Glossary of technical terms for the use of metallurgical engineers Terms starting with alphabet ‘I’
Glossary of technical terms for the use of metallurgical engineers
Terms starting with alphabet ‘I’
IACS – It means ‘International annealed copper standard’ which is a standard reference used in reporting electrical conductivity. The conductivity of a material, in % IACS, is equal to 1724.1 divided by the electrical resistivity of the material in nsigma·m.
I-beam – It is a structural steel shape with ‘I’ cross-section. I-beams are typically made of structural steel and serve a wide variety of construction uses. The horizontal elements of the I-beam are called flanges, and the vertical element is known as the ‘web’. The web resists shear forces, while the flanges resist most of the bending moment experienced by the beam. The Euler–Bernoulli beam equation shows that the I-shaped section is a very efficient form for carrying both bending and shear loads in the plane of the web. On the other hand, the cross-section has a reduced capacity in the transverse direction, and is also inefficient in carrying torsion, for which hollow structural sections are frequently preferred.
Ice point – It is the temperature at which liquid and solid water are in equilibrium under atmospheric pressure. The ice point is by far the most important ‘fixed point’ for defining temperature scales and for calibrating thermometers. It is 0-degre C or 273.15 K.
Ideal crack – It is a simplified model of a crack which is used in elastic-stress analysis. In a stress-free body, the crack has two smooth surfaces which are coincident and join within the body along a smooth curve called the crack front. In two-dimensional representations, the crack front is called the crack tip.
Ideal-crack-tip stress field – It is the singular stress field, which is infinitesimally close to the crack front, that results from the dominant influence of an ideal crack in an elastic body which is deformed. In a linear-elastic homogeneous body, the significant stress components vary inversely as the square root of the distance from the crack tip. In a linear-elastic body, the crack-tip stress field can be regarded as the superposition of three component stress fields called modes.
Ideal critical diameter (DI) – Under an ideal quench condition, the bar diameter which has 50 % martensite at the centre of the bar when the surface is cooled at an infinitely rapid rate (i.e., when H = infinity, where ‘H’ is the quench severity factor or Grossmann number).
Ideal gas – It is a theoretical gas composed of several randomly moving point particles which are not subject to interparticle interactions. The ideal gas concept is useful since it obeys the ideal gas law, a simplified equation of state, and is amenable to analysis under statistical mechanics. The requirement of zero interaction frequently can be relaxed if, e.g., the interaction is perfectly elastic or regarded as point-like collisions. Under different conditions of temperature and pressure, several real gases behave qualitatively like an ideal gas where the gas molecules (or atoms for monatomic gas) play the role of the ideal particles. Several gases such as nitrogen, oxygen, hydrogen, noble gases, some heavier gases like carbon di-oxide and mixtures such as air, can be treated as ideal gases within reasonable tolerances over a considerable parameter range around standard temperature and pressure. Normally, a gas behaves more like an ideal gas at higher temperature and lower pressure, since the potential energy because of the inter-molecular forces becomes less significant compared with the kinetic energy of the particles, and the size of the molecules becomes less significant compared to the empty space between them. One mole of an ideal gas has a volume of 22.71095464… litres at standard temperature and pressure (a temperature of 273.15 K and an absolute pressure of exactly 0.1 MPa).
Ideal gas constant (R) – It is the molar equivalent to the Boltzmann constant, expressed in units of energy per temperature increment per quantity of substance, rather than energy per temperature increment per particle. The constant is also a combination of the constants from Boyle’s law, Charles’s law, Avogadro’s law, and Gay-Lussac’s law.
Ideal gas law – It is the equation of state of a hypothetical ideal gas. It is a good approximation of the behaviour of several gases under several conditions, although it has several limitations. The ideal gas law is frequently written in an empirical form PV = nRT, pV=nRTwhere ‘pP’, ‘V’, Vand ‘T’T are the pressure, volume, and temperature respectively, ‘n’n is the quantity of substance, and ‘R’R is the ideal gas constant.
Ideal machine – It refers to a hypothetical mechanical system in which energy and power are not lost or dissipated through friction, deformation, wear, or other inefficiencies. Ideal machines have the theoretical maximum performance, and hence are used as a baseline for evaluating the performance of real machine systems. A simple machine, such as a lever, pulley, or gear train, is ‘ideal’ if the power input is equal to the power output of the device, which means there are no losses. In this case, the mechanical efficiency is 100 %.
Ideal mechanical advantage (IMA) -It is the mechanical advantage of a device with the assumption that its components do not flex, there is no friction, and there is no wear. It is calculated using the physical dimensions of the device and defines the maximum performance the device can achieve.
Identification – It is the marking / labeling of steel so that different customer products can be distinguished from one another after the product manufacture.
Identification cross reference drawing – It is an administrative type drawing which assigns unique identifiers which are compatible with automated data processing systems, item identification specifications, and provides a cross reference to the original incompatible identifier. It does not specify any engineering or design requirements beyond those already contained in the drawings, and specification etc. governing the original item.
Identification product code – It is a unique identifier, assigned to each finished / manufactured product which is ready, to be marketed or for sale. A bar code is a type of the identification product code. Identification tag (label) – It is for identifying quality/ dimension of the product as well as distinguishing between prime and defective products. Identification tags (labels) can be embedded into almost any material – textile, paper, plastic, etc. They can be directly incorporated into goods, their labels, or in the coatings during the manufacturing process.
Identified project – An identified project is a project associated with a known source.
Identified resource – It is the Resource whose location, grade, quality, and quantity are known or estimated from specific geological evidence. Identified resources include economic, marginally economic, and sub-economic components. To reflect varying degrees of geological certainty, these economic divisions can be sub-divided into measured, indicated, and inferred.
Idiomorphic crystal – It is an individual crystal which has grown without restraint so that the habit planes are clearly developed.
Idlers, belt conveyor – Idlers of belt conveyor are the rollers which are used at certain spacing for supporting the active as well as return side of the conveyor belt. Accurately made, rigidly installed and well-maintained idlers are very important for smooth and efficient running of a belt conveyor. Important requirements for idlers are proper support and protection for the belt and proper support for the load being conveyed. They 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. Roll diameter, bearing design, and seal requirements constitute the major components affecting frictional resistance. Selection of the proper roll diameter and size of bearing and shaft is based on the type of service, load carried, belt speed and operating condition.
Idler spacing – It is the distance between two idlers. Factors to be considered when selecting idler spacing are belt weight, material weight, idler load rating, belt sag, idler life, belt rating, belt tension, and radius in vertical curves. More complex issues (such as belt flap or vibration stability in wind, and power usage from belt indentation, material tramping, and rolling resistance) are affected less by idler spacing.
Igneous iron ores -These iron ore deposits are formed by crystallization from liquid rock materials, either as layered type deposits that possibly are the result of crystals of heavy iron bearing minerals settling as they crystallize to form iron rich concentrations, or as deposits which show intrusive relationship with their wall rocks. These ore deposits are either tabular or irregular and are composed largely of magnetite with varying quantities of hematite. Igneous ores are normally high in iron content and are often high in phosphorus or titanium content.
Igneous rocks – These are the rocks formed by the solidification of molten material from far below the earth’s surface.
Ignition furnace, ignition hood – It is the furnace, where raw mix is ignited by burner flame, Burner uses a mixture of coke oven gas, blast furnace gas and sometimes natural gas as the fuel. The calorific value of the mixture and the set hood temperature are controlled. A separate control system is provided to maintain a fixed hood pressure by adjusting the wind-box dampers immediately under the ignition hood.
Ignition loss – It is the difference in weight before and after burning. As with glass, it is the burning off of the binder or size.
Ignition temperature – It is the lowest temperature of a fuel at which combustion becomes self-sustaining.
Ilmenite – It is an ore mineral of titanium, being an iron-titanium oxide.
Illuminants – It is the light oil or coal compounds which readily burn with a luminous flame, such as ethylene, propylene, and benzene.
Illumination – It is the intensity of light falling at a given place on a lighted surface i.e., the luminous flux incident per unit area, expressed in lumens per unit of area. Different types of illumination which are used in metallographical analysis are bright-field illumination, dark-field illumination, differential interference contrast illumination, and polarized light illumination.
Image – It is a representation of an object produced by radiation, normally with a lens or mirror system.
Image analysis – This is enhancement to metallographical microscope observation (MMO) which improves on eye evaluation by using high-speed computer evaluation of video-scanned microscope images to distinguish dark and light regions based on a gray scale cutoff. This method can easily evaluate larger areas and greater inclusion numbers than metallographical microscope observation, but is subject to errors such as mistaking scratches, pitting, and stains for non-metallic inclusions.
Image contrast – It is a measure of the degree of detectable difference in intensity within an image.
Image impedance – It is a parameter which is used in design of electrical networks such as filters.
Image noise reduction – It is a technique which is used to reduce interfering effects in processing of an image.
Image processing – It is the electronic recording, storage, alteration and reproduction of pictures.
Image quality indicator (IQI) – It is one of the methods of controlling the quality of a radiograph. It is also referred to as penetrameters. It provides a means of visually informing the film interpreter of the contrast sensitivity and definition of the radiograph. The image quality indicator indicates that a specified quantity of change in material thickness is detectable in the radiograph, and that the radiograph has a certain level of definition so that the density changes are not lost because of the unsharpness. Without such a reference point, consistency and quality cannot be maintained and defects can go undetected.
