangent – It is a tangent point at which a bending arc ceases or changes.

Bend test – It is a test for determining relative ductility of metal, i.e., to be formed (normally sheet, strip, plate, rod, or wire) and for determining soundness and toughness of metal (after welding, for example). The sample is normally bent over a specified diameter through a specified angle for a specified number of cycles.

Beneficiation – It is the improvement of concentration or other preparation of ore for smelting.

Beneficiation process – It is the process of the treatment of ore to improve physical or chemical properties especially in preparation for the smelting of ore. It improves (benefits) the economic value of the ore by removing the gangue minerals, which results in a higher-grade product (ore concentrate) and a waste stream (tailings). There are many different types of beneficiations, with each step furthering the concentration of the original ore. Beneficiation includes crushing, grinding, gravity concentration and flotation concentration. Beneficiation is followed by processing activities such as smelting and refining. The beneficiation process begins with crushing and grinding, which is followed by flotation for further beneficiation.

Benefit-cost analysis – It is a form of economic analysis in which the economic benefits and costs of a project are determined with due allowance for the time value of money.

Bentonite – Bentonite is a clay consisting mainly of smectite minerals, normally formed by the decomposition of volcanic ash or tuff, or sometimes from other igneous or sedimentary rocks. Bentonite is a very plastic clay. It is an absorbent swelling clay consisting mostly of montmorillonite which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably higher swelling capacity than Ca-montmorillonite.

Benzene – It is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal ring with one hydrogen atom attached to each. Since it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon. Benzene is a colourless or light-yellow liquid at room temperature. It has a sweet odour and is highly flammable. Benzene evaporates into the air very quickly. Its vapour is heavier than air and can sink into low-lying areas. Benzene dissolves only slightly in water and floats on top of water.

Bernoulli equation – The Bernoulli equation is an equation for flow based on the law of conservation of energy, which states that the total energy of a fluid or gas at any one point in a flow is equal to the total energy at all other points in the flow.

Bernoulli’s theorem – Bernoulli’s theorem states that, at any point in a full system, the sum of the potential energy, kinetic energy, pressure energy, and frictional energy of a flowing liquid is equal to a constant.

Beryllium – It is a chemical element. It has symbol ‘Be’ and atomic number 4. It is a steel-gray, hard, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form minerals. It is relatively soft and has a low density. It is used in alloys with copper or nickel to make gyroscopes, springs, electrical contacts, spot-welding electrodes and non-sparking tools.

Beryllium copper – It consists of copper alloys with 1.5% to 2 % beryllium additions which have the highest strengths of all copper alloys by both heat treatment (solution treatment and age hardening) and cold working.

Beryllium window – It is a very thin (around 7.5 micrometers thick), relatively x-ray transparent window separating the x-ray detector from the vacuum chamber, which serves to protect the detector from damage.

Bessemerization – It is a metallurgical process in which the air is blown to the copper matte which is kept in the Bessemer converter. And this blast of air converts a part of copper sulphide to copper oxide. The molten copper formed is to be 99 % pure copper and it is also called Bessemer copper.

Bessemer matte – The product from smelting the feeds in the Bessemer process is normally a primary smelting matte which needs further processing, typically in Peirce Smith converters, to produce finished grade matte. The finished grade matte is called ‘Bessemer matte’.

Bessemer process – The Bessemer process has been the first inexpensive industrial process for the mass production of steel from hot metal (molten pig iron) before the development of the open-hearth furnace. The key principle is removal of impurities from the iron by oxidation with air being blown through the molten iron. Bessemer converter is an egg-shaped, silica, clay, or dolomite-lined containers with capacities of 5 tons to 30 tons of hot metal. An opening at the narrow upper portion of the Bessemer converter allows hot metal to be introduced and the liquid steel to be poured out. This process is now has become obsolete.

Best efficiency point – The equation for total efficiency is an important aspect of a fan performance curve and it is the best efficiency point, where a fan operates most cost-effectively in terms of both energy efficiency and maintenance considerations.

Best management practices (BMPs) – These are beneficial management practices. These are techniques and procedures which have been proven through research, testing, and use to be the most effective and appropriate for use in an organization. Effectiveness and appropriateness are determined by the performance against the key performance indicators of the organization.

Beta -It is the high-temperature allotrope of titanium with a body-centered cubic crystal structure which occurs above the beta transus.

Beta annealing – It consists of producing a beta phase by heating certain titanium alloys in the temperature range of which this phase forms followed by cooling at an appropriate rate to prevent its decomposition.

Beta brass – It is a brass with very high zinc content. It has a predominantly beta phase micro-structure, is brittle and used only as a brazing filler alloy.

Beta decay – It is a particular type of radioactive decay in which a beta particle is emitted from an atom. Beta decay can occur in two forms: beta minus or beta plus.

Beta distribution – It is a probability distribution used to model the activity times in programme evolution review technique (PERT).

Beta emitter – It is a radionuclide which decays by emission of an electron or positron.

Beta eutectoid stabilizer – It is an alloying element which dissolves preferentially in the beta phase, lowers the alpha-beta to beta transformation temperature, and results in beta decomposition to alpha plus a compound. This eutectoid reaction can be sluggish for some alloys.

Beta fleck – It is alpha-lean region in the alpha-beta micro-structure significantly larger than the primary alpha width. This beta-rich area a bata transus measurably below that of the matrix. Beta flecks have reduced quantities of primary alpha which can show a morphology different from the primary alpha in the surrounding alpha-beta matrix.

Beta isomorphous stabilizer – It is an alloying element which dissolves preferentially in the beta phase, lowers the alpha-beta to beta transformation temperature without a eutectoid reaction, and forms a continuous series of solid solution with beta-titanium.

Beta minus – It is the Beta decay in which an electron is emitted from an atom.

Beta particle – It is an electron emitted by the nucleus of a radionuclide in beta decay.

Beta phase – It is a phase in the micro-structure of brasses which contain more than around 36 % zinc. Beta phase adversely affects the cold formability of brasses and hot working processes, such as hot stamping, are preferred.

Beta plus – It is Beta decay in which a positron is emitted from an atom.

Beta ratio – Beta ratio in an orifice plate is the ratio between the line inner diameter to bore size of the orifice. The flow coefficient is found to be stable between beta ratio is between 0.2 to 0.7 below which the uncertainty in flow measurement increases.

Beta ray – It is a ray of electrons emitted during the spontaneous disintegration of certain atomic nuclei.

Beta structure – It is a Hume-Rothery designation for structurally analogous body-centered cubic phases (similar to brass) or electron compounds which have ratios of three valence electrons to two atoms.

Beta transus – It is the minimum temperature above which equilibrium alpha does not exist. For beta eutectoid additions, the beta transus ordinarily is applied to hypo-eutectoid compositions or those which lie to the left of the eutectoid composition.

Between-subjects variable – it is a variable in repeated-measures ANOVA or linear mixed modelling which does not change over time for a given subject but takes on different values for different subjects.

Bevel – It is an angular edge preparation in a weld member.

Bevel angle – It is the angle formed between the prepared edge of a member and a plane perpendicular to the surface of the member.

Bevel brick – It is a brick shape in which one edge, between two adjacent faces, is replaced by a bevel.

Bevel gear operated (BGO) – It is the actuation of a valve by means of a set a gear where the axes of the two shafts intersect and the tooth-bearing faces of the gears are conically shaped. The reduction ratio of this gear determines the torque ratio achieved. It is mainly used on gate valves.

Bevel gears – Bevel gears have teeth cut on an angular or conical surface unlike spur and helical gears with teeth cut from a cylindrical blank. Bevel gears are used when input and output shaft centerlines intersect. Teeth are normally cut at an angle so that the shaft axes intersect at 90-degree, but any other angle can be used. There are two basic classes of bevel gears (i) straight tooth, and (ii) spirals.

Bevel groove weld – It is a type of groove weld.

Beyond design basis accident – It is an accident which is more serious than the one against which the plant has been designed.

Bias – It is a constant error which takes place in the instrument when the pointer is not starting from zero scale. It is also sometimes known as zero drift. Bias or zero drift describes the effect where the zero reading of an instrument is modified by a change in ambient conditions. This causes a constant error which exists over the full range of measurement of the instrument. Zero drift is normally removable by calibration. It is a systematic error inherent in a method (such as temperature effects and extraction inefficiencies) or caused by some artifact or idiosyncrasy of the measurement system (such as blanks, contamination, mechanical losses, and calibration errors). Bias can be both positive and negative, and several types can exist concurrently, so that the net bias is all that can be evaluated except under certain conditions. In statistical analysis, in problems of estimation of population parameters, an estimator is assumed biased if its expected value does not equal the parameter it is intended to estimate. In sampling, a bias is a systematic error introduced by selecting items non-randomly from a population which is assumed to be random. A survey question can be biased if it is poorly phrased.

Biased estimator – It is a sample statistic which is an inaccurate estimator of the corresponding population parameter, in particular, the mean of its sampling distribution is not equal to the population parameter.

Bias fabric – It is the warp and fill fibres at an angle to the length of the fabric.

Bi-axiality – In a biaxial stress state, it is the ratio of the smaller to the larger principal stress.

Bi-axial load – It is a loading condition in which a laminate is stressed in two different directions in its plane. It is a loading condition of a pressure vessel under internal pressure and with unrestrained ends.

Bi-axial stress – It is a state of stress in which only one of the principal stresses is zero, the other two normally being in tension.

Bi-axial winding – In filament winding, it is a type of winding in which the helical band is laid in sequence, side by side, with crossover of the fibres eliminated.

Bi-directional laminate – It is a reinforced plastic laminate with the fibres oriented in two directions in its plane. It is also called a cross laminate.

Bi-directional seal – It is a seal which is designated to seal equally well when the pressure is applied from either direction.

Bi-directional valve – It is a valve which is designed for blocking the fluid and can be installed with either of the flange ends in the upstream or downstream direction.

Bifurcation – It is the separation of materials into two parts.

Big-end bearing – It is a bearing at the larger (crankshaft) end of a connecting rod in an engine. It is also known as bottom-end bearing, crankpin bearing, and large-end bearing.

Billet – It is a semi-finished section which is hot rolled from a metal ingot or bloom, with a rectangular cross section normally ranging from 105 square centimeters to 230 square centimeters, the width being less than twice the thickness. Where the cross section exceeds 230 square centimeters, the term bloom is used, but not universally used. Sizes smaller than 105 square centimeters are normally termed bars. It is also a solid semifinished round or square product which has been hot worked by forging, rolling, or extrusion.

Billet mill – It is a primary rolling mill which roll billets from the blooms.

Bimetal – It a casting, normally centrifugal, made of two different metals, fused together.

Bimetal bearing – It is a bearing consisting of two layers. It is to be noted that the bimetal bearings are normally made with a layer of bearing alloy on a bronze or steel backing.

Bimetallic strip or bimetal strip is a strip that consists of two strips of different metals which expand at different rates as they are heated. They are used to convert a temperature change into mechanical displacement. The different expansions force the flat strip to bend one way if heated, and in the opposite direction if cooled below its initial temperature. The metal with the higher coefficient of thermal expansion is on the outer side of the curve when the strip is heated and on the inner side when cooled.

Bi-metallic thermometers – Bonding two dissimilar metals with different coefficients of expansion produces a bi-metallic element. These are used in bi-metallic thermometers, temperature switches, and thermostats having a range of -70 deg C to 540 deg C. When manufactured as a helix or coil, its movement with a change in temperature can move a pointer over a dial scale to indicate temperature.

Binary alloy – It is an alloy which contains only two component elements.

Binary aluminum copper alloys – These are aluminum alloys that consist largely of aluminum and traces of copper as the main alloying elements. Important grades also contain additives of magnesium, iron, nickel and silicon, often manganese is also included to increase strength. The main area of application is aircraft construction. The alloys have medium to high strength and can be age hardened. They are both wrought alloy and as cast alloy. Their susceptibility to corrosion and their poor weldability is disadvantageous.

Binary diagram – Binary phase diagram is an isomorphous system. The diagram consists of two single-phase fields separated by a two-phase field. The boundary between the liquid field and the two-phase variables. It is used to determine whether or not two variables are related. that between the two-phase field and the solid field is the solidus.

Binary eutectic – It means a phase diagram that consists of two elements which are not completely soluble in the solid state.

Binary isomorphous – It means a phase diagram that consists of two elements which are completely soluble in both the liquid and solid states.

Binary system – It is the complete series of compositions produced by mixing a pair of components in all proportions.

Binder – In powder metallurgy, it is a cementing medium which is either a material added to the powder to increase the green strength of the compact, which is expelled during sintering, or a material (normally of relatively low melting point) added to a powder mixture for the specific purpose of cementing together powder particles which alone do not sinter into a strong body. It is a substance for holding compacted metal powder together while it is being sintered. In foundry, it is a material, other than water, added to foundry sand to bind the particles together, sometimes with the use of heat. A binder for a foundry mould or core comprises an alkali metal salt of a polyvalent organic acid or a polymerized monovalent organic acid, for example sodium polyacrylate, and an alkaline earth hydroxide such as calcium hydroxide, together with a suitable solvent. In refractories, binder is a substance added to a granular material to give it workability and green or dry strength. In cast refractories, binders are the glue which holds the formed cast refractory together. Organic binders, which get burned out during firing, can be used. Inorganic binders, however, remain within the material and play an integral part in the formed shape.

Binder metal – It is a metal used as a binder. An example is cobalt which is used in cemented carbides.

Binder phase – It is the soft metallic phase which cements the carbide particles in cemented carbides. More generally, it is a phase in a heterogeneous sintered material which gives solid coherence to the other phase(s) present.