Image rotation – In electron optics, it is the angular shift of the electron image of an object around the optic axis induced by the tangential component of force exerted on the electrons perpendicular to the direction of motion in the field of a magnetic lens.
Immersed-electrode furnace – It is a furnace which is used for liquid carburizing of parts by heating molten salt baths with the use of electrodes immersed in the liquid.
Immersion cleaning – It is the cleaning in which the work is immersed in a liquid solution.
Immersion coating – It is a coating produced in a solution by chemical or electro-chemical action without the use of external current.
Immersion etching – It is the method in which a micro-section is dipped face up into etching solution and is moved around during etching. This is the most common etching method.
immersion lens, immersion objective – It is an objective in which a medium of high refractive index is used in the object space to increase the numerical aperture and hence the resolving power of the lens.
Immersion objective (electron optics) – It is a lens system in which the object space is at a potential or in a medium of index of refraction different from that of the image space.
Immersion plate – It is a metallic deposit produced by a displacement reaction in which one metal displaces another from solution, for example: Fe + Cu2+ = Cu + Fe2+.
Immersion plating – It means depositing of a metallic coating on a metal immersed in a liquid solution, without the aid of an external electric current. It is also called dip plating.
Immunity – It is a state of resistance to corrosion or anodic dissolution of a metal caused by thermo-dynamic stability of the metal.
Impact – In crushing terminology, impact refers to the sharp, instantaneous collision of one moving object against another. Both objects can be moving, or one object can be motionless. There are two variations of impact, namely (i) gravity impact, and (ii) dynamic impact. Material dropped onto a hard surface such as a steel plate is an example of gravity impact. Gravity impact is most often used when it is necessary to separate two materials which have relatively different friability. The more friable material is broken, while the less friable material remains unbroken. Separation can then be done by screening. Material dropping in front of a moving hammer (both objects in motion), illustrates dynamic impact. When crushed by gravity impact, the free-falling material is momentarily stopped by the stationary object. But when crushed by dynamic impact, the material is unsupported and the force of impact accelerates movement of the reduced particles toward breaker blocks and/or other hammers. Dynamic impact has definite advantages for the reduction of several materials.
Impact crusher – Impact crushers make use of impact rather than compression to crush material. The material is contained within a cage, with openings of the desired size at the bottom, end, or side to allow crushed material to escape. There are two types of impact crushers namely (i) horizontal shaft impact crusher, and (ii) vertical shaft impact crusher. Impact crushers are frequently used with materials, which are soft or which are easily cleaving from the surface. The crusher consists of a fast-spinning rotor and beaters attached to the rotor. Feed is entering to the crusher from the top and crushing starts immediately when the feed is impacted with beaters towards the crusher’s inner surface. Impact crusher can also be equipped with a bottom screen, which prevents material leaving the crusher until it is fine enough to pass through the screen. This type of crusher is normally used for soft and non-abrasive materials.
Impact energy – It is the quantity of energy, normally given in joules, needed to fracture a material. It is normally measured by means of an Izod test or Charpy test. The type of the sample and test conditions affect the values and hence are to be specified.
Impact extrusion – It is the process (or resultant product) in which a punch strikes a slug (normally unheated) in a confining die. The metal flow can be either between punch and die or through another opening. The impact extrusion of unheated slugs is frequently called cold extrusion.
Impaction ratio – It is the cross-sectional area of undisturbed fluid containing particles which ultimately impinges on a given solid surface, divided by the projected area of the solid surface.
Impact / cut resistant conveyor belt – This type of belt minimizes damages to belt carcass from sharp objects or strong impact, and prevents belts from being cut or broken by damage.
Impact line – It is a blemish on a drawn metal part caused by a slight change in metal thickness. The mark is called an impact line when it results from the impact of the punch on the blank. It is called a recoil line when it results from transfer of the blank from the die to the punch during forming, or from a reaction to the blank being pulled sharply through the draw ring.
Impact load – It is especially severe shock load such as that caused by instantaneous arrest of a falling mass, by shock meeting of two parts (e.g., in a mechanical hammer), or by explosive impact, in which there can be an exceptionally rapid buildup of stress.
Impact pads – These pads, which range from simple rectangular plates to complex shapes with lips for reducing the energy of the impact stream, are inserted on the tundish bottom immediately below the ladle shroud region. Impact pads have been developed to cushion the tundish bottom from the ladle stream impact. Without such a pad, the impact energy can eventually work through the spray lining and result in steel penetration into the back-up shapes. Like dams, weirs and baffles, these high-alumina refractory plates are installed on the back-up lining and are anchored using the spray lining. Within the recent past, large quantity of work has been done to turn the simple impact pad into a turbulence-inhibiting device and a true flow modifying device. The working principle of these high-tech impact pads is to revert the impact stream onto itself, hence using own energy of the stream for dampening it.
Impact resistance – It is the ability to avoid damage because of the contact with a forceful motion or object. Galvanized coating’s uppermost, pure zinc Eta layer is relatively soft and absorbs impact shock, protecting the underlying alloy layers.
Impact sintering – It is an instantaneous sintering process during high energy rate compacting which causes localized heating, welding, or fusion at the particle contacts.
Impact strength – It is a measure of the resiliency or toughness of a solid. The maximum force or energy of a blow (given by a fixed procedure) which can be withstood without fracture, as opposed to fracture strength under a steady applied force.
Impact test – It is a test for determining the energy absorbed in fracturing a test piece at high velocity, as distinct from static test. The test can be carried out in tension, bending, or torsion, and the test bar can be notched or unnotched. Several types of impact tests have been used to evaluate the notch toughness of metals, plastics, and ceramics. The types of impact tests can be normally classified in terms of loading method (pendulum stroke or drop weight loading) and the type of notched sample (e.g., Charpy V-notch, Charpy U-notch, or Izod).
Impact transition temperature – It is the temperature in which the material changes its behaviour from ductile to a brittle. It is also known as the brittle to ductile transition temperature.
Impact tube – It is also known as Pitot tube. It is an instrument which measures the stagnation pressure of a flowing fluid, consisting of an open tube pointing into the fluid and connected to a pressure-indicating device.
Impact velocity – It is the relative velocity between the surface of a solid body and an impacting liquid or solid particle. For describing this velocity completely, it is necessary to specify the direction of motion of the particle relative to the solid surface in addition to the magnitude of the velocity. The related terms which are also in use are (i) absolute impact velocity which is the magnitude of the impact velocity, and (ii) normal impact velocity which is the component of the impact velocity that is perpendicular to the surface of the test solid at the point of impact.
Impact wear – It is the wear of a solid surface resulting from repeated collisions between that surface and another solid body. The term erosion is preferred in the case of multiple impacts and when the impacting body or bodies are very small relative to the surface being impacted.
Impedance – It is the opposition to alternating current presented by the combined effect of resistance and reactance in a circuit. Quantitatively, the impedance of a two-terminal circuit element is the ratio of the complex representation of the sinusoidal voltage between its terminals, to the complex representation of the current flowing through it. In general, it depends upon the frequency of the sinusoidal voltage. Impedance extends the concept of resistance to alternating current circuits, and possesses both magnitude and phase, unlike resistance, which has only magnitude.
Impeller or impellor – It, is a driven rotor which is used to increase the pressure and flow of a fluid. It is the opposite of a turbine, which extracts energy from, and reduces the pressure of, a flowing fluid.
Imperfection – It is a deviation from ideality. An imperfection may or may not be a defect, may or may not be addressed by a specification, and may or may not be related to a failure. All defects are imperfections. Imperfections may be geometric, metallurgical, and cosmetic. In crystallography, it is a deviation from an ideal space lattice.
Impingement – It is a process resulting in a continuing succession of impacts between liquid or solid particles and a solid surface.
Impingement attack – It is the ‘form of erosion corrosion in aqueous liquids under high velocity or turbulent flow conditions associated on the metal surface causing repetitive disruption of protective films leading to accelerated localised corrosion’. It is the corrosion associated with turbulent flow of liquid. It can be accelerated by entrained gas bubbles.
Impingement corrosion – It is a form of erosion-corrosion normally associated with the local impingement of a high-velocity, flowing fluid against a solid surface.
Impingement erosion – It is the loss of material from a solid surface because of the liquid impingement.
Impingement umbrella – It is the partial screening of the surface of a solid sample subjected to solid impingement which sometimes occurs when some of the solid particles rebound from the surface and impede the motion of other impinging particles.
Impregnate – In reinforced plastics, it means to saturate the reinforcement with a resin.
Impregnated fabric – It is a fabric impregnated with a synthetic resin.
Impregnation – It is the treatment of porous castings with a sealing medium to stop pressure leaks. It is also the process of filling the pores of a sintered compact, normally with a liquid such as a lubricant. It is also the process of mixing particles of a non-metallic substance in a cemented carbide matrix, as in the diamond impregnated tools.
Impressed current – It is the direct current supplied by a device employing a power source external to the electrode system of a cathodic protection installation.
Impressed current cathodic protection (ICCP) – It is a technique which is widely used for the protection of buried pipelines and the hulls of ships immersed in seawater. A direct current electrical circuit is used to apply an electric current to the metallic structure. The negative terminal of the current source is connected to the metal needing protection. The positive terminal is connected to an auxiliary anode immersed in the same medium to complete the circuit. The electric current charges the structure with excess electrons and hence changes the electrode potential in the negative direction until the immunity region is reached. Impressed current cathodic protection is a specialized technology and can be very effective if correctly designed and operated. Typical materials used for anodes are graphite, silicon, titanium, and niobium plated with platinum.