Bingham solid – It is an idealized form of solid which begins to flow appreciably only when a certain stress, called the yield stress or yield point, has been exceeded. The solid subsequently flows at a rate proportional to the difference between the applied stress and this yield stress. It is to be noted that several greases can be regarded as Bingham solids.

Binodal curve – In a two-dimensional phase diagram, it is a continuous line consisting of both of the pair of conjugate boundaries of a two-phase equilibrium which join without inflection at a critical point.

Binomial distribution – The binomial distribution is used to model data from categorical variables, when there are just two categories, or levels.

Binomial test – It is an exact test of the statistical significances of derivations from a theoretically expected distribution of observations into two categories.

Bins – Bins are large containers of cylindrical or rectangular shape made from steel sheet / plate supported on legs. Filling of bins is from the open or covered top and discharge is from the bottom opening. Inside agitators or outside vibrators are frequently used for facilitating the flow of materials from the discharge opening. Conveyors, bucket elevators, and pneumatic conveyors are normally used for delivery of materials into the bins. Discharge of materials from the bins at the desired rate is carried out by using different types of feeders.

Biocides – Biocides are used for the control of bacterial and fungus growth.

Bio-degradable – It is the degradation of material from naturally occurring micro-organisms, such as bacteria, fungi or algae over a period of time.

Bio-fuel – Bio-fuel is fuel derived from organic matter instead of from fossil products.

Bio-leaching – It is a process for recovering metals from low-grade ores by dissolving them in solution, the dissolution being aided by bacterial action.

Biological corrosion – It is the deterioration of metals as a result of the metabolic activity of micro-organisms.

Biological diversity – It is also known as biodiversity. It is the variability among living organisms and the ecological complexes of which they are a part. This includes the diversity found within and between species and ecosystems.

Biological oils – These are basically the vegetable (castor, palm, or rapeseed) oils and animal-based oils. Vegetable based lubricating oils are less stable (rapid oxidation) than the mineral oil-based lubricating oils at high temperature. These lubricating oils contain more natural boundary lubricants than the mineral oils. Biological based lubrication oils are suitable in applications where the risk of contamination is required to be reduced to a minimum. They are normally applied to lubricate kilns, and bakery ovens etc.

Biological oxygen demand (BOD) – It is also known as biochemical oxygen demand. It is an analytical parameter representing the quantity of dissolved oxygen consumed by aerobic bacteria growing on the organic material present in a water sample at a specific temperature over a specific time period. The biological oxygen demand value is normally expressed in milligrams of oxygen consumed per litre of sample during 5 days of incubation at 20 deg C and is frequently used as a surrogate of the degree of organic water pollution. Biological oxygen demand reduction is used as a gauge of the effectiveness of wastewater treatment plants. Biological oxygen demand of wastewater effluents is used to indicate the short-term impact on the oxygen levels of the receiving water.

Biological shield – This is a mass of absorbing material which is placed around a reactor or radioactive source in order to reduce the radiation to a level safe for humans.

Bio-material – It is a material derived from, or produced by, biological organisms like plants, animals, bacteria, fungi and other life forms. It is also called biologically derived material. For example, a polymer which is a macromolecule which is composed of monomers that are assembled biologically. It is like making a chain using several links which can be the same or different.

Biosolids – These are treated solid or semi-solid residues generated during the treatment of domestic sewage in a waste-water treatment facility. Primarily these are an organic product produced by waste-water treatment processes which can be beneficially used.

Bipolar electrode – It is an electrode in an electrolytic cell which is not mechanically connected to the power supply, but is so placed in the electrolyte, between the anode and cathode, that the part nearer the anode becomes cathodic and the part nearer the cathode becomes anodic.

Bipolar field – It is a longitudinal magnetic field which creates two magnetic poles within a piece of material.

Birefringence – It is a double-refraction phenomenon in anisotropic materials in which an unpolarized beam of light is divided into two beams with different directions and relative velocities of propagation. The quantity of energy transmitted along an optical path through a crystal which shows birefringence becomes a function of crystalline orientation.

Birefringent crystal – It is a crystalline substance which is anisotropic with respect to the velocity of light.

Bi-rotational seal – It is a seal which is designed for applications in which a shaft rotation is in either direction.

Bismaleimide (BMI) – It is a type of polyimide which cures by an addition rather than a condensation reaction, hence avoiding problems with volatiles formation, and which is produced by a vinyl-type polymerization of a prepolymer terminated with two maleimide groups. It is intermediate in temperature capability between epoxy and polyimide.

bisphenol ‘A’ – It is a condensation product formed by the reaction of two molecules of phenol with acetone. This polyhydric phenol is the standard intermediate resin which is reacted with epichlorohydrin in the production of epoxy resins.

Bisque – It is a coating of wet process porcelain enamel which has been dried, but not fired.

Bi-state/phase change sensors – These low-cost non-electric sensors are made from heat-sensitive fusible crystalline solids which change decisively from a solid to a liquid with a different colour at a fixed temperature depending on the blend of ingredients. They are available as crayons, lacquers, pellets, or labels over a wide range of temperatures from 38 deg C to 1,650 deg C. They offer a very inexpensive method for surface temperature visual verification within around 0.5 deg C. Monitoring minimum and maximum temperatures during shipment of perishable goods is a common application.

Bit – It is that part of the soldering iron, normally made of copper, which actually transfers heat (and sometimes solder) to the joint.

Bituminous coal – It is an organic sedimentary rock formed by diagenetic and sub metamorphic compression of peat bog material. It is also called as black coal. It is frequently referred to as soft coal. However, this designation is a layman’s term and has little to do with the hardness of the rock. It is defined as a medium‐rank coal with either a gross calorific value on a moist, ash‐free basis of not less than 24 MJ/kg (mega joules per kilogram) and with a Vitrinite mean Random Reflectance less than 2.0 %, or with a gross calorific value on a moist, ash‐free basis of less than 24 MJ/kg provided that the Vitrinite mean random reflectance is equal to, or greater than 0.6 %.

Bivariate data analysis – It is a statistical test which involves two separate variables. It is used to determine whether or not two variables are related.

Bivariate statistics – It is the statistical procedures for testing and assessing the association between two different variables.

Bivariant equilibrium – When both the pressure and temperature in a unary system are freely and arbitrarily selected, the situation corresponds to having two degrees of freedom, and the phase rule says that only one phase can exist in stable equilibrium. This situation is known as bivariant equilibrium.

Black annealing – It is box annealing or pot annealing ferrous alloy sheet, strip, and wire to impart a black colour to the oxidized surface.

Black-body – It is a hypothetical ‘body’ which completely absorbs all incident radiant energy, independent of wave-length and direction, i.e., that neither reflects nor transmits any of the incident radiant energy.

Blacking or Blacking carbon – Carbonaceous materials such as plumbago, graphite or powdered coke normally mixed with a binder and frequently carried in suspension in water or other liquid. It is used as thin facing applied to surfaces of moulds or cores to improved casting finish.

Black liquor – It is the liquid material remaining from pulpwood cooking in the soda or sulphate paper-making process.

Black nickel – It is electrolytic nickel plating with a secondary treatment to turn the surface black. This plating provides corrosion resistance and maintains electrical conductivity while reducing reflectivity on the surface.

Black oxide – It is a black finish on a metal produced by immersing it in hot oxidizing salts or salt solutions.

Black oxide finish – This characteristic black oxide finish is typically applied to drills and other cutting tools by oxidizing in a steam atmosphere at around 540 deg C. The black oxide surface has little or no effect on hardness, but serves as a partial barrier to galling of similar ferrous metals. The surface texture also permits retention of the lubricant.

Black plates – These are non-alloyed, low C steel sheet or strip, which have been single or double cold, reduced. Single reduced black plate is supplied in thicknesses from 0.17 mm to 0.50 mm, and double reduced black plate is supplied in thicknesses from 0.14 mm to 0.30 mm. Black plates are generally used to manufacture tinplate or electrolytic chromium coated steel. The product is to be suitable for varnishing (lacquering) or printing.

Blacksmith welding – It is a non-standard term for forge welding.

Bladder – It is an elastomeric lining for the containment of hydro-proof or hydro-burst pressurization medium in filament-wound structures.

Blank – Blanks are semi-finished products which intended for the manufacture of sections and which have a rough shape of the section. The cross-sectional area of the blanks for sections is normally higher than 25,600 sq mm. A blank is also a section of sheet which has the same outer dimensions as a specified part (such as a car door or hood), but which has not yet been stamped. In forming, it is a piece of sheet metal, produced in cutting dies, which is normally subjected to further press operations. In powder metallurgy, it is a pressed, pre-sintered, or fully sintered compact, normally in the unfinished condition and needing cutting, machining, or some other operation to produce the final shape. In forging, it is a piece of stock from which a forging is made, frequently called a slug. In material characterization, blank is the measured value obtained when a specified component of a sample is not present during the measurement. In such a case, the measured value / signal from the component is believed to be because of the artifacts, and hence is to be deducted from a measured value to give a net value due to the component contained in a sample. The blank measurement is to be made so that the correction process is valid.

Blank carburizing – It consists of simulating the carburizing operation without introducing carbon. This is normally accomplished by using an inert material in place of the carburizing agent, or by applying a suitable protective coating to the ferrous alloy.

Blanket – It is a fibre or fabric plies which have been laid up in a complete assembly and placed on or in the mould all at one time (flexible bag process). It is also, the type of bag in which the edges are sealed against the mould.

Blank holder – It is the part of a drawing or forming die that holds the work-piece against the draw ring for controlling metal flow. It is also the part of a drawing or forming die which restrains the movement of the work-piece for avoiding wrinkling or tearing of the metal.

Blanking – It is the operation of punching, cutting, or shearing a piece out of stock to a pre-determined shape.

Blanking shear test – It is a method used to determine the through-thickness shear strength of sheet material which involves blanking a disk out of flat strip using a simple punch-and-die method. It is also known as punching shear test.

Blank nitriding – It consists of simulating the nitriding operation without introducing nitrogen. This is normally accomplished by using an inert material in place of the nitriding agent or by applying a suitable protective coating to the ferrous alloy.

Blast cleaning or blasting – It is a process for cleaning or finishing metal objects by use of an air blast or centrifugal wheel which throws abrasive particles against the surface of the work pieces. Small, irregular particles of steel or iron are used as the abrasive in grit blasting, and steel or iron balls in shot blasting.

Blast furnace – Blast furnace is essentially a counter-current moving bed vertical shaft metallurgical furnace with solids (iron bearing burden, coke and flux), and later molten liquids, travelling down the shaft. It is used for smelting iron ore to produce liquid iron.

Blast furnace coke – Blast furnace coke is a hard carbon material produced in the process of the ‘destructive distillation’ of various blends of bituminous coal. It is produced by carbonization of coal at high temperatures (1,100 deg C) in an oxygen deficient atmosphere in a coke oven. It is the fraction of coke in the size range of 30 mm to 80 mm.

Blast furnace gas – It is a byproduct gas produced during the production of hot metal in a blast furnace, where iron ore is reduced with coke to produce hot metal. The blast furnace gas which comes out from the top of the blast furnace is normally at a high pressure of 0.15 MPa to o.25 MPa) and at a temperature of around 100 deg C to 150 deg C. The calorific value of the blast furnace gas varies between 2.72 MJ (mega joules) to 3.75 MJ per normal cubic metre and depends on the carbon mono oxide concentration. It is colourless, flammable toxic gas. It has a caloric value of around 1.25 kilograms per cubic metres the standard temperature and pressure (0 deg C temperature and o.1 MPa pressure).

Blast furnace refractories – These are the refractories used for the lining of the blast furnace. There are several varieties of refractory materials for blast furnace lining, and blast furnace lining is also a continuously improving technology.

Blast furnace slag – It is the non-metallic product consisting essentially of silicates and alumino-silicates of calcium and other bases that is developed in a molten condition simultaneously with iron in a blast furnace. There are two main types of BF slag categorized by how it is cooled. These are air-cooled slag and granulated slag. It is mildly alkaline and shows a pH in solution in the range of 8 to 10. The chemical composition of the blast furnace slag normally has four major oxides namely CaO, MgO, SiO2, and Al2O3. These four oxides normally make up of around 95 % of the total. Minor elements include sulphur, iron, manganese, alkalis, and trace amounts of several others.

Blast furnace tap hole mass – It is a prepared ready to use refractory product, made of a bond of aggregates, additives, and plasticizers. It is used to close the tap hole of a blast furnace after tapping so that no material can leak out, and to keep it plugged until the tap hole is opened for next tapping. It is applied to ensure periodical and stable tapping from the blast furnace and also to protect the inner surface of tap hole bricks. Its functions are (i) to enable smooth operation of the tap hole, (ii) to maintain constant tap hole length, (iii) to control the liquid flow out of the blast furnace, and (iv) to ensure separation of hot metal and slag.

Blast furnace valves – These are the valves needed by the blast furnace. During ironmaking in the BF, a number of gases, utilities, and dust are to be handled. These include (i) combustion gas, combustion air, and waste flue gas in hot blast stoves, (ii) cold air blast, oxygen, and hot air blast, (iii) blast furnace top gas and its cleaning, (iv) solid materials and (v) cooling water. The handling and the control of these gases and fluids necessitate use of different types of valves which include gate valves, goggle valves, butterfly valves, chimney valves, crude gas bleeder valves, and equalizing / relief valves etc.

Blast-hole – It is a drill hole in a mine which is filled with explosives in order to blast loose a quantity of rock.

Blast pressure – It is the pressure of the hot blast air Injected in blast furnace through the tuyeres.

Bleach – It is the generic name for any chemical product that is used industrially to remove colour from (i.e. to whiten) fabric or fiber (in a process called bleaching) or to disinfect after cleaning. It frequently refers specifically to a dilute solution of sodium hypochlorite, also called liquid bleach.

Bleed – A bleed is defined as exudation of molten metal through a rupture in the skin. Liquid steel can penetrate until re-solidification takes place at the mould wall, i.e., bleeding’, false wall, or double skin, and, if steel flow is not stopped, result in a break-out. The bleeder is hence a ‘recovered’ or re-solidified sticker. Bleeding defect occurs when small strand break-out takes place, and healing immediately, without metal loss. It can be attributed to the effect of annular strain in hot zones, or sticking.

Bleed valves – These valves vent signal line pressure to atmosphere before removal of an instrument or to assist in calibration of control devices. Common bleed valves include ball and plug bleed valves.

Bleeder cloth – It is a woven or non-woven layer of material used in the manufacture of composite parts for allowing the escape of excess gas and resin during cure. The bleeder cloth is removed after the curing process and is not part of the final composite.

Bleeder valves – Bleeder valves are pressure relief valves or explosion prevention valves installed in bleeder pipe of furnace top pressure control systems. These valves are needed for controlling high top pressure at the blast furnace top and to protect the top of the furnace from sudden gas pressure surges.

Bleeding – It is separation of oil (or other fluid) from a grease. It is also the removal of excess resin from a laminate during cure. It is the diffusion of colour out of a plastic part into the surrounding surface or part.

Bleed-out – It is the excess liquid resin that migrates to the surface of a winding. It mainly occurs in filament winding.

Blended hydraulic cements – These are produced by intimately blending two or more types of cementitious materials. Primary blending materials are portland cement, ground granulated blast-furnace slag, fly ash, natural pozzolans, and silica fume. These cements are commonly used in the same manner as portland cements. Blended hydraulic cements are of following types. Type IS-portland blast-furnace slag cement, Type IP and Type P-portland pozzolana cement, Type S-slag cement, Type I (PM)-pozzolana modified portland cement, and Type I (SM)-slag modified portland cement. In Type IS the blast furnace slag content is between 25 % and 70 %. The pozzolana content of Types IP and P is between 15 % and 40 % of the blended cement. Type I (PM) contains less than 15 % pozzolana. Type S contains at least 70 % slag. Type I (SM) contains less than 25 % slag. These blended cements are also usually designated as air-entraining, moderate sulphate resistant, or with moderate or low heat of hydration. The blended hydraulic cements also include the following (i) type GU – blended hydraulic cement for general construction, (ii) type HE – high early strength cement, (iii) type MS – moderate sulphate resistant cement, (iv) type HS – high sulphate resistant cement, (v) type MH – moderate heat of hydration cement, and (vi) type LH – low heat of hydration cement. These cements can also be designated for low reactivity with alkali reactive aggregates. There are no restrictions as to the composition of these cements.

Blended sand – It is a mixture of sands of different grain size and clay content which provides suitable characteristics for foundry use.

Blending – It is the thorough intermingling of materials of the same nominal composition. Blending is the process of combining different materials to produce a new, uniform product. In lubrication, it is the process of mixing mineral oils to get the desired consistency. It is to be noted that blending is to be contrasted with compounding, which utilizes additives.

Blind flange – Blind flange does not have a bore. It is sometimes referred to as a blanking flange. This flange is used to blank off pipelines, valves and pumps. When used at the end of a pipe or fitting, it provides an easy to open access for further extension of the pipe.  It can also be used as an inspection cover. It is used to close the ends which need to be reopened later. The blind flange and its bolts are stressed more than any other flange.

Blind nipple – It is a nipple, or a short piece of pipe or tube, closed at one end.

Blind riser – It is a riser which does not extend through the top of the mould.

Blind sample – It is a sample submitted for analysis whose composition is known to the submitter but unknown to the analyst, used to test the efficiency of a measurement process.

Blister – It is a casting defect, on or near the surface of the metal, resulting from the expansion of gas in a sub-surface zone. It is characterized by a smooth bump on the surface of the casting and a hole inside the casting directly below the bump. In coating, it is a raised area, frequently dome shaped, resulting from loss of adhesion between a coating or deposit and the substrate. In extrusion, it is a raised area on the surface of an extruded product because of the sub-surface gas expansion. This condition can occur during extrusion or thermal treatment.

Blister, bond – It is a raised spot on only one surface of the metal whose origin is between the cladding and core in clad products.

Blister, coating – It is a blister in the coating of an alclad or a clad product.

Blister copper – It is an impure intermediate product in the refining of copper, produced by blowing copper matte in a converter, the name being derived from the large blisters on the cast surface which result from the liberation of sulphur di-oxide and other gases. It is a crude form of copper (assaying around 99 %) produced in a smelter, which needs further refining before being used for industrial purposes.

Blister, core – It is a raised spot (one or both sides) on rolled metal.

Blistering – It is the ‘process resulting in dome-shaped defect visible on the surface of an object and arising from localized loss of cohesion below the surface’. It is to be noted that ‘For example, blistering can occur on coated metal due to loss of adhesion between coating and substrate, caused by accumulation of products from localized corrosion. On uncoated metal, blistering can occur due to excessive internal hydrogen pressure’.

Bloating – In refractories, it consists of substantial swelling produced by a heat treatment which causes the formation of a vesicular structure.

Block – It is a preliminary forging operation which roughly distributes metal preparatory for finish. In refractories, a block is normally rectangular, refractory, usually of a larger size than a brick.

Block and bleed – It is the capability of obtaining a seal across the upstream seat of a valve when the body pressure is bled off to atmosphere through blow down valve or vent port.

Block and finish – It is the forging operation in which a part to be forged is blocked and finished in one heat through the use of tooling having both a block impression and a finish impression in the same die block.

Block diagram – It consists of vertically placed rectangles on a common base line, normally the height of the rectangles being proportional to a quantitative variable.

Blocker – It is the impression in the dies (frequently one of a series of impressions in a single die set) which imparts to the forging an intermediate shape, preparatory to forging of the final shape.

Blocker dies – These are forging dies having generous contours, large radii, draft angles of 7-degree or more, and liberal finish allowances.

Blocker-type forging – It is a forging which approximates the general shape of the final part with relatively generous finish allowance and radii. Such forgings are sometimes specified to reduce die costs where only a small number of forgings are described and the cost of machining each part to its final shape is not excessive.

Block flow diagram – It is a drawing of the process used to simplify and understand the basic structure of the process. It is the simplest form of the flow diagrams used in the industry. Blocks in this drawing can represent anything from a single piece of equipment to an entire plant. For a complex process, this drawing can be used to break up a complicated system into more reasonable principal stages / sectors. Block flow diagram is made for a process unit. It reflects (i) functional requirements of the unit, (ii) depicts the different processes carried out within the process unit and their sequence, and (iii) shows the inputs (feed) and outputs (products). It is used to explain the normal material flows throughout the entire plant. It is generalized to certain plant sectors or stages. The diagram helps orient operators to the products and important operation zones of a process facility.

Block foundation – It is used for equipments of large mass and a small natural frequency. The ability to use block foundation mainly depends on the quality of near surface soils and designed as rigid structures. The dynamic response of a rigid block foundation depends only on the dynamic load, foundation’s mass, dimensions, and soil characteristics. Majority of the normally used foundations in the industry are block foundations and frame foundations. In case of a block foundation, equipment is mounted over a solid block, normally made of concrete. This block in turn rests directly on the soil. In this case, both the equipment and the foundation block are considered as non-elastic inertia bodies and the soil is treated as mass-less elastic media i.e., having only stiffness and no inertia.

Block grease – It is a grease which is sufficiently hard to retain its shape in block or stick form.

Blocking – In forging, it is a preliminary operation performed in closed dies, normally hot, to position metal properly so that in the finish operation, the dies are filled correctly. Blocking can ensure proper working of the material and can increase die life.

Blocking impression – It is the impression which gives a forging its approximate shape.

Block plan – A block plan is the representation of a wider area which is in proximity to the main building under construction. A block plan can include the adjoining buildings, the roads, boundaries, and other such components. More importantly, a block plan is represented in scales, which also means that they cover a wide area. Block plans normally show the siting of a project in relation to survey maps.

Block sequence – It is a combined longitudinal and cross-sectional sequence for a continuous multiple-pass weld in which separated increments are completely or partially welded before intervening increments are welded.

Blocky alpha – It is alpha phase which is considerably larger and more polygonal in appearance than the primary alpha in the sample. It can arise from extended exposure high in the alpha-beta phase field or by slow cooling through the beta transus during forging or heat treating. It can be removed by beta recrystallization, or all-beta working, followed by further alpha-beta work, and can accompany grain-boundary alpha.

Bloom – Blooms can have a cross section either square or rectangular. Blooms with square cross section have sides having dimension higher than 160 mm. Rectangular-blooms have cross-sectional area higher than 25,600 square millimeters and have width to thickness ratio higher than 1 and less than 2. Steel blooms are sometimes made by forging. It is also a visible exudation or efflorescence on the surface of an electroplating bath. It is a bluish fluorescent cast to a painted surface caused by deposition of a thin film of smoke, dust, or oil. It is also a loose, flowerlike corrosion product which forms when certain metals are exposed to a moist environment. It is also a visible local exudation or finish change on the surface of a plastic. Bloom can be caused by a lubricant or plasticizer or by atmospheric contamination.

Blooming mill – This rolling mill is the preparatory mill to roll blooms from ingots. With the wide spread acceptance of continuous castings of blooms, this type of mill is no more needed.

Blow – It is a term which describes the trapping of gas in castings, causing voids in the metal.

Blow down – Blowing down of a blast furnace means running the blast furnace without charging until the burden level in the blast furnace is reduced to around the tuyere level. In boiler, it is the boiler water which is removed from the boiler in order to maintain the desired concentration levels of suspended and dissolved solids in the boiler and removal of sludge.

Blow-down safety valve – It is the difference between the pressures at which a safety valve opens and at which it closes.

Blow-down valve (BDV) – It is a small ball valve which is installed on the above-ground end of an extended drain line. This valve also serves to vent body cavity pressure in the ‘block and bleed’ mode. It is also a valve normally used to continuously regulate concentration of solids in the boiler. It is not a drain valve. (It is frequently called continuous blow-down).

Blower – It is a fan used to force air under pressure. It is a very important fluid machine. It has characteristics of energy transfer between continuous stream of fluid and rotating element about an axis. Blower is a head generating machine which employs the dynamic action of a rotating elements. Blowers are pressure increasing machines in which the fluid enters axially and is discharged by the rotor into a static collector system casing and then into a discharge pipe. They are also used to produce negative pressures for industrial vacuum systems. The centrifugal blower and the positive displacement blower are two main types of blowers. Blowers can achieve much higher pressures than fans, as high as 0.12 MPa.

Blowholes – Blowholes are small rounded cavities found at the surface or near surface of the cast products and these are caused by the entrapped gasses which are not able to escape during solidification. Blowholes are caused by gases released from the mould itself (external gases). During subsequent processing of the material these gas pockets get flattened or elongated or fused shut. Blowholes are mainly found in three forms namely (i) elongated cavities with smooth walls, found on or just below the surface of the top most part of castings and are caused by the entrapped air, (ii) round shaped cavities with smooth bright walls which are caused by mould or core gases, coupled with insufficient permeability or venting, and (iii) small cavities immediately below the ‘skin’ of the casting surface which are formed by the reaction of the liquid steel with the moisture in the moulding sand.

Blow in – Blow in is the process of starting a blast furnace after its construction or after its relining. The blow in process is carried out in several steps which consist of (i) drying out the lining, (ii) filling of the blast furnace with a specially arranged high coke blow in furnace charge, (iii) igniting of the coke or lighting of the blast furnace, and (iv) gradually increasing the hot blast with frequent castings to ensure the raising of temperature of the blast furnace hearth. During the period of blow-in, the burden ratio (ratio of the ore to coke) is adjusted according to a pre-determined schedule until the normal operation of the blast furnace is achieved.

Blow moulding – It is a method of fabricating plastics in which a warm plastic parison (hollow tube) is placed between the two halves of a mould (cavity) and forced to assume the shape of that mould cavity by use of air pressure. The air pressure is introduced through the inside of the parison and forces the plastic against the surface of the mould, which defines the shape of the product.

Blow pin – It is the part of the tooling which is used to form hollow objects by the blow moulding process. It is a tubular tool through which air pressure is introduced into the parison to create the air pressure necessary to form the parison into the shape of the mould. On some blow moulding systems, it is a part of, or an extension of, the core pin.

Blow-off valve – It is a specially designed, manually operated, valve which connects to the boiler for the purpose of reducing the concentration of solids in the boiler or for draining purposes. (It is frequently called bottom blow-down).

Blown oil – It is the fatty oil which is artificially thickened by blowing air through it.

Blow out – The blowing out is also called sometimes raking out. Blast furnace is normally blown out when the production from the blast furnace is no longer needed. The blow out is done after the installation of blow out equipment and following the blow out procedure.

Blow out(s) – These are the areas adjacent to unsealed overlapping surfaces which have been affected by pre-treatment solutions boiling out of the overlap area.

Blow pipe – The blowpipe is an inte­gral component of the hot blast system of the blast furnace. Positioned between the bustle pipe down-leg and tuyere, the blowpipe is normally a two-piece component, consisting of an elbow and a cone section, and is typically constructed with an outer steel shell lined with a two-component refractory system.