Impressed current corrosion – It is the electro-chemical corrosion because of the action of an external source of electric current.
Impression – In electron microscopy, it is the reproduction of the surface contours of a sample formed in a plastic material after the application of pressure, heat, or both. In hardness testing, it is the imprint or dent made in the sample by the indenter of a hardness-measuring device.
Impression-die forging – It is a forging which is formed to the needed shape and size by machined impressions in specially prepared dies which exert three-dimensional control on the work-piece.
Impression replica – It is a surface replica made by impression. A replica is a reproduction of a surface in a material. It is normally accomplished by depositing a thin film of suitable material, such as plastic, onto the sample surface. This film is subsequently extracted and examined by transmission electron microscopy.
Impulse, resistance welding – it is a group of pulses which are occurring on a regular and which are separated only by an inter-pulse time.
Impulse response, impulse response function (IRF) – Impulse response function of a dynamic system is its output when presented with a brief input signal, called an impulse. Normally, an impulse response is the reaction of any dynamic system in response to some external change. In both cases, the impulse response describes the reaction of the system as a function of time (or possibly as a function of some other independent variable which parameterizes the dynamic behaviour of the system).
Impulse turbine – An impulse turbine has fixed nozzles which orient the steam flow into high-speed jets. These jets contain considerable kinetic energy, which the rotor blades, shaped like buckets, convert into shaft rotation as the steam jet changes direction. A pressure drop occurs across only the stationary blades, with a net increase in steam velocity across the stage. As the steam flows through the nozzle, its pressure falls from the inlet pressure to the exit pressure (atmospheric pressure, or more normally, the condenser vacuum). Because of this higher ratio of expansion of steam in the nozzle, the steam leaves the nozzle with a very high velocity. The steam leaving the moving blades has a large portion of the maximum velocity of the steam when leaving the nozzle. The loss of energy because of this higher exit velocity is normally called the ‘carry over velocity’ or ‘leaving loss’. In the impulse turbine, the fixed blades are quite different in shape from the moving ones since their job is to accelerate the steam until its velocity in the direction of rotation is around twice that of the moving blades. The moving blades are designed to absorb this impulse and to transfer it to the rotor in the form of kinetic energy. In this arrangement, majority of the pressure drop in each complete stage takes place in the fixed blades; the pressure drop through the moving blades is only sufficient to maintain the forward flow of steam. The quantity of energy transferred to the rotor in each stage is proportional to the change in absolute steam velocity in the direction of rotation.
Impurities -These are elements or compounds whose presence in a material is undesirable. In a chemical or material, it is minor constituent(s) or component(s) which is not included deliberately. It is normally to some degree or above some level, undesirable.
Inactive film binders – An inactive film binder is typically a liquid solution which uses surface tension to pull the material’s particle together. It can also be a dry solid which is mixed thoroughly with the material to be briquetted before a solvent such as water or alcohol is added. In this case, the solid acts as both lubricant and glue, forming a solid bridge between particles when the solvent dries. Examples of inactive binders are water, alcohol, oils, wheat flour, molasses, starches, casein, glucose, dextrin, alginates, and gum arabic.
Inactive matrix binders – An inactive matrix binder embeds the material to be briquetted in a matrix (or framework) of the binder. Some inactive matrix binders such as coal tar pitch need to be heated to reduce their viscosity during the briquetting process but it sets hard when allowed to cool. Examples of inactive matrix binders are petroleum asphalt, carnauba wax, paraffin, wood tar, colloidal alumina, and metal stearate.
Incandescent light bulb – It is a device which uses a fine wire filament heated by an electric current to make light and heat.
Incentive system – The primary purpose of an incentive system is to build a workforce of the employees in the organization which is not only motivated but also effective, efficient and accountable as well. Employees in the organization are geared to take up challenging tasks besides giving a healthy output. Besides this primary purpose, incentive system results into the improvements in the work culture of the organization by (i) creating a positive work environment, (ii) motivating higher performance, (iii) reinforcing desired behaviour, (iv) creating a culture of recognition, (v) increasing the employees’ morale, (vi) supporting the organization’s mission and values, (vii) increasing retention of the employees and decreasing their turnover, and (viii) encouraging loyalty and identification of the employees with the organization.
Incidence rate – Incidence rate is the total number of accidents multiplied by 1,000 and divided by the number of persons employed during the period
Incident – It is an unintended event, including operating errors, equipment failures, initiating events, accident precursors, near misses or other mishaps, or unauthorized act, malicious or non-malicious, the consequences or potential consequences of which are not negligible from the point of view of protection and safety. It is an unwanted event which, in different circumstances, can have resulted in harm to people, damage to property or loss to a process.
Incident investigation – It is the process of systematically gathering and analyzing information about an incident. This is done for the purposes of identifying causes and making recommendations to prevent the incident from happening again.
Incineration – It is a waste treatment process which involves the combustion of substances contained in waste materials. Industrial plants for waste incineration are commonly referred to as waste-to-energy facilities. Incineration and other high-temperature waste treatment systems are described as ‘thermal treatment’. Incineration of waste materials converts the waste into ash, flue gas and heat. The ash is mostly formed by the inorganic constituents of the waste and can take the form of solid lumps or particulates carried by the flue gas. The flue gases are to be cleaned of gaseous and particulate pollutants before they are dispersed into the atmosphere. In some cases, the heat that is generated by incineration can be used to generate electric power.
Incipient melting – It consists of heating of material into a two-phase liquid-solid region on the phase diagram so that some liquid is formed.
Inclinable press – It is a press which can be inclined to facilitate handling of the formed parts.
Inclined plane – It is also known as a ramp. It is a flat supporting surface tilted at an angle from the vertical direction, with one end higher than the other, used as an aid for raising or lowering a load. The inclined plane is one of the six classical simple machines, It is used to move heavy loads over Inclined position – It is the position of a pipe joint in which the axis of the pipe is at an angle of around 45-degree to the horizontal, and the pipe is not rotated during welding.
Inclined position with restriction ring – It is the position of a pipe joint in which the axis of the pipe is at an angle of around 45-degree to the horizontal, and a restriction ring is located near the joint. The pipe is not rotated during welding.
Inclinometer – It is an instrument used for measuring angles of slope, elevation, or depression of an object with respect to gravity’s direction. It is also known as a tilt indicator, tilt sensor, tilt meter, slope alert, slope gauge, gradient meter, gradiometer, level gauge, level meter, declinometer, and pitch and roll indicator. It measures both inclines and declines using three different units of measure namely degrees percentage points, and topos.
Included angle – It is a non-standard term for groove angle which is the total included angle of the groove between the work pieces.
Inclusion – Inclusions are non-metallic compounds and precipitates which form in steel during its production and processing and hence are the by-products of steelmaking which arise from different chemistries and processes. Inclusions can vary widely in size and composition, giving rise to a corresponding wide range of effects and mandating sophisticated analytical equipment for characterization. Inclusions are constituted by glass-ceramic phases embedded in steel metal matrix. Inclusion control is to promote the removal of inclusions from steel and to reduce their harmful effects on the quality and the processing of steel. It is an important aspect of the steelmaking practice. However, the presence of certain inclusion types can also yield beneficial effects in the steel. Inclusion is a physical and mechanical discontinuity occurring within a material or part, normally consisting of solid, encapsulated foreign material. Inclusions are frequently capable of transmitting some structural stresses and energy fields, but to a noticeably different degree than from the parent material. Inclusion is also the particles of foreign material in a metallic matrix. The particles are normally compounds, such as oxides, sulphides, or silicates, but can be of any substance which is foreign to (and essentially insoluble in) the matrix.
Inclusion count – It is the determination of the number, kind, size, and distribution of non-metallic inclusions in metals.
Inclusion engineering – The term ‘inclusions engineering’ means the design of the inclusions so as to alleviate their harmful effects on the product properties. Inclusion engineering does not refer to removal of inclusions but it refers to modify them either in terms of chemical composition or shape so that harmful effects of the inclusions can be converted to improve the steel properties. Inclusion engineering also involves distribution of inclusion uniformly in the matrix, so that composite properties can be generated in the product. In some cases, deliberate attempts are made to form very fine inclusions (e.g. nitrides, and carbo-nitrides inclusions in hardening steel). Such inclusion can form by reaction between tungsten, titanium, aluminum with oxygen, nitrogen, sulphur, or carbon.
Inclusion, stringer – It is an impurity, metallic or non-metallic, which is trapped in the ingot and elongated subsequently in the direction of working. It can be revealed during working or finishing as a narrow streak parallel to the direction of working.
Incoherent scattering – It is the deflection of electrons by electrons or atoms which results in a loss of kinetic energy by the incident electron.
Incomplete combustion – It is the partial oxidation of the combustible constituents of a fuel.
Incomplete fusion – In welding, it is the fusion which is less than complete.
Incomplete seam – It is the junction line of metal which has passed through a die forming a hollow profile (shape), separated and not completely rejoined. Flare testing is a method of evaluating weld integrity.
Inconel – It is a nickel-chromium-based superalloy often utilized in extreme environments where components are subjected to high temperature, pressure or mechanical loads. Inconel alloys are oxidation- and corrosion-resistant.