Blue annealing – It consists of heating hot-rolled ferrous sheet in an open furnace to a temperature within the transformation range and then cooling in air, in order to soften the metal. The formation of a bluish oxide on the surface is incidental.

Blue brittleness – It is the brittleness shown by some steels after being heated to some temperature within the range of around 205 deg C to 370 deg C, particularly if the steel is worked at the elevated temperature. Killed steels are virtually free of this kind of brittleness.

Blue dip – It is a solution containing a mercury compound, once widely used to deposit mercury on a metal by immersion, normally prior to silver plating.

Blue dust – It is also known as blue ore or blue powder. It is a type of high-grade iron ore which typically contains more than 65 % iron content. It gets its name from its bluish appearance when finely ground or in powdered form. Blue Dust is mainly composed of hematite, martite and goethite while quartz and kaolinite are the gangue minerals. Silica removal is the primary control of iron enrichment.

Blue enamel – In dry-process enameling, it is an area of enamel coating so thin that it appears blue in colour. In wet-process enameling, it is a cover coat applied too thinly to hide the substrate.

Blue hydrogen – The second-most-common process, blue hydrogen, relies on the same basic processes as gray hydrogen, but it traps up to 90 % of the greenhouse gas emissions through carbon capture, utilization and storage technology. In some cases, this carbon is stored underground. The underground storage needs considerable capital costs. Or it is reused as a feedstock for industrial applications, in which carbon di-oxide is still ultimately released into the atmosphere. Blue hydrogen has limitations which have so far restricted its deployment. These limitations include (i) use of finite resources, (ii) exposed to fossil fuel price fluctuations, and (iii) does not support the goals of energy security.

Blueprint – It is the common shop term for a detailed engineering drawing giving dimensions and manufacturing details for a part. The term comes from an early printing process which gave a drawing with white lines on a blue background.

Bluing – It consists of subjecting the scale-free surface of a ferrous alloy to the action of air, steam, or other agents at a suitable temperature, thus forming a thin blue film of oxide and improving the appearance and resistance to corrosion. This term is ordinarily applied to sheet, strip, or finished parts. It is used also to denote the heating of springs after fabrication to improve their properties.

Blushing – It is whitening and loss of gloss of a normally organic coating caused by moisture. It is also called blooming. It is also the condensation of atmospheric moisture at the adhesive bond line interface.

Board hammer – It is a type of forging hammer in which the upper die and ram are attached to ‘boards’ which are raised to the striking position by power-driven rollers and let fall by gravity.

Boat – It is a box container used for holding the green compacts during passage through a continuous sintering furnace.

Bobbing compound – It is a compound used for heavy buffing which normally contains some form of coarse silica such as flint or quartz. It is considerably more abrasive than tripoli compound.

Body-centered – It means having an atom or group of atoms separated by a translation of 1/2, 1/2, 1/2 from a similar atom or group of atoms. The number of atoms in a body-centered cell must be a multiple of 2.

Body centred cubic (bcc) structure – The term “body-centered cubic” (BCC) refers to a particular sort of atom arrangement found in nature. A body-centered cubic unit cell structure is composed of atoms organized in a cube with one atom in each corner and one atom in the center. Eight other unit cells share the atom at the cube’s corners.

Body-centred tetragonal (bct) structure – It is a crystal structure with 8 atoms forming the corners of a tetragon (elongated or shortened cube), and one atom in the centre. It is the structure of martensite which is essentially the body centred cubic austenite structure distorted by interstitial carbon atoms into a tetragonal lattice.

Body relief valve (BRV) – It is a relief valve installed on double-seated valves used in liquid service to provide for the relief of excess body pressure caused by thermal expansion.

Body, valve – It is the principal pressure containing part of a valve, in which the closure element and the seats are located.

Body putty – It is a paste-like mixture of plastic resin (polyester or epoxy) and talc used in repair of metal surfaces, such as auto bodies.

Bog – It is a wetland characterized by peat deposits, acidic water, and extensive surface mats of sphagnum moss. Bogs receive their water from precipitation rather than from runoff, groundwater, or streams, with decreases the availability of nutrients needed for plant growth.

Bogie – It is a chassis or framework which carries a wheelset. It is attached to a vehicle, a modular sub-assembly of wheels and axles. Bogies take different forms in different modes of transport.

Bog iron – It is a form of impure iron deposit that develops in bogs or swamps by the chemical or biochemical oxidation of iron carried in solution. In general, bog ores consist primarily of iron oxyhydroxides, commonly goethite [FeO(OH)].

Bohr model – It is model of the general structure of the atom, featuring a small, dense nucleus of positively charged particles surrounded by orbiting electrons, which are attracted to the nucleus by electrostatic forces. This interpretation replaced several earlier hypotheses and quickly became the prevailing standard model for depicting atomic structure.

Boil – It is agitation of a bath of metal caused by the liberation of a gas beneath its surface. It can be deliberately induced by the addition of oxidizing material to a bath containing excess carbon. In the latter case, it is called a carbon boil and carbon mono oxide or carbon di-oxide are liberated.

Boiler – It is a closed vessel in which water is heated, steam is generated, steam is superheated, or any combination thereof, under pressure or vacuum by the application of heat from combustible fuels, electricity, or nuclear energy.

Boiler efficiency – The term boiler efficiency is frequently substituted for combustion or thermal efficiency. True boiler efficiency is the measure of fuel-to-steam efficiency.

Boiler failure – Boiler failure is a term normally applied to the pressurized parts of the boiler. A ruptured tube or a crack which allows high-pressure steam or water to escape to the point of the boiler needing a shut-down is considered a boiler failure.

Boiler feed water – It is used for steam generation in a boiler. Raw waters must be pretreated to meet the water quality requirements needed by the boiler for steam making. Such treatment typically involves filtration, hardness removal (softening) and/or silica reduction, deaeration, and pH/alkalinity adjustment. If improperly conditioned, water-related problems, including mineral precipitation and corrosion, can result in permanent damage to the steam generating unit along with energy inefficient operation.

Boiler horse-power – Boiler horse-power is the capacity of a boiler to deliver steam. One boiler horse-power is equal to the thermal energy rate needed to evaporate 15.6 kg of fresh water at 100 deg C in one hour into dry saturated steam at the same temperature.

Boiler quality steel – It is the steel used in boilers, pressure vessels and for steam application. It is a high tensile carbon steel with consistent quality and is designed to withstand high pressure.

Boiler shell – It is the outer cylindrical portion of a pressure vessel.

Boiler water – It is a term construed to mean a representative sample of the circulating boiler water, after the generated steam has been separated and before the incoming feed water or added chemical becomes mixed with it so that its composition is affected.

Boiling – It is the conversion of a liquid into vapour with the formation of bubbles.

Boiling flask – It is a type of flask used as an item of laboratory glassware. It is used as a container to hold liquids. It has a round body, a long neck, and frequently a flat bottom. It is designed for uniform heating, boiling, distillation and ease of swirling. it is frequently made of borosilicate glass for heat and chemical resistance. The common volume for a boiling flask is 1 litre.

Boiling out – It is the boiling of highly alkaline water in boiler pressure parts for the removal of oils, and greases etc.

Boiling point – It is the temperature (100 deg C) at which water boils. Water boils when its absolute pressure reaches the vapour pressure.

Boiling water reactor – It is a reactor design where water is allowed to boil in the core. The resulting steam is used to drive a turbine and electrical generator, thereby producing electricity. Decommissioning boiling water reactors has to take into account the radioactivity of the turbines resulting from leakage from fuel elements into the water and hence the steam which is in direct contact with the turbines.

Bolster plate – It is a plate to which dies can be fastened, the assembly being secured to the top surface of a press bed. In mechanical forging, such a plate is also attached to the ram.

Bolt – It is a fastener which is comprised of a screw and a nut.

Bolt circle – It is the circle on which bolt holes are located. It is the dimension of a circle of tapped or through holes on a valve top flange or actuator mounting plate for securing the two devices.

Bolted bonnet – It is the top part of a valve joined to the body which guides the stem and adapts to extensions or operators.

Bolted construction – It describes a valve construction in which the pressure shell elements are bolted together and hence can be taken apart and repaired in the field.

Bolting sets – It consists of bolts or studs and nuts which are sometimes supplied with flanged valves to install the valve between line flanges.

Boltzmann distribution – It is a function giving the probability that a molecule of a gas in thermal equilibrium will have generalized position and momentum coordinates within a given infinitesimal range of values, assuming that the molecules obey classical mechanics.

Bomb calorimeter – It is a type of constant-volume calorimeter used in measuring the heat of combustion of a particular reaction. Bomb calorimeters have to withstand the large pressure within the calorimeter as the reaction is being measured. Electrical energy is used to ignite the fuel. As the fuel is burning, it heats up the surrounding air, which expands and escapes through a tube that leads the air out of the calorimeter. When the air is escaping through the copper tube it also heats up the water outside the tube. The change in temperature of the water allows for calculating calorie content of the fuel.

Bond – It consists of (i) bonding substance or bonding agents, which is any material other than water, which, when added to foundry sands, imparts bond strength, and (ii) it is the overlapping of brick so as to give both longitudinal and transverse strength. In grinding wheels and other relatively rigid abrasive products, It is the material which holds the abrasive grains together. In welding, brazing, or soldering, it is the junction of joined parts. Where filler metal is used, it is the junction of the fused metal and the heat-affected base metal. In an adhesive-bonded or diffusion-bonded joint, it is the line along which the faying surfaces are joined together. In thermal spraying, it is the junction between the material deposited and the substrate, or its strength.

Bond clay – It consists of any clay suitable for use as a bonding agent in moulding sand.

Bond coat – In thermal spraying, it is a preliminary (or prime) coat of material which improves adherence of the subsequent thermal spray deposit.

Bonded-phase chromatography – It is the liquid chromatography with a surface-reacted, i.e., chemically bonded, organic stationary phase.

Bonded solid lubricant – It is a solid lubricant dispersed in a continuous matrix of a binder, or attached to a surface by an adhesive material.

Bond fireclay – It is a fireclay of sufficient natural plasticity to bond non-plastic materials.

Bonding agent – It is any material other than water which, when added to foundry sands, imparts strength either in the green, dry, or fired state.

Bonding force – It is the force which holds two atoms together. It results from a decrease in energy as two atoms are brought closer to one another.

Bond line – It is the cross section of the interface between thermal spray deposits and substrate, or between adhesive and adherend in an adhesive bonded joint.

Bond strength – It is the strength with which two or more items are joined. It is the resistance which is to be overcome in order to separate the joined materials, e.g. steel and zinc-iron alloy layers of the galvanized coating, or galvanized reinforcement steel and concrete.

Bone oil – It is a fatty oil obtained by dry distillation of bone.

Bonferroni post-hoc test – It is a multiple- comparison procedure allowing the person carrying out the study to test differences between pairs of group means without incurring capitalization on chance.

Bonnet – The cover for the opening in the valve body is the bonnet, and it is the second most important boundary of a pressure valve. Like valve bodies, bonnets are available in several designs and models. In some designs, the body itself is split into two sections which bolt together. Bonnets vary in design. Some bonnets function simply as valve covers, while others support valve internals and accessories such as the stem, disk, and actuator. During manufacture of the valve, the internal components, such as stem, and disk etc., are put into the body and then the bonnet is attached to hold all the components together inside.

Book mould – It is a split permanent mould hinged like a book.

Boolean operation – In solid modeling, it needs three operators for combining sets of objects. The operators are union (+), difference (-), and intersection (*).

Boom – A material handler boom is a piece of equipment designed to lift, move, and place materials in different settings. It consists of a boom arm, which is either fixed or telescopic, and a hydraulic system which provides the necessary power to handle heavy loads.

Booster – It is a device used to increase voltage on an electric power distribution system, such as a motor-generator set on a direct current system.

Booster fan – It is a device for increasing the pressure or flow of a gas.

Bore – It is a hole or cylindrical cavity produced by a single-point or multipoint tool other than a drill. In case of valves, it is the inside diameter of the smallest opening through a valve such as the diameter of the hole in the ball of a ball valve, the diameter of the hole in the gate of a gate valve, and the inside diameter of seat rings. It is also known as port.

Borescope – It is a long, tubular optical device which illuminates and allows the inspection of surfaces inside narrow tubes or difficult-to-reach chambers. The tube, which can be rigid or flexible with a wide variety of lengths and diameters, provides the necessary optical connection between the viewing end and an objective lens at the distant, or distal, tip of the borescope. This optical connection can be achieved in one of three different ways namely (i) by using a rigid tube with a series of relay lenses, (ii) by using a tube (normally flexible but also rigid) with a bundle of optical fibers, and (iii) by using a tube (normally flexible) with wiring that carries the image signal from a charge-coupled device (CCD) imaging sensor at the distal tip.

Bore seal – It is a device in which the outside diameter mates with a bore surface to provide sealing between the two surfaces.

Borides – A boride is a compound between boron and a less electronegative element, for example silicon boride (SiB3 and SiB6). The borides are a very large group of compounds which are normally high melting and are covalent more than ionic in nature. Some borides show very useful physical properties.

Boriding or boronizing – It is the thermo-chemical treatment involving the enrichment of the surface layer of an object with borides. This surface-hardening process is performed below the Ac1 temperature.

Boring – It is enlarging a hole by removing metal with a single- or occasionally a multiple-point cutting tool moving parallel to the axis of rotation of the work or tool. It is a machining method using single point tools on internal surfaces of revolution.