Incoterms – It is an abbreviation for the international commercial terms and is the registered trademark name given to these terms by International Chamber of Commerce (ICC). They are a series of three-letter trade terms related to common contractual sales practices. The Incoterms rules are intended mainly to clearly communicate the tasks, costs, and risks associated with the transportation and delivery of goods. They are published by the International Chamber of Commerce and are widely used in international commercial transactions. Incoterms are a set of rules which define the responsibilities of sellers and buyers for the delivery of goods under sales contracts for domestic and international trade. They apportion transportation costs and responsibilities associated with the delivery of goods between buyers (importers) and sellers (exporters) and reflect modern day transportation practices. Incoterms significantly reduce misunderstandings among trading parties and thereby minimize trade disputes and litigation.
Increment – It is an individual portion of material collected by a single operation of a sampling device from parts of a lot separated in time or space. Increments can be tested individually or combined (composited) and tested as a unit.
Incremental forging – It is a closed die forging process in which only a portion of the work piece is shaped during each of a series of press strokes. The process is similar to open die forging (cogging) of ingots, billets, thick plates, and shafts. In contrast to such operations, however, impression dies (not flat or V-shaped tooling) are utilized. The main applications of the technique are very large plan-area components of high temperature alloys for which die pressures can easily equal or exceed 140 MPa to 280 MPa. In such instances, part plan area is limited to around several thousands of square centimeters for the very large presses (50,000 tons). By forging, only a portion of the part at a time, however, reduces the press requirements.
Incremental step test – It is a technique which has been proposed as a time-saving method to determine the cyclic stress strain (CSS) curve with one sample is the incremental step test (IST). In each block the amplitude is first increased linearly with time up to a maximum amplitude, then decreased to zero (or a minimum amplitude value). This loading sequence (block) is applied repeatedly until a stabilized behaviour is established. Then the cyclic stress strain curve is obtained simply by connecting the load reversal points in the stress-strain course. It appears very doubtful that this test procedure gives a cyclic stress strain curve identical to that determined in single-step tests at different amplitudes. As described above, each amplitude leads to a characteristic dislocation distribution and arrangement that cannot be expected to exist at each single cycle of the incremental step test.
Incubation period – It is a period prior to the detection of corrosion while the metal is in contact with a corrodent. In cavitation and impingement erosion, it is the initial stage of the erosion rate-time pattern during which the erosion rate is zero or negligible compared to later stages. In cavitation and impingement erosion, it is the exposure duration associated with the initial stage of the erosion rate-time pattern during which the erosion rate is zero or negligible compared to later stages. Quantitatively, incubation period is sometimes defined as the intercept on the time or exposure axis, of a straight-line extension of the maximum slope portion of the cumulative erosion-time curve.
Indentation hardness – It is the resistance of a material to indentation. It is the normal type of hardness test, in which a pointed or rounded indenter is pressed into a surface under a substantially static load. It is also the resistance of a solid surface to the penetration of a second, normally harder, body under prescribed conditions. Numerical values used to express indentation hardness are not absolute physical
quantities, but depend on the hardness scale used to express hardness. Examples of indentation hardness are Brinell hardness, Knoop hardness, nano-hardness, Rockwell hardness, and Vickers hardness.
Indenter – In hardness testing, it is a solid body of prescribed geometry, normally chosen for its high hardness, which is used to determine the resistance of a solid surface to penetration.
Identification etching – It is the etching to expose particular micro-constituents with all others remain unaffected.
Independent t-test – It is a statistical procedure for comparing measurements of mean scores in two different groups or samples. It is also called the independent samples t-test.
Index of refraction – It is the ratio of the phase velocity of mono-chromatic light in a vacuum to that in a specified medium. Index of refraction is normally a function of wave length and temperature.
Indicated mineral resource – An indicated mineral resource is that part of a mineral resource for which quantity, grade (or quality), densities, shape, and physical characteristics are estimated with sufficient confidence to allow the application of modifying factors in sufficient detail to support mine planning and evaluation of the economic viability of the deposit. Geological evidence is derived from adequately detailed and reliable exploration, sampling, and testing gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes, and is sufficient to assume geological and grade (quality) continuity between points of observation where data and samples are gathered. An indicated mineral resource has a lower level of confidence than that applying to a measured mineral resource and can only be converted to a probable ore reserve.
Indices, Miller-Bravais – These are the indices which are used for the hexagonal system. They involve use of a fourth axis, a3, coplanar with and at 120-degree to a1 and a2.
Indices, Miller (for lattice planes) – These are the reciprocals of the fractional intercepts which a plane makes on the three axes. The symbols are (hkl).
Indigenous inclusion – It occurs within the liquid steel, precipitating out during cooling and solidification. The inclusions belonging to this class result from additives to the steel. They are deoxidation products or precipitated inclusions during cooling and solidification of steel. Alumina inclusions in low carbon aluminum killed (LCAK) steel, and silica inclusions in silicon-killed steel are generated by the reaction between the dissolved oxygen and the added aluminum and silicon deoxidants are typical deoxidation inclusions. Indigenous inclusion is an inclusion which is native, innate, or inherent in the molten metal treatment. Indigenous inclusions include sulphides, nitrides, and oxides derived from the chemical reaction of the molten metal with the local environment. Such inclusions are small and need microscopic magnification for identification.
Indirect-arc furnace – It is an electric arc furnace in which the metallic charge is not one of the poles of the arc.
Indirect contact condensation recovery – Indirect contact condensation recovery units cool gases to around 40 deg C. In this range, the water vapour in gases condenses almost completely. Indirect contact exchangers consist of a shell and tube heat exchangers. They can be designed with stainless steel, glass, Teflon, or other advanced materials.
Indirect costs – It is the cost which is not directly associated with the production of identifiable goods or services. It is also called burden costs or overhead costs.
Indirect (backward) extrusion – It is the extrusion, in which the die is at the ram end of the stock and the product travels in the direction opposite that of the ram, either around the ram (as in the impact extrusion of cylinders such as cases for dry cell batteries), or up through the centre of a hollow ram.
Indirect sintering – It is a process whereby the heat needed for sintering is generated outside the body and transferred to the compact by conduction, convection, and radiation etc.
Individuals – It is the conceivable constituent parts of a population.
Induced draft fan – It is a fan exhausting hot gases from the heat absorbing equipment.
Induced polarization – It is a method of ground geophysical surveying using an electrical current to determine indications of mineralization.
Induction bonding – It is a secondary joining process for thermoplastic composite parts in which a metallic susceptor is placed in the bond line and an induction coil is used to heat the joint above the melt temperature of the thermoplastic matrix.
Induction brazing – It is a brazing process in which the heat needed is got from the resistance of the work-pieces to induced electric current.
Induction coil – It is a type of electrical transformer, which is used to produce high-voltage pulses from a low-voltage direct current supply. To create the flux changes it is necessary to induce voltage in the secondary coil, the direct current in the primary coil is repeatedly interrupted by a vibrating mechanical contact called an interrupter.
Induction furnace – Induction furnace consists basically of a crucible, inductor coil, and shell, cooling system and tilting mechanism. The crucible is formed from refractory material, which the furnace coils is lined with. This crucible holds the charge material and subsequently the melt. The choice of refractory material depends on the type of the charge and basically consist of either acidic, basic or neutral refractories. Induction furnace is an alternating current electric furnace in which the main conductor is coiled and generates, by electro-magnetic induction, a secondary current which develops heat within the metal charge.
Induction generator – It is a type of generator where the rotating field winding is excited by induction from the stationary armature winding.
Induction hardening – It is a surface-hardening process in which only the surface layer of a suitable ferrous work-piece is heated by electro-magnetic induction to above the upper critical temperature and immediately quenched.
Induction heating – It is the heating by combined electrical resistance and hysteresis losses induced by subjecting a metal to the varying magnetic field surrounding a coil carrying alternating current.
Induction melting – It is the melting in an induction furnace.
Induction motor – It is a type of motor where the rotating field winding is excited by induction from the stationary armature winding. The induction motor is an alternating current motor which differs in several ways from the direct current motor, but works on the same principle. Analysis indicates that the stator flux and the rotor flux rotate in synchronism in the air gap, and the two flux distributions are displaced from each other by a torque-producing displacement angle. The torque is produced because of the tendency of the two flux distributions to align with each other. It is highlighted at the outset that alternating current motors are not fundamentally different from direct current motors. Their construction details are different, but the same fundamental principles underlie their operation. The induction motor is the most rugged and the most widely used motor in the industry. Like the direct current motor, the induction motor has a stator and a rotor mounted on bearings and separated from the stator by an air gap. However, in the induction motor, both stator winding and rotor winding carry alternating current. The alternating current is supplied to the stator winding directly and to the rotor winding by induction, hence the name induction motor. In induction motor, the stator windings serve as both armature windings and field windings. When the stator windings are connected to an alternating current supply, flux is produced in the air gap and revolves at a fixed speed known as synchronous speed. This revolving flux induces voltage in the stator windings as well as in the rotor windings. If the rotor circuit is closed, current flows in the rotor winding and reacts with the revolving flux to produce torque. The steady-state speed of the rotor is very close to the synchronous speed. The rotor can have a winding similar to the stator or a cage-type winding. The latter is formed by placing aluminum or copper bars in the rotor slots and shorting them at the ends by means of rings.