Boron – Boron (atomic number 5 and atomic weight 10.81) has density of 2.34 grams per cubic metre. Its melting point is 2,076 deg C and boiling point is 3,927 deg C. It is a solid material at the atmospheric pressure and at 0 deg C temperature. It is useful as an alloying element in the steel because of its effect on hardenability enhancement. It has no effect on the strength of normal hot rolled steel but can considerably improve hardenability when transformation products such as acicular ferrite are desired in low C hot-rolled steel plate. Its full effect on hardenability is achieved only in fully deoxidized (aluminum killed) steels. It is added to carbon and low alloyed steels at concentration levels of 0.0015 % to 0.0030 % for increasing the hardness level through the enhancement of hardenability.

Boron fibre – It is a fibre which is produced by vapour deposition of elemental boron, normally onto a tungsten filament core, for imparting strength and stiffness.

Boron steels – These are steels which contain boron normally in the range of 0.002 % to 0.003 %. Boron is added to increase the hardenability of the steel.

Bort – It is natural diamond of a quality not suitable for gem use. It is industrial diamond.

Bosh – It is an intermediate zone in the blast furnace, situated between the hearth and the belly of the furnace. It is the section of a blast furnace extending upward from the tuyeres to the plane of maximum diameter. It is a lining of quartz which builds up during the smelting of copper ores and which decreases the diameter of the furnace at the tuyeres. It is also a tank, frequently with sloping sides, used for washing metal parts or for holding cleaned parts.

Bosh angle – It is the acute angle formed by a horizontal line and the slope of the bosh.

Bosh diameter – It is the diameter of the inside of the lining at the bosh line. It is also the diameter of the straight section or belly above the bosh.

Bosh line – It is the horizontal line at the intersection of the slope of the bosh and the belly. In case there is no belly in a blast furnace then the bosh line is at the intersection of the slope of the bosh and the batter of the in-wall.

Boss – It is a relatively short protrusion or projection from the surface of a forging or casting, frequently cylindrical in shape. It is normally intended for drilling and tapping for attaching parts.

Bottle – It is a non-standard term for gas cylinder.

Bottom board – In casting, it is a flat base for holding the flask in making sand moulds.

Bottom blowing process – In this process, oxygen is injected with lime through nozzles, or tuyeres, located in the bottom of the vessel. The tuyeres consist of two concentric tubes. Oxygen and lime are introduced through the inner tube, and a hydrocarbon such as natural gas is injected through the outer annulus.

Bottom draft -It is the slope or taper in the bottom of a forge depression which tends to assist metal flow toward the sides of depressed areas.

Bottom drill – It is a flat-ended twist drill used to convert a cone at the bottom of a drilled hole into a cylinder.

Bottom in-wall line – It is the horizontal line through the intersection of the vertical line of the belly and the in-wall batter. In furnaces with no belly portion the bottom in-wall line coincides with the bosh line.

Bottoming bending – It is the press-brake bending process in which the upper die (punch) enters the lower die and coins or sets the material to eliminate spring back .

Bottoming tap – It is a tap with a chamfer of 1 to 1 thread in length.

Bottom pipe – It is an oxide-lined fold or cavity at the butt end of a slab, bloom, or billet; formed by folding the end of an ingot over on itself during primary rolling. Bottom pipe is not pipe, in that it is not a shrinkage cavity, and in that sense, the term is a misnomer. Bottom pipe is similar to extrusion pipe. It is normally discarded when the slab, bloom, or billet is cropped following primary reduction.

Bottom-pour ladle – It is a ladle from which metal, normally steel, flows through a nozzle located at the bottom.

Bottom pouring – It is filling of the mould cavity from the bottom by means of gates from the runner.

Bottom punch – It is the part of the tool assembly which closes the die cavity at the bottom and transfer the pressure to the powder during compaction.

Boudouard reaction – It is the redox reaction of a chemical equilibrium mixture of carbon mono-oxide and carbon di-oxide at a given temperature. It is the disproportionation of carbon mono-oxide into carbon dioxide and graphite or its reverse. The Boudouard reaction to form carbon di-oxide and carbon is exothermic at all temperatures. However, the standard enthalpy of the Boudouard reaction becomes less negative with increasing temperature.

Boundary grain – In the Jeffries’ method for grain size measurement, a grain which is intersected by the boundary of the standard area and is hence counted only as one half of a grain.

Boundary lubricant – It is a lubricant which is suitable for use in boundary lubrication conditions. Fatty acids and soaps are normally used.

Boundary lubrication – It is a condition of lubrication in which the friction and wear between two surfaces in relative motion are determined by the properties of the surfaces and by the properties of the lubricant other than bulk viscosity. It is to be noted that several circumstances which at one time have been referred to as boundary lubrication can be elasto-hydrodynamic.

Bound charge – It is an electric charge in a material which is not free to move through the material.

Boyle’s law – It is an empirical gas law which describes the relationship between pressure and volume of a confined gas. Boyle’s law has been stated as the absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and quantity of gas remain unchanged within a closed system.

Bow – It is a defect in sheet metal. If the sheet metal is no longer flat, with edges or the middle section raised then bowing has occurred. It occurs because of the cutting angle or even the strength or quality of the plate itself. Sometimes a smaller shearing angle or improved back support can rectify the problem. It is also a longitudinal curvature of rod, bar, profiles (shapes), and tube. Bow is measured after allowing the weight of the extrusion to minimize the deviation. Bow can be caused by a non-uniform extrusion rate across the cross section, resulting in one portion of the extrusion being longer than the other or nonuniform contraction during quenching..

Bowing – It is deviation from flatness.

Bow, lateral – It is deviation from straight of a longitudinal edge.

Bow, longitudinal – It is curvature in the plane of sheet or plate in the rolling direction.

Bow, transverse – It is curvature across the rolling direction of sheet or plate.

Box annealing – It is annealing a metal or alloy in a sealed container under conditions which minimize oxidation. In box annealing a ferrous alloy, the charge is normally heated slowly to a temperature below the transformation range, but sometimes above or within it, and is then cooled slowly. This process is also called close annealing or pot annealing.

Box equipment foundation – It is used in the cases of less mass with higher natural frequency equipments. Because of hollow concrete block. The mass of this foundation is less than block type foundation as it is hollow. The natural frequency of the box type foundation is increased.

Box furnace – It is a furnace used for batch sintering, normally utilizing a controlled atmosphere containing sealed retort.

Boxing – It is the continuation of a fillet weld around a corner of a member as an extension of the principal weld.

Box piles – A steel pile, assembled from sheet piles to form a hollow box in cross section. Box piles are formed by welding two or more sheet pile sections together. Both ‘U’ and ‘Z’ sheet pile sections can be used. They can be introduced into a line of sheet piling at any point where local heavy loads are to be applied, for instance beneath bridge beams, or used separately.

Box plot – It is also called box and whisker plot and the box-and-whisker diagram. It is a graphical representation of numerical data, based on the five-number summary. It is a method for demonstrating graphically the locality, spread and skewness groups of numerical data through their quartiles. In addition to the box on a box plot, there can be lines (which are called whiskers) extending from the box indicating variability outside the upper and lower quartiles. Any values beyond the ends of the whiskers are shown individually as outliers. Sometimes any values further than 3 times the interquartile range are indicated with a different symbol as extreme outliers. The diagram has a scale in one direction only. A rectangular box is drawn, extending from the lower quartile to the upper quartile, with the median shown dividing the box. ‘Whiskers’ are then drawn extending from the end of the box to the greatest and least values. Outliers which differ considerably from the rest of the dataset can be plotted as individual points beyond the whiskers on the box-plot. Box plots are non-parametric. They display variation in samples of a statistical population without making any assumptions of the underlying statistical distribution. The spacings in each sub-section of the box-plot indicate the degree of dispersion (spread) and skewness of the data, which are normally described using the five-number summary. In addition, the box-plot allows one to visually estimate various L-estimators, notably the interquartile range, midhinge, range, mid-range, and trimean. Box plots can be drawn either horizontally or vertically. Multiple boxplots, arranged side by side, can be used for the comparison of several samples. In refined boxplots, the whiskers have a length not exceeding 1.5 times the interquartile range.

Braced frame – A braced frame is a very strong structural system which is normally used in structures subject to lateral loads such as wind and seismic pressure. The members in a braced frame are normally made of structural steel, which can work effectively both in tension and compression. The beams and columns which form the frame carry vertical loads, and the bracing system carries the lateral loads. The positioning of braces, however, can be problematic since they can interfere with the design of the facade and the positioning of openings.

Bracing – It is the metal which is attached to a fabrication prior to galvanizing in order to provide support so that the steel does not change shape during heating and cooling. It can be temporary or permanent. In structures, bracings are pinned connections between beams and columns. Bracing, which provides stability and resists lateral loads, can be from diagonal steel members or, from a concrete ‘core’. In braced construction, beams and columns are designed under vertical load only, assuming the bracing system carries all lateral loads.

Bracing system – It is a secondary but essential part of a structure. A bracing system serves to stabilize the main girders during construction, to contribute to the distribution of load effects and to provide restraint to compression flanges or chords where they would otherwise be free to buckle laterally.

Brackish water – It is the water having salinity values ranging from approximately 0.5 parts per thousand to 17 parts per thousand. It is the water having less salt than seawater, but not drinkable.

Bragg angle – It is the angle between the incident beam and the lattice planes considered.

Bragg equation – This equation is n.lambda = 2d.sin(theta), where ‘n’ is the order of reflection, lambda is the wavelength of x-rays, d the distance between lattice planes, and theta is the Bragg angle.

Bragg’s law – It is a statement of the conditions under which a crystal diffracts electro-magnetic radiation. Bragg’s law reads n.lambda = 2d.sin(theta), where ‘n’ is the order of reflection, lambda is the wavelength of x-rays, d the distance between lattice planes, and theta is the Bragg angle or the angular distance between the incident beam and the lattice planes considered.

Bragg method – It is a method of x-ray diffraction in which a single crystal is mounted on a spectrometer with a crystal face parallel to the axis of the instrument.

Braid – It is a system of three or more yarns which are inter-woven in such a way that no two yarns are twisted around each other.

Braided slings – These are normally fabricated from six to eight small diameter ropes braided together to form a single rope which provides a large bearing surface, very high strength, and flexibility in every direction. They are easy to handle and almost impossible to kink. The braided sling can be used in all the standard configurations and combinations but is especially useful for basket hitches where low bearing pressure is desirable or where the bend is extremely sharp.

Braiding – It is weaving of fibres into a tubular shape instead of a flat fabric, as for graphite- fiber-reinforced golf club shafts. It is also textile process where two or more strands, yarns, or tapes are intertwined in the bias direction to form an integral structure.

Brain-storming – It is a technique used by teams to generate ideas on a subject. Each person on the team is asked to think creatively and suggest as many ideas as possible. No criticism or discussion of the ideas is allowed until after the brain-storming session.

Brake – It is a device for bending sheet metal to a desired angle.

Brale indenter – It is a conical 120-degree diamond indenter with a conical tip (a 0.2 mm tip radius is typical) used in certain types of Rockwell and scratch hardness tests.

Branch – It is a line in a PERT (programme evolution review technique) network indicating an activity or precedence. It is also called an arc.

Branched polymer – In molecular structure of polymers, it is a main chain with attached side chains, in contrast to a linear polymer.

Brass – It is a copper-zinc alloy containing up to 40 % zinc, to which smaller quantities of other elements can be added.

Braze – It is a weld produced by heating an assembly to suitable temperatures and by using a filler metal having a liquidus temperature above 450 deg C and below the solidus temperature of the base metal. The filler metal is distributed between the closely fitted faying surfaces of the joint by capillary action.

Brazeability – It is the capacity of a metal to be brazed under the fabrication conditions imposed into a specific suitably designed structure and to perform satisfactorily in the intended service.

Braze interface – It is the interface between filler metal and base metal in a brazed joint.

Brazement – It is an assembly whose component parts are joined by brazing.

Brazer – A person who performs a manual or semi-automatic brazing operation.

Braze welding – It is a welding process variation in which a filler metal having a liquidus temperature above 450 deg C and below the solidus temperature of the base metals is used. Unlike brazing, in braze welding, the filler metal is not distributed in the joint by capillary attraction.

Brazing – It is a group of welding processes which join solid materials together by heating them to a suitable temperature and using a filler metal having a liquidus temperature above 450 deg C and below the solidus temperature of the base materials. The filler metal is distributed between the closely fitted surfaces of the joint by capillary attraction.

Brazing alloy – It is sometimes used for the term brazing filler metal.

Brazing filler metal – It is the metal which fills the capillary gap and has a liquidus temperature above 450 deg C but below the solidus temperature of the base materials. It is a non-ferrous filler metal used in brazing and braze welding.

Brazing operator – A person who operates machine or automatic brazing equipment.

Brazing rod – It is a rolled, extruded, or cast round filler metal for use in joining by brazing.

Brazing sheet – It is the sheet of a brazing alloy or sheet clad with a brazing alloy on one or both sides.

Brazing wire – It is a wire for use as a filler metal in joining by brazing.

Break-away force, magnet – it is the force needed to separate the load from the magnet when pulled in a direction perpendicular to the magnet’s face. The breakaway force of a lifting magnet is proportional to the thickness of the material being lifted. A magnet’s breakaway force increases until the material being lifted exceeds the saturation thickness. Accordingly, thinner materials do not yield as high a breakaway force while thicker materials do not yield a greater breakaway force.

Break-away thrust, break-away torque – It is the thrust or torque required for moving a valve from the fully closed position and under a pressure differential.