Induction pressure welding – It is a solid -welding, obtained by the use of high frequency induction heating and by simultaneous application of pressure. Oxidation is avoided by purging with hydrogen gas. The surfaces to be joined are heated by induction current produced by an inductor in series with two capacitors, powered by a transformer with two high frequency alternators. The induced current flows in a longitudinal loop along the edges to be welded, heating them uniformly through their thickness over a certain length. Forging rolls, then weld together the fused lips, leaving a slight external flash, which is removed afterwards. The normal speed of welding depends on the power supplied. Induction pressure welding is extensively used in joining boiler grade chtomiun-molybdenum steel tubes.
Induction regulator – It is a kind of variable transformer which provides stepless control of the output by changing the coupling between two coils.
Induction sintering – It is the sintering in which the needed heat is generated by subjecting the compact to electro-magnetic conduction.
Induction soldering – It is a soldering process in which the heat needed is got from the resistance of the work-pieces to induced electric current.
Induction tempering – It is the tempering of steel using low-frequency electrical induction heating.
Induction turbine – This is the turbine in which low pressure steam is introduced at an intermediate stage for the production of additional power.
Induction welding – It is a welding process which produces coalescence of metals by the heat got from the resistance of the work-pieces to the flow of induced high-frequency welding current with or without the application of pressure. The effect of the high-frequency welding current is to concentrate the welding heat at the desired location.
Induction work coil – It is the inductor used in the processes of induction heating and melting as well as induction welding, brazing, and soldering.
Inductive coupling – It is the transfer of energy between two circuits through the magnetic field which passes through both.
Inductively coupled plasma (ICP) – It is an argon plasma excitation source for atomic emission spectroscopy or mass spectroscopy. It is operated at atmospheric pressure and sustained by inductive coupling to a radio-frequency electromagnetic field.
Inductively coupled plasma atomic emission spectrometry (ICP/AES) – It is an analytical technique used for the detection of trace elements. It uses the inductively coupled plasma to produce excited atoms and ions that emit electromagnetic at wavelengths characteristic of a particular element. The intensity of this emission is indicative of the concentration of the element within the sample. Inductively coupled plasma atomic emission spectrometer consists of two parts namely (i) the inductively coupled plasma, and (ii) the optical spectrometer. The inductively coupled plasma torch consists of 3 concentric quartz glass tubes. The output of the radio frequency generator surrounds part of this quartz torch. Argon gas is typically used to create the plasma. The radio frequency generated and maintained argon plasma, portions of which are as hot as 10,000 deg K, excites the electrons. The plasma is used to atomize and ionize the elements in the sample. When the electrons return to ground state at a certain spatial position in the plasma, they emit energy at the specific wave-lengths peculiar to the elemental composition of the sample. Light emitted from the plasma is focused through a lens and passed through an entrance slit into the spectrometer. There are two types of spectrometers used in the inductively coupled plasma atomic emission spectrometer analysis. These are namely (i) sequential (mono-chromator), and (ii) simultaneous (poly-chromator). Inductively coupled plasma mass spectrometry (ICP-MS) is a very powerful tool for trace (ppb, parts per billion-ppm) and ultra-trace (parts per quadrillion -parts per billion) elemental analysis.
Inductive output tube – It is a high power, high frequency amplifier tube, which in some forms is capable of megawatt pulses at hundreds of megahertz.
Inductor – It is a device consisting of one or more associated windings, with or without a magnetic core, for introducing inductance into an electric circuit.
Induration – During the induration, heat hardening of green pellets is carried out. Induration of green pellets consists of three main steps namely (i) drying of green pellets, (ii) firing of pellets at around 1300 deg C to sinter the iron oxide particles, and (iii) cooling of hot pellets before discharging.
Industrial accident – It is an unintended event due to an unsafe act or unsafe condition or a combination of both, which may or may not result in property damage, personal injury, work interruption, product damage or a combination of these.
Industrial atmosphere – It is an atmosphere in an area of heavy industry with soot, fly ash, and sulphur compounds as the principal constituents.
Industrial automation – It is the general practice of automatic control applied to industrial operations.
Industrial chromium plating – It is produced by electro-deposition from a solution containing chromic acid (CrO3) and a catalytic anion in proper proportion. The metal so produced is extremely hard and corrosion resistant. The process is used for applications where excellent wear and / or corrosion resistance is needed. This includes products such as piston rings, shock absorbers, struts, brake pistons, engine valve stems, cylinder liners, and hydraulic rods. Other applications are for aircraft landing gears, textile and gravure rolls, plastic rolls, and dies and moulds.
Industrial control panel enclosures – These are robust, protective cabinets which serve as a centralized location for housing various electrical components. These include, but are not limited to switches, drives etc.
Industrial computed tomography – It is, in a general sense, is an imaging technique which generates an image of a thin, cross-sectional slice of a test piece. The computed tomography imaging technique differs from other imaging methods in that the energy beam and the detector array in computed tomography systems lie in the same plane as the surface being imaged. This is unlike typical imaging techniques, in which the energy beam path is perpendicular to the surface being imaged. Moreover, because the plane of a computed tomography image is parallel with the energy beam and detector scan path, computed tomography systems need a computing procedure to calculate, locate, and display the point-by-point relative attenuation of the energy beam passing through the structures within the thin, cross-sectional slice of the test piece.
Industrial design – It is the first broadly functional description of a product with emphasis on visual and aesthetic features (shape, color, texture).
Industrial electrical control panels – These panels are a special type of assembly which contains at least two power circuits, control circuits, or any combination of power and control circuit components. These panels are factory-based wired assemblies of industrial control equipment, such as motor controllers, switches, relays, and auxiliary devices which control equipment in the industrial environment. These types of industrial control panels can include a means of disconnecting that which it is powering, as well as a protective device of the branch-circuit. Industrial control panels are intended for general-use industrial applications for the control of industrial machineries, lighting, motors, or pump loads or a combination of these loads, and are intended for installation in ordinary locations.
Industrial engineering – It is an engineering discipline which is concerned with the optimization of complex processes, systems, or organizations by developing, improving and implementing integrated systems of people, money, knowledge, information and equipment. It is central to manufacturing operations. Industrial engineering personnel use specialized knowledge and skills in the mathematical, physical, and social sciences, together with engineering analysis and design principles and methods, to specify, predict, and evaluate the results obtained from systems and processes.
Industrial fans and blowers – These are machines, whose primary function is to provide a large flow of air or gas to various processes. This is achieved by rotating a number of blades, connected to a hub and shaft, and driven by a motor or turbine. The flow rates of these fans range from around 5.7 cubic meter per minute to 57,000 cubic meter per minute. A blower is another name for a fan which operates where the resistance to the flow is primarily on the downstream side of the fan.
Industrial gases – The term ‘Industrial gas’ is referred to a group of gases which are specifically produced for use in a variety of industrial processes. They are distinct from the fuel gases. However, acetylene is sometimes considered as industrial gas. Speciality gases such as neon, krypton, xenon and helium are sometimes considered under the category of industrial gases. Industrial gases are produced and supplied in both gas and liquid form and transported in cylinder, as bulk liquid or in pipelines as gas. Common industrial gases normally used in industry are oxygen, nitrogen, argon, and hydrogen.
Industrial injury – An injury arising from an industrial accident which occurs whilst a person is working for the organization or on the organization’s premises for purposes in connection with or arising out of and in the course of the person’s work, but which may not necessarily result in absence from work.
Industrial minerals – These are non-metallic, non-fuel minerals used in the chemical and manufacturing industries. Examples are asbestos, gypsum, salt, graphite, mica, gravel, building stone, and talc etc.
Industrial wastewater – Industrial wastewater also sometimes called effluent is the aqueous discard which results after the water is used for the industrial purposes. Industrial wastewater is the result of different substances which get dissolved or suspended in water during its used. Industrial wastewater means the water or liquid which carries waste from industrial processes. It can result from any process or activity of industry which uses water as a reactant or for transportation of heat or materials. Industrial wastewater frequently presents physico-chemical characteristics which need treatment before its release to the environment or the sewer system. Further, a number of different industrial activities contribute to emissions of heavy metals, with the majority of industrial releases originating from metal processing facilities (iron and steel, and non-ferrous metals production).
Inelastic electron scatter – It is the deflection of electrons by electrons or atoms which results in a loss of kinetic energy by the incident electron.
Inelastic scattering – It is a collision or interaction which changes the energy of an incident particle.
Inert anode – It is an anode which is insoluble in the electrolyte under the conditions prevailing in the electrolysis.
Inert filler – It is a material added to a plastic to alter the end-item properties through physical rather than chemical means.
Inert gas – It is a gas, such as helium, argon, or nitrogen, which is stable, does not support combustion, and does not form reaction products with other materials. In welding, it is a gas which does not normally combine chemically with the base metal or filler metal.
Inert gas arc welding – It is a non-standard term for gas metal arc welding. It is an arc welding in which coalescence of metals is produced by heating them with an arc between a continuous filler metal electrode and the work-pieces. Shielding is achieved entirely from an externally supplied inert gas.
Inert gas atomization – It is a specialized technique used to produce metal powders with a high degree of purity and uniformity. It involves the conversion of molten metal into droplets and their subsequent solidification into fine particles under the influence of an inert gas, such as nitrogen or argon.
Inert gaseous constituent – It is the incombustible gases such as nitrogen which can be present in a fuel.