Break-down – It is an initial rolling or drawing operation, or a series of such operations, for the purpose of reducing a casting or extruded shape prior to the finish reduction to desired size. It is also a preliminary press-forging operation. In case of equipment, it refers to any machine, part, or system failure or malfunction, which results in a stoppage of production or service and an impact on the operations.

Break-down maintenance – It is also known as reactive maintenance or run-to failure maintenance. It basically consists of running the equipment till it breakdown. No actions are taken or efforts are made to maintain the equipment till the failure of the equipment. In this type of maintenance strategy, the maintenance action is taken up when the equipment breaks down completely and needs repair to resume operation. Sometimes breakdown maintenance is the default maintenance strategy, relying on reactive maintenance. The breakdown maintenance strategy is preferable where repair of the equipment is simple and easier, and where preventive maintenance carried out in stopping or disrupting normal production runs is very costly.

Break-down potential – It is the last noble potential where pitting or crevice corrosion, or both, initiates and propagates.

Break-even analysis – It is an economic analysis in which costs are determined as a function of units of output or volume of production. The break-even point (minimum batch size) occurs at the number of units for which the revenues equal the total costs.

Break in – It means to operate a newly installed bearing, seal, or other tribo-component in such a manner as to condition its surface(s) for improved functional operation.

Breaking extension – It is the elongation necessary to cause rupture of a test sample. It is also the tensile strain at the moment of rupture.

Breaking factor – It is the breaking load divided by the original width of a test sample, expressed in kilogram per centimeter.

Breaking length – It is a measure of the breaking strength of yarn. It is the length of a sample whose weight is equal to the breaking load.

Breaking load – It is the maximum load (or force) applied to a test sample or structural member loaded to rupture.

Breaking stress – It is the stress at failure. It is also known as the rupture stress, or as the fracture stress.

Break out – A ‘breakout’ is the term used to denote the conditions and results of the escape of gas and coke, or slag, or iron, from the bosh, tuyere breast, or hearth of a blast furnace. Breakout can occur at any point below the fusion zone in the furnace, but the most of the severe breakouts are of liquid slag and of liquid iron. Liquid iron breakout takes place at a level below the surface of iron lying in the hearth, and are either through the hearth walls and jacket or into the hearth bottom and out under the hearth jacket. In continuous casting machine, breakout occurs when solidifying strand steel shell ruptures or tears beneath the mould. It is the most detrimental incident associated with the process of continuous casting. It is also a fibre separation or break on surface plies at drilled or machined edges.

Breaks – These are creases or ridges normally in ‘untempered’ or in aged material where the yield point has been exceeded. Depending on the origin of the breaks, they can be termed cross breaks, coil breaks, edge breaks, or sticker breaks.

Breast cooler – It is the circular cooler fixed on the furnace shell on which normally intermediate cooler and tuyere is mounted. Breast cooler is water cooled.

Breather – It is a loosely woven material which serves as a continuous vacuum path over a part but is not in contact with the resin.

Breathing – It is the opening and closing of a mould to allow gas to escape early in the moulding cycle. It is also called degassing. It is sometimes called bumping, in phenolic moulding.

Breeching – It is a duct which transports the products of combustion between parts of a steam generating unit or to the stack.

Breeder reactor – It is a reactor designed to produce more fuel (fissile material) than it consumes.

Brick – It is a refractory brick which is a block of ceramic material used in lining furnaces, and kilns. A refractory brick is built primarily to withstand high temperature, but also normally has a low thermal conductivity for higher energy efficiency. Brick is normally rectangular refractory with one dimension larger than the other two and of a size which can normally be laid with one hand.

Brick patching – This technique is normally used for building up the eroded bottom. After steel tapping and slag tapping is over, some slag is kept in the converter. Coarse or broken spent converter refractory bricks are added to the liquid slag. A total of 30 minutes to 60 minutes extra time is needed to accomplish the solidification of the slag. The spent refractory is to be coarse to be able to reinforce the liquid slag.

Brickwork – It is a masonry work by a bricklayer, using bricks and mortar. Typically, rows of bricks—called courses are laid on top of one another to build up a structure such as a brick wall.

Bridge – It is the main travelling structure of the crane and spans the width of the building bay. It travels in a direction parallel to the runway. The bridge consists of two end trucks and one or two bridge girders depending on the equipment type. The bridge also supports the trolley and hoisting mechanism for the up and down lifting of the load.

Bridge die – It is a two-section extrusion die capable of producing tubing or intricate hollow shapes without the use of a separate mandrel. Metal separates into two streams as it is extruded past a bridge section, which is attached to the main die section and holds a stub mandrel in the die opening, the metal then is rewelded by extrusion pressure before it enters the die opening.

Bridge girder(s) – A bridge girder is the principal horizontal beam of the crane bridge which supports the trolley and is supported by the end trucks.

Bridge type bucket wheel reclaimer – This type of reclaimer utilizes two bucket wheels mounted so that they rotate around a bridge which travels up and down the stockpile. For reclaiming across the face of the stockpile, the bucket wheel systems travel along the bridge.

Bridge type scraper reclaimer – A bridge type scraper reclaimer is necessary, where reclaiming is to be carried out from the face of a stockpile for blending. The bridge reclaimer is named after the reclaimer body connecting the two end bogies (carriages). In this reclaimer, a scraper chain system is mounted on the bridge type structure. The structure of the reclaimer spans from one end bogie to the other and is a bridge like beam which is parallel to the ground.

Bridge wall – It is a wall in a furnace over which the products of combustion pass.

Bridging – It is premature solidification of metal across a mould section before the metal below or beyond solidifies. It is also the solidification of slag within a cupola at or just above the tuyeres. It is welding or mechanical locking of the charge in a down feed melting or smelting furnace. In powder metallurgy, it is the formation of arched cavities in a powder mass. In soldering, it is an unintended solder connection between two or more conductors, either securely or by mere contact.

Bridging document – It is a document which explains the relationship between UNFC and another classification system, including instructions and guidelines on how to classify estimates generated by application of that system using the ‘UNFC Numerical Codes’.

Bridle hitch – Two, three or four single hitches can be used together to form a bridle hitch for hoisting an object with the necessary lifting lugs or attachments. Bridle hitch, which is used with a wide assortment of end fittings, provides outstanding load stability when the load is distributed equally among the legs, the hook is directly over the load’s centre of gravity and the load is raised level. For the distribution of the load equally, it is necessary to adjust the leg lengths with turnbuckles. Proper use of a bridle hitch requires that sling angles be carefully measured to ensure that individual legs are not overloaded.  When a four-leg sling lifts a rigid load, it is to be assumed that the load is carried by two of the legs only and the ‘rate’ of the four-leg sling is that of a two leg sling. This is because the load may not be distributed evenly.

Bright annealing – It consists of annealing in a protective medium to prevent discolouration of the bright surface. The process is carried out normally in a controlled furnace atmosphere, so surface does not oxidize, remaining bright.

Bright dip – It is a solution which produces, through chemical action, a bright surface on an immersed metal.

Bright stock – It consists of high-viscosity mineral oils which remain after vacuum distillation of crude oil.

Brightener – It is an agent or combination of agents added to an electroplating bath to produce a lustrous deposit.

Bright-field illumination – For reflected light, it is the form of illumination which causes specularly reflected surfaces normal to the axis of the microscope to appear bright. For transmission electron microscopy, it is the illumination of an object so that it appears on a bright background.

Bright finish -It is a high-quality finish produced on ground and polished rolls. The majority of tools are finished with a ground or mechanically polished surface which is normally categorized as a bright finish. Bright finished tools are frequently preferred to tools with an oxide finish for machining non-ferrous materials. The smooth or bright finish tends to resist galling, a type of welding or build-up associated with several non-ferrous materials. However, ferrous materials tend to adhere to similar, iron-based tools having a bright finish. This build-up on the cutting edges leads to increased frictional heat, poor surface finish, and increased load at the cutting edge. Bright finish is suitable for electroplating.

Bright nitriding – It consists of nitriding in a protective medium to prevent discoloration of the bright surface.

Bright plate – It is an electrodeposit which is lustrous in the as-plated condition.

Bright-throwing power – It is the measure of the ability of a plating solution or a specified set of plating conditions for depositing uniformly bright electroplate on an irregularly shaped cathode

Brine – It is seawater containing a higher concentration of dissolved salt than that of the ordinary ocean.

Brine quenching – It is a quench in which brine (salt water-chlorides, carbonates, and cyanides) is the quenching medium. The salt addition improves the efficiency of water at the vapour phase or hot stage of the quenching process.

Brinell hardness – It is a number related to the applied load and to the surface area of the permanent impression made by a ball indenter. It is the value of hardness of a metal on an arbitrary scale representing kilograms per square millimeter, determined by measuring the diameter of the impression made by a ball of given diameter applied under a known load. Values are expressed in Brinell hardness number (BHN).

Brinell hardness number – It is a number related to the applied load and to the surface area of the permanent impression made by a ball indenter computed from an equation.

Brinell hardness test – Brinell hardness is determined by forcing a hard steel or carbide sphere of a specified diameter under a specified load into the surface of a material and measuring the diameter of the indentation left after the test. The Brinell hardness number, or simply the Brinell number, is obtained by dividing the load used, in kg, by the actual surface area of the indentation, in sq mm. The result is a pressure measurement, but the units are normally not stated.

Brinelling – It is the indentation of the surface of a solid body by repeated local impact or impacts, or static overload. Brinelling can occur especially in a rolling-element bearing. It is also damage to a solid bearing surface characterized by one or more plastically formed indentations brought about by overload.

Brine quenching – It is a quenching in which brine (salt water-chlorides, carbonates, and cyanides) is the quenching medium. The salt addition improves the efficiency of water at the vapour phase or hot stage of the quenching process.

Briquette – A briquette is a compressed block of coal dust or other combustible biomass material used for fuel and kindling to start a fire. The term derives from the French word ‘brique’, meaning brick.

Briquetting process – It is a process which is used to recycle and utilize the plant waste by-products of fine particle size. The briquetting process converts the fine particles into cold bonded briquettes. In this process, different waste by-products can be easily agglomerated using very small quantity of the binder. The briquetting process avoids heating up, softening, and melting the fine particles, which can save a lot of fossil energy and decrease the environmental pollution. It is also cost effective than other agglomerating processes because of lesser number of processing steps.

Brittle crack propagation – It is a very sudden propagation of a crack with the absorption of no energy except which stored elastically in the body. Microscopic examination can reveal some deformation even though it is not noticeable to the unaided eye.

Brittle erosion behaviour – It is the erosion behaviour having characteristic properties (e.g., little or no plastic flow, the formation of cracks) which can be associated with brittle fracture of the exposed surface. The maximum volume removal occurs at an angle near 90-degree, in contrast to around 25-degree for ductile erosion behaviour.

Brittle fracture – It consists of separation of a solid accompanied by little or no macroscopic plastic deformation. Typically, brittle fracture occurs by rapid crack propagation with less expenditure of energy than for ductile fracture. Brittle tensile fractures have a bright, granular appearance and show little or no necking. A chevron pattern can be present on the fracture surface, pointing toward the origin of the crack, especially in brittle fractures in flat platelike components. Examples of brittle fracture include trans-granular cracking (cleavage and quasi-cleavage fracture) and inter-granular cracking (decohesive rupture). Majority of the structural steels show a transition in fracture behaviour, that is, from ductile to brittle when the temperature is lowered to some critical temperature which is known as the nil-ductility transition temperature. This temperature is defined as that temperature at which steel loses its ability to flow plastically in the presence of a sharp, crack-like discontinuity. At and below the nil-ductility transition temperature, a brittle cleavage fracture initiates from this discontinuity when stresses approaching the yield strength are reached in the volume of material surrounding the discontinuity. Once initiated, brittle fracture can propagate easily through regions of the structure which are subjected only to low levels of applied stress. In some steels, the transition from ductile to brittle fracture can occur at relatively high temperatures if a mechanical or metallurgical notch is present. If no sharp notch or crack is present, temperatures as low as minus 75 deg C are necessary to produce brittle fracture.

Brittleness – It is the tendency of a material to fracture without first undergoing significant plastic deformation. It describes the property of a material that fractures when subjected to stress but has a little tendency to deform before rupture. A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a sharp snapping sound.

Brittleness point – It is the lowest temperature at which rubber materials do not show brittle failure when impacted under specified conditions.

Brittle nugget – It is a non-standard term used to describe a faying plane failure in a resistance weld peel test.

Broaching – It is cutting with a tool which consists of a bar having a single edge or a series of cutting edges (i.e., teeth) on its surface. The cutting edges of multiple-tooth, or successive single-tooth, broaches increase in size and / or change in shape. The broach cuts in a straight line or axial direction when relative motion is produced in relation to the work-piece, which can also be rotating. The entire cut is made in single or multiple passes over the work-piece to shape the needed surface contour.

Broad goods – It is the fibre which is woven to form fabric up to 1,270 mm wide. It may or may not be impregnated with resin and is normally furnished in rolls of 25 kilograms to 140 kilograms.

Broken matte finish – It is non-uniform surface on the inside of packed rolled foil (bright spots).

Broken views – Broken views in engineering drawings are normally used for parts having one of its dimensions considerably larger than the other dimensions (such as long shafts) in order to make it possible to display the drawing view in a larger scale on a smaller size drawing sheet. In a broken view, portions of the view which do not contain any details are broken out (removed) and the remaining portions of the view are brought closer together.