Inert gas fusion – It is an analytical technique for determining the concentrations of oxygen, hydrogen, and nitrogen in a sample. The sample is melted in a graphite crucible in an inert gas atmosphere and individual component concentrations are detected by infrared or thermal conductive methods.
Inert gas tungsten arc welding – It is a non-standard term for gas tungsten arc welding. It is an arc welding coalescence of metals is produced by heating them with an arc between a tungsten (non-consumable) electrode and the work. Shielding is achieved from an inert gas or inert gas mixture. Pressure and filler metal may or may not be used.
Inertia – It a property of matter by which it remains at rest or in uniform motion in the same straight line unless acted upon by some external force. It is the natural tendency of an object in motion to stay in motion and object at rest to stay at rest, unless a force causes its velocity to change.
Inertia block in equipment foundation – It is used for small moving blocks, and equipments etc. In this situation, small dynamic equipments are normally designed with a supporting inertia block to alter natural frequencies away from equipment operating speeds and resist amplitudes by increasing the resisting inertia force.
Inference – Inference is the process of deducing properties of the underlying distribution or population, by analysis of data. It is the process of making generalizations from the sample to a population.
Inferential analyzing method – It uses a small sample to conclude a bigger population. It means, data from a subject sample of the world is used to test a general theory about its nature. The types of data sets which can be used in this method are observational, retrospective data set, and cross-sectional time study.
Inferential statistics – The body of statistical techniques concerned with making inferences about a population based on drawing a sample from it.
Inferred mineral resource – An inferred mineral resource is that part of a mineral resource for which quantity and grade (or quality) are estimated on the basis of limited geological evidence and sampling. Geological evidence is sufficient to imply but not verify geological and grade (or quality) continuity. It is based on exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes. An inferred mineral resource has a lower level of confidence than that applying to an indicated mineral resource and is not to be converted to an ore reserve. It is reasonably expected that the majority of Inferred mineral resources can be upgraded to Indicated mineral resources with continued exploration.
Infiltrate – It is the material used to infiltrate a porous sinter. The infiltrant as positioned on the compact is called a slug.
Infiltration – It is the process of filling the pores of a sintered or unsintered compact with a metal or alloy of lower melting temperature.
Infinite impulse response – It is a filter which, mathematically, never gets to a zero effect of an impulse at its input, though practically the response can become negligible after a definite time.
Inflating roll method (Variable crown roll method) – In case of the work roll with a longer roll barrel length, the effect of work roll bending (WRB) is less likely to transmit to the strip width central region in work roll bending shape control. The strip shape control effect can be maintained by combining the work roll bending method with the method by which a back-up-roll is partially inflated in the roll barrel direction for shape control. If the shape control performance can be maintained by using an inflating roll as a back-up roll, it is possible to eliminate the need to process the work roll to form a convex-curved shape in strip centre region. This type of roll reduces the chance of sharp uneven contact between the strip and the work roll, and is effective especially when the quality of the strip surface needs to always be superior.
Inflection point – It is the position on a curved line, such as a phase boundary, at which the direction of curvature is reversed.
Informal standards – These standards are by SDOs (standards development organizations) such as American Society for Testing and Materials (ASTM), American Society of Mechanical Engineers (ASME), Institute of Electrical and Electronics Engineers (IEEE), and Society of Automobile Engineers (SAE) etc.
Information appliance – Conceptually, It is an embedded computer system with a specialized user interface designed to simplify one task, such as e-mail or photos, A modern smart phone approaches this concept.
Information / measurement standards – Such standards describe test and measurement methods for describing, quantifying and evaluating product attributes such as materials, processes and functions.
Information technology (IT) – It is a set of related fields that encompass computer systems, software, programming languages, and data and information processing, and storage. Information technology forms part of information and communications technology (ICT).
Information technology system (IT system) – It is normally an information system, a communications system, or, more specifically speaking, a computer system, including all hardware, software, and peripheral equipment which is operated by a limited group of users. Information technology systems play an important role in facilitating efficient data management, improving communication networks, and supporting organizational processes across different industries.
Infrared – It is the part of the electro-magnetic spectrum between the visible light range and the radar range. Radiant heat is in this range, and infrared heaters are frequently used in the thermoforming and curing of plastics and composites. Infrared analysis is used for identification of polymer constituents.
Infrared analyzer – It is an atmosphere-monitoring device which measures a gas (normally carbon mono-oxide, carbon di-oxide, and methane) presence based on specific wave-length absorption of infrared energy.
Infrared brazing – It is a brazing process in which the heat needed is furnished by infrared radiation.
Infrared (IR) radiation – It is electro-magnetic radiation (EMR) with wave-lengths longer than those of visible light but shorter than microwaves. The infrared spectral band begins with waves which are just longer than those of red light (the longest waves in the visible spectrum), so infrared is invisible to the human eye. Infrared normally understood to include wave-lengths from around 750 nano-meters (400 tera-hertz) to 1 millimeter (300 giga-hertz). Infrared is normally divided between longer-wavelength thermal infrared, emitted from terrestrial sources, and shorter-wavelength infrared or near-infrared, part of the solar spectrum. Longer infrared wave-lengths (30 micrometers to 100 micrometers) are sometimes included as part of the tera–hertz radiation band. Almost all black-body radiation from objects near room temperature is in the infrared band. As a form of electro-magnetic radiation, infrared carries energy and momentum, exerts radiation pressure, and has properties corresponding to both those of a wave and of a particle, the photon.
Infrared soldering – It is a soldering process in which the heat needed is furnished by infrared radiation.
Infrared spectrometer – It is a device which is used to measure the amplitude of electro-magnetic radiation of wave-lengths between visible light and micro-waves.
Infrared spectroscopy – It is the study of the interaction of material systems with electro-magnetic radiation in the infrared region of the spectrum. The technique is useful for determining the molecular structure of organic and inorganic compounds by identifying the rotational and vibrational energy levels associated with the different molecules.
Infrared spectrum – It the range of wave-lengths of infrared radiation. It is also a display or graph of the intensity of infrared radiation emitted or absorbed by a material as a function of wave-length or some related parameter.
Infrared thermometer – It is a non-contact radiant energy detector. The amount of radiant energy emitted is proportional to the temperature of the object. Non-contact thermometers measure the intensity of the radiant energy and produce a signal proportional to the target temperature. The physics behind this broadcasting of energy is called Planck’s law of thermal radiation. This radiated energy covers a wide spectrum of frequencies, but the infrared spectrum is normally used for temperature measurement. IR thermometers capture the invisible infrared energy which is naturally emitted from all objects warmer than absolute zero (0 Kelvin). Infrared radiation is part of the electro-magnetic spectrum which includes gamma rays, X-rays, micro-waves, ultra-violet, visible light, and radio waves. Infrared falls between the visible light of the spectrum and radio waves. Infrared wavelengths are normally expressed in micrometers with the infrared spectrum extending from 0.65 micrometers to 1,000 micrometers. In practice, the 0.65 micrometers to 14 micrometers band is used for jnfrared temperature measurement over a range from -50 deg C to 3,000 deg C.
Infrasound – It is sometimes referred to as low frequency sound. It describes sound waves with a frequency below the lower limit of human audibility (normally 20 hertz). Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure is to be sufficiently high. Although the ear is the primary organ for sensing low sound, at higher intensities it is possible to feel infrasound vibrations in various parts of the body.
Ingate – It is the portion of the runner in a mould through which molten metal enters the mould cavity. The generic term is sometimes applied to the entire network of connecting channels which conduct metal into the mould cavity.
Ingot – It is a casting of simple shape, suitable for hot working or remelting. It is a casting intended for subsequent rolling, forging, or extrusion.
Ingot iron – It is commercially pure iron.
Ingot, extrusion – It is a cast form which is solid or hollow, normally cylindrical, suitable for extruding.
Ingot, fabricating – It is a cast form suitable for subsequent working by such methods as rolling, forging, extruding, and so on (rolling ingot, forging ingot, extrusion ingot).
Ingot, forging – It is a cast form intended and suitable for subsequent working by the forging process.
Ingot metallurgy – It consists of the metallurgical aspects which are involved during the casting of molten metal in ingot moulds.
Ingot, remelt – It is a cast form intended and suitable for remelting, normally for producing castings.
Ingot, rolling – It is a cast form suitable for rolling.
Ingot steel – It is a form of semi-finished steel. Liquid steel is teemed (poured) into ingot moulds, where it slowly solidifies. Once the steel is solid, the mould is stripped, and the ingot is then ready for subsequent rolling or forging.
Ingress protection (IP) ratings – These are the ratings, which grade the resistance of an enclosure against the intrusion of dust or liquids.
Inherent diaphragm pressure range – It is the high and low values of pressure applied to the diaphragm to produce rated valve plug travel with atmospheric pressure in the valve body. This range is frequently referred to as a bench set range since it is the range over which the valve strokes when it is set on the work bench.
Inherent discontinuities – Inherent discontinuities refer to the discontinuities which originate during the initial casting process of the liquid metal such as casting of ingots, continuous casting of semi-finished products, and casting of parts of any given shape in the foundries. Some of the initial casting discontinuities are removed by chopping or grinding but some of them remain and further change their shape and nature during the subsequent processing of the material.
Inherent flow characteristic – It is the relationship between the flow rate and the closure member travel as it is moved from the closed position to rated travel with constant pressure drop across the valve.
Inhibitor – It is a substance which selectively retards some specific chemical reaction, e.g., corrosion. Pickling inhibitors retard the dissolution of metal without hindering the removal of scale from steel. Corrosion inhibitors are chemical substances which stop or retard corrosion of the metallic surface when added to the corrosive media in small quantities. An example in boiler work is the use of an inhibitor, when using acid to remove scale, to prevent the acid from attacking the boiler metal.
Initial graphics exchange specification (IGES) It is a vendor-neutral file format that allows the digital exchange of information among computer-aided design (CAD) systems. Using initial graphics exchange specification, a computer aided design user can exchange product data models in the form of circuit diagrams, wireframe, freeform surface, boundary (B-rep) or solid modeling (constructive solid geometry, CSG) representations. Applications supported by initial graphics exchange specification include traditional engineering drawings, models for analysis, and other manufacturing functions.
Initial graphics exchange standard (IGES) – It is a protocol for transferring graphics data between CAD systems.
Initial modulus – It is the slope of the initial straight portion of a stress-strain or load-elongation curve.
Initial pitting – It is the surface fatigue which is occurring during the early stages of gear operation, associated with the removal of highly stressed local areas and running-in.
Initial recovery – It is the decrease in strain in a solid during the removal of force before any creep recovery takes place. It is normally determined at constant temperature. It is sometimes referred to as instantaneous recovery.
Initial strain – It is the strain in a sample immediately upon achieving the given loading conditions in a creep test (before creep occurs). It is sometimes referred to as instantaneous strain.
Initial stress – It is the stress which is produced by strain in a sample immediately on achieving the given constant-strain conditions in a stress-relaxation test before stress-relaxation occurs. It is sometimes referred to as instantaneous stress.
Initial tangent modulus – It is the slope of the stress-strain curve at the beginning of loading.
Initiating event – It is the term used in safety engineering to refer to an initiating cause, when assessing consequences and outcomes. An initiating event can be defined as a challenge to plant operation. ‘Event tree analysis’ involves the analysis of initiating events and their consequences.
Initiation of stable crack growth – It is the initiation of slow stable crack advance from the blunted crack tip.
Initiation phase, project – Initiation phase of a project is the first phase when the design and engineering activities start. During this phase feasibility studies for the project are carried out for firming of the initial decision of setting up of the plant. This is the phase when various approvals are taken for the implementation of the project. One of the important approvals during this phase is the environmental clearance for the project. This clearance needs preparation of a study report for the environment impact assessment (EIA) and environment management plan (EMP). During this phase the project concepts are determined and a plot plan for the selected facilities is made. The technologies to be adopted are selected after assessing various available technologies, requirements of input materials, utilities, and power are estimated after carrying out preliminary balancing of capacities, materials, energies, and utilities etc. The suitability of the site location is also established in this phase after the study of the infrastructure development need for the project. This is the phase when the requirements of enabling facilities needed during the project implementation are determined. These enabling facilities include (i) site preparation including its leveling, (ii) road and / or rail approach for the selected site, (iii) building requirements for administration during construction, (iv) facilities for construction stores, (v) communication need during construction, (vi) requirements of water, power, and other utilities needed during project implementation, and (vii) housing facilities needed for the construction workers etc. Basic engineering for these enabling facilities starts during this phase.
Initiator – It consists of the peroxides used as sources of free radicals. These peroxides are used in free-radical polymerizations, for curing thermosetting resins, as cross-linking agents for elastomers and polyethylene, and for polymer modification.
Injection – It is the process of forcing molten metal into the die casting die. It is also the process of injecting a powdered material in the molten metal filled in a ladle.
Injection lances – These lances are used for injecting either oxygen or auxiliary fuels into the blast furnace through tuyeres. These lances are normally inserted in blow-pipes.
Injection metallurgy – It is used in conjunction with ladle furnaces. It is used to refine molten steel. In injection metallurgy, desulphurizing reagents are injected into the ladle through a lance using argon gas as a carrier, which helps remove sulphur. Ladle furnaces are used to reheat, stir, and refine steel in a ladle.
Injection moulding – It is the injection of molten metal or other material under pressure into moulds.
Injection moulding (ceramics) – It is a process for forming ceramic articles in which a granular ceramic-binder mix is heated until softened and then forced into a mold cavity, where it cools and resolidifies to produce a part of the desired shape.
Injection moulding (metals) – It is a process similar to plastic injection moulding using a plastic-coated metal powder of fine particle size (around 10 micrometer).
Injection molding (plastics) – It is the method of forming a plastic to the desired shape by forcing the heat-softened plastic into a relatively cool cavity under pressure.
Injection refining (IR) process – In this process, first lime and then calcium silicide are fed pneumatically through a vertical lance into the teeming ladle. A refractory-lined hood placed over the surface of the steel prevents ingress of atmospheric oxygen. As the relatively large lime particles rise through the melt, they cleanse it by collecting the essentially stationary smaller-diameter (around 1 micrometer to 10 micrometers) products of deoxidation.
Injector – It is a device utilizing a steam jet to entrain and deliver feed water into a boiler.
Injury – It consists of an abnormal condition or disorder, such as cuts, fractures, sprains, amputations, skin diseases, respiratory disorders, and several other types of bodily harm. The definition encompasses a wide range of situations, including accidents, injuries from repetitive motions, exposure to harmful substances, and illnesses caused by work activities.
Injury analysis – It is the process of systematically evaluating injury statistics to identify trends.
Ink jet printing – It is a method of printing where tiny drops of ink are formed into a number, letter or image and are then sprayed onto the surface to be printed.
Inlet port – It is the end of a valve which is connected to the upstream pressure zone of a fluid system. Inner seat ring – It is the inner part of a two-piece valve seat assembly.
Inner sheath (for multi-core cables) – The laid-up cores are surrounded by an inner sheath of any of the two types namely (i) extruded poly vinyl chloride (PVC) compound (for armoured cables), and (ii) wrapping of poly vinyl chloride / plastic tapes for unarmoured cables. Inner sheath is also known as bedding in case of armoured cables.
Inner volume, blast furnace – It is the total inner volume of the blast furnace between the hearth bottom and the level of the top ring.
Innovation -It is normally considered as new idea, creative thought, and new imagination in form of device or method. It is often viewed as the application of better solutions which meet new requirements, unarticulated needs, or existing needs of the market. It is also considered as the process of translating an idea or invention into a good or service which creates value or for which customers are going to pay. It often results when ideas are applied by the organization in order to further satisfy the needs and expectations of the customers. It is crucial to the continuing success of any organization. Hence the need of innovation is essential for the organization to be successful.
Inoculant – It is the material which, when added to the molten metal, modifies the structure and hence changes the physical and mechanical properties to a degree not explained on the basis of the change in composition resulting from their use. Ferro-silicon-base alloys are normally used to inoculate gray irons and ductile irons.
Inoculation – It is the addition of a material to molten metal to form nuclei for crystallization.
Inorganic – It is being or composed of matter other than hydrocarbons and their derivatives, or matter which is not of plant or animal origin.
Inorganic acid – It is a mineral acid which is derived from one or more inorganic compounds, as opposed to organic acids which are acidic, organic compounds. All mineral acids form hydrogen ions and the conjugate base when dissolved in water.
Inorganic chemistry – It deals with synthesis and behaviour of inorganic and organometallic compounds. This field covers chemical compounds which are not carbon-based, which are the subjects of organic chemistry. The distinction between the two disciplines is far from absolute, as there is much overlap in the subdiscipline of organometallic chemistry. It has applications in every aspect of the industry.
Inorganic coatings – Inorganic coatings are frequently used for providing a barrier between the atmosphere and the metal. Enamel, glass linings, and conversion coatings are all inorganic coatings. The treatment transforms the metal surface into a metallic oxide film or a compound which is more resistant to corrosion than the natural oxide film and provides an effective base or additional safety key, such as paints.
Inorganic compound – It is a substance in which two or more chemical elements (normally other than carbon) are combined, nearly always in definite proportions. The inorganic compound lacks carbon–hydrogen bonds.
Inorganic pigments – These are natural or synthetic metallic oxides, sulphides, and other salts which impart heat and light stability, weathering resistance, colour, and migration resistance to plastics.
Inorganic zinc-rich paint – It is the coating containing a zinc powder pigment in an inorganic vehicle.
Inorganic wastewater – Inorganic wastewater is produced mainly in the coal and steel industry, in the non-metallic minerals industry, and in commercial organizations and industries for the surface processing of metals (iron picking works and electro-plating plants). These wastewaters contain a large proportion of suspended matter, which can be eliminated by sedimentation, frequently together with chemical flocculation through the addition of iron or aluminum salts, flocculation agents and some kinds of organic polymers. The purification of warm and dust-laden waste gases from blast furnaces, converters, cupola furnaces, refuse and sludge incineration plants, and aluminum works results in wastewater containing mineral and inorganic substances in dissolved and undissolved form.
Input/output (I/O) – In computing, it is the communication between an information processing system, such as a computer, and the outside world, such as another computer system, peripherals, or a human operator. Inputs are the signals or data received by the system and outputs are the signals or data sent from it. The term can also be used as part of an action, to ‘perform I/O’ is to perform an input or output operation. I/O devices are the pieces of hardware which are used by a human (or other system) to communicate with a computer.