Bromide – It is a binary compound of bromine with another element or a radical including some (such as potassium bromide). A bromide ion is the negatively charged form (Br⁻) of the element bromine, a member of the halogens group on the periodic table. Most bromides are colourless. Bromides have several practical roles, being found in anticonvulsants, flame-retardant materials, and cell stains.

Bronze – It is a copper-rich copper-tin alloy with or without small proportions of other elements such as zinc and phosphorus. By extension, certain copper-base alloys containing considerably less tin than other alloying elements, such as manganese bronze (copper-zinc plus manganese, tin, and iron) and leaded tin bronze (copper-lead plus tin and sometimes zinc). Also, there are certain other essentially binary copper-base alloys containing no tin, such as aluminum bronze (copper-aluminum), silicon bronze (copper-silicon), and beryllium bronze (copper-beryllium). Also, there are trade designations for certain specific copper-base alloys which are actually brasses, such as architectural bronzes (57 % Cu, 40 % Zn, 3 % Pb) and commercial bronze (90 % Cu, 10 % Zn).

Bronze welding – It is a non-standard term for braze welding.

Bronzing – It is applying a chemical finish to copper or copper-alloy surfaces to alter the color. It is also plating a copper-tin alloy on various materials.

Brownfield expansion – It means adding on to the existing facility. It contrasts to a greenfield plant which means a facility new from the ground up.

Brownian motion – It is the random motion of particles suspended in a medium (a liquid or a gas). This motion pattern typically consists of random fluctuations in a particle’s position inside a fluid sub-domain, followed by a relocation to another sub-domain.

Brown staining reaction – It is the reactions between exposed inter-metallic layers (specifically the iron portion of the layers) and oxygen, resulting in surface colour changes from gray to brown.

Brush or carbon brush– It is a sliding electrical contact between a moving part and a stationary part.

Brush anodizing – It is an anodizing process similar to brush plating.

Brush blasting – Galvanized steel needs to be lightly abrasive blasted prior to painting. Brush blasting needed the use of fine abrasive media at relatively low pressure (less than 2.5 atmospheres) to prevent damage to the galvanized coating.

Brushed direct current electric motor – It is an electric motor with brushes.

Brushless direct current electric motor – It is an electric motor without brushes.

Brush plating – It consists of plating with a concentrated solution or gel held in or fed to an absorbing medium, pad, or brush carrying the anode (usually insoluble). The brush is moved back and forth over the area of the cathode to be plated.

Brush polishing (electrolytic) – It is a method of electropolishing in which the electrolyte is applied with a pad or brush in contact with the part to be polished.

B-stage – It is an intermediate stage in the reaction of certain thermosetting resins in which the material softens when heated and is plastic and fusible but may not entirely dissolve or fuse. It is also called resistol. The resin in an uncured prepreg or premix is normally in this stage.

Bubble leak test – It is a method which is used to identify and locate leaks in packages or containers and it can be used as seal integrity test. It involves immersing the test sample in a liquid, typically water, and then applying a vacuum or pressure differential. Any leaks in the sample allows air or gas to escape, forming visible bubbles in the liquid. This simple visual indication of a leak makes the bubble test leak method an accessible and straight-forward choice for several industries to test packaging quality.

Bubbler method – In bubbler method, a probe is inserted into the measuring medium either from the side or from the bottom and air or an inert gas is injected into the flume and the air bubbles to the top, thus the name bubbler method. For injecting the gas, a purge meter with needle valve and differential pressure regulator is used. After the regulator, which acts as a restriction, a pressure exists in the probe which is the same as the hydrostatic pressure at the end of the tube. The needle valve is used to set the bubble flow rate and the differential pressure regulator to maintain a constant flow rate. A pressure transmitter processes the level proportional pressure.

Bubble structure – It consists of size and spatial distribution of voids within fired porcelain enamel.

Bubble tight shut-off – It describes the sealing capability of a valve. During gas pressure testing of a valve in the closed position, leakage past the seat is collected and bubbled through water. To qualify as ‘bubble tight’, no bubbles are to be observed in a prescribed time span.

Bubbling fluidized-bed reactor – A fluidized bed consists of a bed of particles that is kept fluidized by the continuous upward flow of a gas. Typically, the system consists of a vertical cylindrical vessel with a perforated distributor plate at the bottom. Some material in particulate form (usually sand) is placed inside the vessel, and gas flows from the distributor plate upward. If the velocity of the gas is small, it simply flows around the particles and leave at the top. At this situation, the bed is called a fixed bed. If the gas velocity keeps increasing, at some point the force exerted upwards on each particle equals the particle weight. In that situation, the particle is suspended and the gas velocity is called minimum fluidization velocity. Any additional increase in velocity creates bubbles of gas which rapidly flow upward in the system. This is called a bubbling fluidized bed.

Bubbly oil – It is the oil containing bubbles of gas.

Bucket conveyors – These conveyors convey bulk loads in bucket shaped vessels which are attached to a system of moving chains or belt. These are normally classified as (i) gravity discharge bucket conveyor, (ii) pivoted bucket conveyor and (iii) bucket elevator. Gravity discharge bucket conveyor also called V-bucket conveyor has been described under ‘flight conveyor’ and pivoted bucket conveyor has been described under ‘suspended tray conveyor’.

Bucket elevator conveyor belt – This belt has bolt holes to fix buckets along the entire belt length, making it apt to be torn easily and receiving pulled force with the weight of the bucket. It also has a withdrawal force different from that of the ordinary belts in bending in connection with pulleys. Hence, its carcass mainly uses polyester fabric which can address to such problems. Steel cord is used when a highly powerful belt is needed. Fig 6 gives the structure of bucket elevator conveyor belt.

Bucket elevators – They are used for conveying bulk materials from a lower level to a higher level. They are powered equipment for conveying bulk materials in a vertical or steep inclined path, consisting of an endless belt, or chain / chains to which metallic buckets are fixed. With the flexible belt / chain, the buckets move uni-directionally within a casing and collect bulk materials at bottom end of the equipment and deliver it at the top end. A typical bucket elevator has the major parts consisting of (i) an endless pulling member (flat belt or chain), (ii) driving and take up pulleys or sprockets at top and bottom respectively, mounted on bearings and blocks, (iii) metal casing covering the entire elevator and consisting of head at the top, boot at the bottom and intermediate sections, all joined at flanges by fasteners, (iv) buckets, normally made out of sheet metal, which are attached at definite pitch to the pulling member by fasteners (screw and nuts, riveted etc.), (v) drive at the top consisting of an electric motor, gearbox, and couplings, (vi) hold back brake attached to the top pulley / sprocket shaft, to prevent reverse motion of the elevator when drive is stopped, (vii) feed hopper attached to the boot for feeding materials to the elevator, (viii) delivery / discharge spout fixed with the top part of the casing, through which the material is discharged, (ix) manholes provided in the casing to check operations of the elevator, and (x) guides and guide sprockets provided for belt and chain respectively to keep them in a straight path.

Buckle – It is bulging of a large, flat face of a casting. In investment casting, it is caused by dip coat peeling from the pattern. It is an indentation in a casting, resulting from expansion of the sand, and can be termed the start of an expansion defect. It is also a local waviness in metal bar or sheet, normally transverse to the direction of rolling.

Buckle, arbor – It is the bend, crease, wrinkle, or departure from flat, occurring perpendicular to the slit edge of a coil and which are repetitive in nature, with severity decreasing as the distance increases in the coil from the original source. Normally, it is found on the inside diameter of a coil but can appear on the coil outside diameter as a result of a prior winding operation.

Buckle, centre – It is the undulation (wavy region) in the centre of the metal.

Buckle, edge – It is undulation (wavy region) along the edge(s) of the metal.

Buckle, quarter – It is undulation (wavy region) which occurs approximately at both quarter points across the width.

Buckle, trapped – It is undulation (wavy region) which  is smaller in size and frequently circular in shape.

Buckling – It is a mode of failure normally characterized by an unstable lateral material deflection because of the compressive action on the structural element involved. In metal forming, it is a bulge, bend, kink, or other wavy condition of the work-piece caused by compressive stresses.    

Buckstay – It is a structural member placed against a furnace or boiler wall to restrain the motion of the wall.

Budget – It is the sum of money allocated for an activity. The term also refers to a comprehensive list of revenues and expenses.

Buffer – It is a substance which by its addition or presence tends to minimize the physical and chemical effects of one or more of the substances in a mixture. Properties frequently buffered include pH, oxidation potential, and flame or plasma temperatures. It is also a substance whose purpose is to maintain a constant hydrogen-ion concentration in water solution, even when acids or alkalis are added. Each buffer has a characteristic limited range of pH over which it is effective.

Buffer gas – In powder metallurgy, it is a protective gas curtain at the charge or discharge end of a continuously operating sintering furnace.

Buffing – It consists of developing a lustrous surface by contacting the work with a rotating buffing wheel.

Buff sections – These are fabric, paper, or leather disks with concentric centre holes held together by different types of sewing to provide degrees of flexibility or hardness. These sections are assembled to make wheels for polishing or buffing.

Buffing wheel – It consists of buff sections assembled to the required face width for use on a rotating shaft between flanges. It is sometimes called a buff.

Bulging – Bulging of continuously cast steel products between supporting rolls is caused by internal ferrostatic pressure acting on the solidifying strand shell because of the weight of liquid steel and the height from the meniscus. Bulging is directly responsible for internal cracks, centre-line segregation, and permanent deformation, which lead to poor quality of the continuously cast products. The bulging of slabs can also cause an increase of the load transmitted to the rolls and enhance their rate of wear.

Build-up – It is a weld surfacing variation in which surfacing metal is deposited for achieving the needed dimensions. It is also excessive electro-deposition which occurs on high-current density areas, such as corners or edges.

Building engineering – It is a discipline which deals with the engineering and construction of buildings, such as environmental, structural, mechanical, electrical, computational, embeddable, and other research domains.

Building height – Building height is the eave height which normally is the distance from the bottom of the main frame column base plate to the top outer point of the eave strut. Eave height is the distance from the finished floor to the top outer point of the eave strut. There is to be a safety distance between the top edge of the crane runway rail and the first obstacle edge in the building (e.g. roof beams, lights, and pipes).

Building up – It consists of electroplating for the purpose of increasing the dimensions of a work-piece.

Built-up edge – It consists of chip material adhering to the tool face adjacent to the cutting-edge during cutting. It is also material from the work-piece, especially in machining, which is stationary with respect to the tool.

Bulging – It consists of expanding the walls of a cup, shell, or tube with an internally expanded segmented punch or a punch composed of air, liquids, or semi-liquids such as waxes, rubber, and other elastomers. It is also the process of increasing the diameter of a cylindrical shell (normally to a spherical shape) or of expanding the outer walls of any shell or box shape whose walls were previously straight.

Bulk ceramic fibres – These fibres are loose, long and flexible with high refractory properties, and are produced by the ‘blown’ and ‘spun’ processes.

Bulk density – It describes the measure of mass and volume including the pore space. Bulk density is normally considered in conjunction with apparent porosity. It is a measure of the weight of a given volume of the material.

Bulk factor – It is the ratio of the volume of a raw moulding compound or powdered plastic to the volume of the finished solid piece produced therefrom. It is the ratio of the density of the solid plastic object to the apparent or bulk density of the loose moulding powder.

Bulk ferroalloys – These are high carbon ferro-manganese, medium carbon ferro-manganese, low carbon ferro-manganese, silico-manganese, medium carbon silico-manganese, ferro-silicon, high carbon ferro chrome, charge-chrome, medium carbon ferro-chrome, and low carbon-ferrochrome. Bulk ferroalloys are produced in large quantities in electric arc furnaces. They are used in steel making and steel or iron foundries exclusively.

Bulk formality – It is also known as workability. It refers to the relative ease with which a metal can be shaped through deformation processes such as forging, extrusion, or rolling. Bulk formability is related to sheet formability in only the broadest sense, in that both characteristics provide quantitative estimates of the strength and ductility of a metal. The latter property, ductility, or the resistance of the material to failure, is normally of primary concern in describing both bulk and sheet formability.

Bulk forming processes – Bulk forming processes such as forging, extrusion, drawing, and rolling are key processes of modern industrial manufacturing. In these processes, the input material is billet, rod, or slab form and a considerable increase in surface-to-volume ratio in the formed part occurs under the action of largely compressive loading. Bulk forming processes ae especially for structural components and safety-critical applications. Formed components are essential because of their reliable mechanical properties.  Even though these forming processes are industrial standard, high-quality parts can only be produced with thorough material and process know-how

Bulk materials – Bulk materials are those dry materials which are powdery, granular or lumpy in nature, and are stored in heaps. Examples of bulk materials are minerals, ores, coal, cereals, woodchips, sand, gravel, clay, cement, ash, salt, chemicals, grain, sugar, flour and stone in loose bulk form.

Bulk modulus – It is the ratio of the hydrostatic pressure to the volume strain. It actually determines how much a material compresses under a given quantity of external pressure. It is expressed in stress units, e.g., gigapascal (GPa). A representative value of the bulk modulus for steel is 160 GPa and for water is 2.2 GPa.

Bulk modulus of elasticity – It is the measure of resistance to change in volume. It is the ratio of hydrostatic stress to the corresponding unit change in volume. It is also known as bulk modulus, compression modulus, hydrostatic modulus, and volumetric modulus of elasticity.

Bulk moulding compound (BMC) – It is a thermosetting resin which is mixed with strand reinforcement, fillers, and so on, into a viscous compound for compression or injection moulding.

Bulk sample – It is a large sample of mineralized rock, frequently hundreds of tons, selected in such a manner as to be representative of the potential ore-body being sampled. It is used to determine metallurgical characteristics.

Bulk volume – It is the volume of the powder fill in a die cavity. In refractories, bulk volume is the sum of the volumes of the solid materials, the open pores and the closed pores in a porous refractory.

Bull block – It is a machine with a power-driven revolving drum for cold drawing wire through a drawing die as the wire winds around the drum.

Bulldozer – A bulldozer or dozer (also called a crawler) is a large, motorized machine equipped with a metal blade to the front for pushing material such as soil, sand, snow, rubble, or rock during construction work. Bulldozer is also a slow-acting horizontal mechanical press with a large bed used for bending and straightening. The work is done between dies and can be performed hot or cold. The machine is closely allied to a forging machine.

Bullion – It is a semi-refined alloy containing sufficient precious metal to make recovery profitable. It is also refined gold or silver, uncoined.

Bull’s-eye structure – It is the micro-structure of malleable or ductile cast iron when graphite nodules are surrounded by a ferrite layer in a pearlitic matrix.

Bumper – It is a machine used for packing moulding sand in a flask by repeated jarring or jolting.

Bumper (buffer) – It is an energy absorbing device for reducing impact when a moving crane or trolley reaches the end of its permitted travel, or when two moving cranes or trolleys come into contact. This device can be attached to the bridge, trolley, or runway stop.

Bumping – It is forming a dish in metal by means of many repeated blows. It is also forming a head. It is also setting the seams on sheet metal parts. It is ramming sand in a flask by repeated jarring and jolting.

Bundle – It is a general term for a collection of essentially parallel filaments or fibres.

Bunkers – Bunkers are essentially large bins used for storage of materials. They are normally made of concrete. These can be a few hundred meters in length. Belt conveyors with automatic trippers and dumpers etc. are used for filling of the bunkers. Discharge of the materials from the bunkers at the desired rate is carried out by using different types of feeders.

Bunsen burner – It is a kind of ambient air gas burner used as laboratory equipment. It produces a single open gas flame, and is used for heating, sterilization, and combustion. The gas can be natural gas (which is mainly methane) or a liquefied petroleum gas, such as propane, butane, or a mixture. Combustion temperature achieved depends in part on the adiabatic flame temperature of the chosen fuel mixture.

Buoyancy – It is a net upward force exerted by a fluid which opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus, the pressure at the bottom of a column of fluid is higher than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is higher than at the top of the object. The pressure difference results in a net upward force on the object. The magnitude of the force is proportional to the pressure difference, and is equivalent to the weight of the fluid which otherwise occupies the submerged volume of the object, i.e. the displaced fluid.

Burden – Burden is the furnace charge, of iron-bearing materials (e.g. iron ore pellets, and sinter), coke, and flux (e.g. limestone) descends through the shaft, where it is preheated and reacts with ascending reducing gases to produce liquid iron and slag.

Burden distribution – It indicates the distribution of the burden materials across the blast furnace cross-section during their charging in the BF. Control of the burden distribution is important for improving the gas utilization and lowering of the fuel rate. Control of the burden distribution is also necessary to control the shape of the cohesive zone of the blast furnace.

Burden materials – Burden materials are (i) fuels and reductants like blast furnace coke, and nut coke, (ii) iron bearing raw materials like sinter, pellet, and calibrated lump ore also known as sized iron ore, (iii) fluxing materials like lime stone, dolomite, and quartzite, and (iv) additives like manganese ore, quartzite, and titani-ferrous iron ore etc.

Burette – It is an instrument used to deliver variable and accurately known volumes of a liquid during titration or volumetric analysis. Burettes are normally made from uniform-bore glass tubing in capacities of 5 milliliters to 100 milliliters, the most common being 50 milliliters.

Burn – It means the heat treatment to which refractory materials are subjected in the firing process.

Burn down chart – It is a graph which shows the relationship between the number of tasks to be completed and the quantity of time left to complete these tasks.

Burned – It is showing evidence of thermal decomposition or charring through some discolouration, distortion, destruction, or conversion of the surface of the plastic, sometimes to a carbonaceous char.

Burned deposit – It is a dull, nodular electro-deposit resulting from excessive plating current density.

Burned-in sand – It is a defect consisting of a mixture of sand and metal cohering to the surface of a casting.

Burned-on sand – It is a misnomer normally indicating metal penetration into sand resulting in a mixture of sand and metal adhering to the surface of a casting.

Burned sand – It is the sand in which the binder or bond has been removed or impaired by contact with molten metal.

Burner – It is the device used to burn the fuel, with an oxidizer to convert the chemical energy in the fuel into thermal energy. Burner introduces fuel and air into a furnace at the desired velocities, turbulence, and concentration. A given combustion system can have a single burner or several burners, depending on the size and type of the application. Burners’ heat (thermal energy) is derived by burning fuel and is required for technological processes. Burners are essential components of a furnace. They describe a series of equipment for burning various types of fuel under suitable conditions for perfect combustion. Burner operates by sucking in the fuel and the combustion support air (oxidizer), mixes them thoroughly together and safely ignites them inside the furnace.

Burner block – It contains a cavity extending through the block, and fuel and oxidant normally are supplied at one end of this cavity while products of combustion pass out at the other end. The shape of the cavity frequently is important in controlling the efficiency of combustion. Burner blocks are normally made of castable refractories. For burner blocks normally castings are made, and then they are dried and fired.

Burner wind-box – It is a plenum chamber around a burner which maintains an air pressure sufficient for proper distribution and discharge of secondary air.

Burner wind-box pressure – It is the air pressure maintained in the wind-box or plenum chamber measured above atmospheric pressure.

Burning – It is permanently damaging a metal or alloy by heating to cause either incipient melting or intergranular oxidation. During subcritical annealing, particularly in continuous annealing, it is production of a severely decarburized and grain-coarsened surface layer which results from excessively prolonged heating to an excessively high temperature. In grinding, it is getting the work hot enough to cause discolouration or to change the micro-structure by tempering or hardening. In sliding contacts, it is the oxidation of a surface because of the local heating in an oxidizing environment. It is also a non-standard term for oxygen cutting. In refractories, it is the final heat treatment in a kiln to which refractory brick and shapes are subjected in the process of manufacture for the purpose of developing bond and other necessary physical and chemical properties.

Burnish – It is to alter the original manufactured surface of a sliding or rolling surface to a more polished Condition. It is also to apply a substance to a surface by rubbing.

Burnishing – It consists of finish sizing and smooth finishing of surfaces (previously machined or ground) by displacement, rather than removal, of minute surface irregularities with smooth-point or line-contact fixed or rotating tools. It is developing a smooth finish on a metal by tumbling or rubbing with a polished hand tool.

Burn off – It is the unintentional removal of an auto-catalytic deposit from a non-conducting substrate, during subsequent electroplating operations, owing to the application of excessive current or a poor contact area. In porcelain enamel, it is a condition caused by thin application resulting in a black or yellow-green colour. The enamel layer can appear transparent. Lack of bubble structure and shinier scale can be associated with this condition.

Burnt deposit – It is a rough, non-coherent or otherwise unsatisfactory deposit produced by the application of an excessive current density and normally containing oxides or other inclusions.

Burn through – It is a non-standard term for excessive melt through or a hole. In sintering of ores, burn-through is where the sinter layer has completely burned through its section and is detected by temperature probes under the sinter bed. Burn through is to be achieved but is not to occur too soon after the ignition hood. The draught on the strand is maintained at a preset value by controlling the main fan louvers from pressure measurements in the wind main. This governs the point at which burn through occurs.

Burn through point – Air is sucked from the bottom of the bed of mixed material throughout the sintering machine. Fire penetrates the mixed material gradually, until it reaches the hearth layer. This end point of burning is called burn through point.

Burn through weld – It is a non-standard term for a seam weld or spot weld.

Burn-up – It is a measure of thermal energy released by nuclear fuel relative to its mass, typically Gigawatt days per ton of fuel (GWd/t).

Burr – It is a thin ridge or roughness left on a work-piece (e.g., forgings or sheet metal blanks) resulting from cutting, punching, or grinding. It is also a rotary tool having teeth similar to those on hand files.

Burr hardness – It is the hardness of the burr in the vicinity of the base of the burr.

Burr height – It is the distance a burr projects above the surface of the work-piece.

Burring – It is the process of removing burrs (preferred word is deburring). It is also the intentional production of a small flange around holes in a press-working operation (preferred word is flanging). It is also the act of burr formation.

Burst point – It is a point in a network diagram at which multiple successor activities originate from a common predecessor activity. None of the successor activities can start until one finishes the predecessor activity.

Burst pressure – It is that pressure at which rupture of a stressed element or pressure-containing vessel takes place.

Burst strength or bursting strength – It is a measure of the ability of a material to withstand internal hydrostatic or gas dynamic pressure without rupture. It is the hydraulic pressure need to burst a vessel of given thickness. It is the pressure needed to rupture a foil sample when it is tested in a mullen instrument under specified conditions.

Bus – It is a rigid conducting section, for carrying current to the anode and cathode bars.

Bus bar – It is an electrical fitting which is used to connect external conductors to the interior of apparatus.

Bush bearing – It is a plain bearing in which the lining is closely fitted into the housing in the form of a bush, normally surfaced with a bearing alloy.

Busheling – It is a high-quality grade of scrap steel with no rust, paint, or non-metallic contaminants. It is often sourced from manufacturing plants, metal fabrication shops, and industrial practices. It can consist of new production scrap metal, such as stampings, trimmings, and cuttings, and is very frequently composed of steel and iron.

Bushing – It is a normally removable cylindrical lining in an opening of a mechanical part to limit the size of the opening, resist wear, or serve as a guide.

Bushings – These are special type of pipe fittings normally make to use the diameter of a pipe fitting smaller. They differ from reducers in that they make abrupt changes in diameter and take very little space. Two examples of galvanized steel bushings are face bushings, which take the least amount of space, and hex bushings which can be tightened with an adjustable wrench.

Business process re-engineering (BPR) – It is a strategy of the management of an organization which focuses on the analysis and design of different business processes and flow of work within the organization. It seeks to help the organization radically to restructure its operations by focusing on the ground up design of the business processes. Business process re-engineering helps the organization to rethink in fundamental way how it is should do the work in order to drastically reduce operational costs, improve service to its customers, and become a world class organization.  It is also sometimes known as business process redesign, business transformation, or business process change management.

Buster – It is a pair of shaped dies used to combine preliminary forging operations, such as edging and blocking, or to loosen scale.

Bustle pipe – It is also known as bustle main and is a large diameter refractory lined pipe encircling the blast furnace shell above the tuyere level. Through the bustle main hot blast air is supplied to the BF through the tuyere stock.

Butler finish – It is a semi-lustrous metal finish composed of fine, uniformly distributed parallel lines, normally produced with a soft abrasive buffing wheel. It is similar in appearance to the traditional hand-rubbed finish on silver.

Butt curl – It occurs in the semi-direct chill casting of aluminum slabs. It can cause metal bleeding and hot cracking accompanied by coincident bowing which leads to poor yields in slab preparation.

Butterfly valves – Butterfly valves consist of a disc attached to a shaft with bearings used to facilitate rotation. The characteristics of the flow can be controlled by changing the design of the disk being used. For example, there are designs which can be used in order to reduce the noise caused by a fluid as it flows through. Butterfly valves are good for situations with straight flow and where a small pressure drop is needed. There are also high-performance butterfly valves. They have the added benefit of reduced torque issues, tight shutoff, and very good throttling.

Buttering – It is a form of surfacing in which one or more layers of weld metal are deposited on the groove face of one member (for example, a high-alloy weld deposit on steel base metal which is to be welded to a dissimilar base metal). The buttering provides a suitable transition weld deposit for subsequent completion of the butt weld (joint).

Butt joint – It is a joint between two members aligned approximately in the same plane. It is a type of edge joint in which the edge faces of the two adherends are at right angles to the other faces of the adherends.

Butt of pile – This term is normally used in conjunction with the timber piles. It is the upper or larger end of the pile, i.e., the end closest to the hammer.

Button – It is a globule of metal remaining in an assaying crucible or cupel after fusion has been completed. It is also that part of a weld which tears out in destructive testing of a spot, seam, or projection welded sample.

Butt-weld ends – It is the end connection of a valve suitably prepared for butt-welding to a connecting piping.

Butt welding – Butt welding is when two pieces of metal are placed end-to-end without overlap and then welded along the joint. Importantly, in a butt joint, the surfaces of the work-pieces being joined are on the same plane and the weld metal remains within the planes of the surfaces.

Butt-weld pipe – It is the standard pipe used in used in several applications. For its production, heated skelp is passed continuously through welding rolls, which forms the tube and squeeze the hot edges together to make a solid weld.

Butyl rubber – Butyl rubber is a polymerization product of isobutylene and isoprene (IIR). It has a very good ozone and temperature resistance. It has a very good resistance to ageing. It is able to withstand temperatures of – 30 deg C to + 150 deg C. It has limited resistance to acids and alkalis. It is mainly used for heat resistant conveyor belting.

Buzzer or beeper – It is an audio signaling device, which can be mechanical, electro-mechanical, or piezoelectric. The device produces a sound when energized.

By-pass – It is a passage for a fluid, permitting a portion of the fluid to flow around its normal pass flow channel.

By-product – It is a secondary product recovered in a process.

By-product coke ovens – These are the chambers made of refractories to convert coal into coke by carbonizing coal in absence of air and there by distilling the volatile matter out of coal. Byproduct coke ovens are arranged in a battery containing number of coke ovens (can vary from 20 to 100 in each battery).