Inrush current, input surge current – It is the maximal instantaneous input current drawn by an electrical device when first turned on. Alternating-current electric motors and transformers can draw several times their normal full-load current when first energized, for a few cycles of the input waveform. Power converters also frequently have inrush currents much higher than their steady-state currents, because of the charging current of the input capacitance. The selection of over-current-protection devices such as fuses and circuit breakers are made more complicated when high inrush currents are to be tolerated. The over-current protection is to react quickly to overload or short-circuit faults but is not to interrupt the circuit when the (normally harmless) inrush current flows.
Insert – It is a part formed from a second material, normally a metal, which is placed in the moulds and appears as an integral structural part of the final casting. It is also a removable portion of a die or mould. In case of composites, it is an integral part of a plastic moulding consisting of metal or other material which can be moulded or pressed into position after the molding is completed.
Insert die – It is a relatively small die which contains part or all of the impression of a forging and which is fastened to a master die block.
Inserted-blade cutters – These are the cutters having replaceable blades which are either solid or tipped and are normally adjustable.
In-service monitoring – In-service monitoring of industrial manufacturing operations is the type of service corrosion testing which presents the highest challenge and for which there is a great need. In such operations, the expense of corrosion problems can be huge and the risks devastating. Corrosion monitoring has become an important aspect of the design and operation of modern industrial plants because it enables plant engineering and management personnel to be aware of the damage caused by corrosion and the rate of the deterioration. The term monitoring, as used in this context, includes any technique for evaluating the progress or rate of corrosion.
Inside diameter (ID) – Inside diameter of a hollow circular object, like a pipe, is a measurement of the distance of a straight line from one point on the inner wall of the object, through its center, to an opposite point also on the inside.
Inside screw, rising stem – It is the common term for any valve design in which the stem threads are exposed to the fluid below the packing and the stem rises up through the packing when the valve is opened.
Inspection – It is an organized examination or formal evaluation exercise. In production, it involves the measurements, tests, measuring gauges and test equipments applied to certain characteristics in regard to a material or a product. It is normally non-destructive. It consists of the activity such as witnessing the measurement, examination, testing or gauging of one or more characteristics of an entity and comparing the results with specified requirements in order to establish whether the results are in order and to establish whether conformity is achieved for each characteristic. Inspection is an important tool to achieve quality concept. It is necessary to assure confidence to the producer and aims satisfaction to the customer. Inspection is an indispensable tool of the present-day production processes. It helps to control quality, reduces production costs, eliminate scrap losses, and assignable causes of defective work.
Inspection lot – For non-heat-treated tempers, it is an identifiable quantity of material of the same mill form, alloy, temper, section, and size submitted for inspection at one time. For heat treated tempers, it is an identifiable quantity of material of the same mill form, alloy, temper, section, and size traceable to a heat treat lot or lots and submitted for inspection at one time. (For sheet and plate, all material of the same thickness is considered to be of the same size).
Inspection, product – It refers to a systematic process of checking the quality of a product based on a specified set of standards. In this procedure, the inspector examines a product sample in terms of its appearance, construction, function, and other conditions to see if they meet the specified requirements.
Installation drawing – Installation drawing is the drawing which is based on the detailed design or coordination drawing with the primary purpose of defining that information needed for the installation of plant and equipment. This drawing is particularly important for complex installations. The drawing comprises plan, section and elevation. Installation drawing includes information about (i) precise positioning, (ii) supports and fixings, (iii) information from manufacturers shop drawings, (iv) space allowances for installation, (v) installation work in connection, such as cutting, and, sealing holes, chasing block and brickwork for conduits or pipes, lifting and replacing floors, constructing plinths and so on, (vi) plant and equipment requirement, (vii) requirements for service connections, (viii) requirement to leave access space for operation and maintenance, and (ix) other maintenance access requirements such as access panels, decking, platforms, ladders and handrails. It is important that the information presented is carefully co-ordinated so that clashes are avoided.
Installed diaphragm pressure range – It is the high and low values of pressure applied to the diaphragm to produce rated travel with stated conditions in the valve body. It is because of the forces acting on the closure member which the inherent diaphragm pressure range can differ from the installed diaphragm pressure range.
Installed flow characteristic – It is the relationship between the flow rate and the closure member travel as it is moved from the closed position to rated travel as the pressure drop across the valve is influenced by the varying process conditions.
Instantaneous erosion rate – It is the slope of a tangent to the cumulative erosion-time curve at a specified point on that curve.
Instantaneous recovery – It is the decrease in strain in a solid during the removal of force before any creep recovery takes place. It is normally determined at constant temperature. It is sometimes referred to as instantaneous recovery.
Instantaneous strain – It is the strain in a sample immediately upon achieving the given loading conditions in a creep test (before creep occurs). It is sometimes referred to as instantaneous strain.
Instantaneous stress – It is the stress which is produced by strain in a sample immediately on achieving the given constant-strain conditions in a stress-relaxation test before stress-relaxation occurs. It is sometimes referred to as instantaneous stress.
Instruction manual – It is meant to be a comprehensive resource for knowing about a given equipment, product, or system. The main purpose of the document is to make clear to user how to assemble / use / operate the equipment, product, or system it to its maximum potential. Instruction manuals provide detailed guidance. They are frequently provided by manufacturers and are essential tools for users to understand the use of equipment, product, or system effectively and safely.
Instrument analysis – It consists of the methods of chemical analysis with the help of different types of instruments. These methods are widely used for the qualitative and quantitative elemental analysis of raw materials, iron (hot metal), steel, slag, refractories, and sludges samples. Compared to the wet analysis, the advantage of instrument analysis is that it is cost effective and multi elemental besides being very fast. The worries caused by interfering elements in the wet chemical analysis are eliminated. Instrument analysis avoids the need of waiting several hours for certain elements, which is a necessity when the wet chemical methods are employed. Furthermore, instrument analysis provides a fairly uniform detection limit across a large list of elements or compounds and is applicable to a wide range of concentrations, ranging from 100 % to few parts per million (ppm). The instrumental methods are reproducible with lesser scope of human error because of lesser human intervention. They are rugged, reliable and accurate with the accuracy depends upon the calibration and the standards used for the calibration.
Instrumentation – It is a collective term for measuring instruments which are used for indicating, measuring, and recording physical quantities. It is a device which turns some physical property into a measurement.
Instrumentation diagrams – These are the descriptive diagrams made following standardized methods and rules. However, the scope of instrumentation is so wide that a single form of diagram is not sufficient to capture all what is required to be represented. The different types of instrumentation diagrams which are commonly used are (i) process flow diagram (PFD), (ii) loop diagrams (loop sheets), (iii) process and instrument diagrams (P&ID), and (iv) functional diagrams.
Instrumentation engineering – It is the discipline dealing with development of measuring systems.
Instrumented Charpy impact test – The use of additional instrumentation (typically an instrumented tup) allows a standard Charpy impact testing equipment to monitor the analog load-time response of Charpy V-notch sample deformation and fracturing. The primary advantage of instrumenting the Charpy test is the additional information obtained while maintaining low cost, small samples, and simple operation. The normal used approach is the application of strain gauges to the striker to sense the load-time behaviour of the test sample. In some cases, gauges are placed on the sample as well. Instrumentation of the tup provides valuable data in terms of the load-time and the history during impact.
Instrumented impact test – It is an impact test in which the load on the sample is continually recorded as a function of time and / or sample deflection prior to the fracture.
Instrument identification tags – Instrumentation diagrams, reference is made to different instruments by lettered identifiers such as TT (temperature transmitter), PDT (pressure differential transmitter), or FV (flow valve) etc., without formally defining all the letters. Each instrument within an instrumented facility normally has its own unique identifying tag consisting of a series of letters describing the instrument’s function, as well as a number identifying the particular loop it belongs to. An optional numerical prefix typically designates the larger area of the facility in which the loop resides, and an optional alphabetical suffix designates multiple instances of instruments within one loop. As an example, if an instrument bearing the tag FC-135 means that it is a flow controller (FC) for loop number 135. In a large manufacturing facility with multiple processing ‘unit’ areas, a tag such as this can be preceded by another number designating the unit area. As an example, the hypothetical flow controller might be labeled 12-FC-135 means flow controller for loop number 135, located in unit number 12. If this loop happened to contain multiple controllers, then there is a need to distinguish them from each other by the use of suffix letters appended to the loop number (e.g. 12-FC-135A, 12-FC-135B, and 12-FC-135C etc.).
Instrument response time – It is the time needed for an indicating or detecting device to attain a defined percentage of its steady-state value following an abrupt change in the quantity being measured.
Insulated gate bipolar transistor (IGBT) – It is a power semi-conductor device which combines some of the advantages of field-effect and bipolar transistors. It is a three-terminal power semiconductor device primarily forming an electronic switch. It has been developed to combine high efficiency with fast switching. It consists of four alternating layers (NPNP) which are controlled by a metal-oxide semi-conductor (MOS) gate structure. Although the structure of the insulated gate bipolar transistor is topologically similar to a thyristor with a ‘metal-oxide semi-conductor gate’ (MOS-gate thyristor), the thyristor action is completely suppressed, and only the transistor action is permitted in the entire device operation range. It is used in switching power supplies in high-power applications.
Insulating materials, thermal – These are the materials or material complexes apparently resistant to thermal currents. These materials are used for thermal preservation and heat insulation.
Insulating pads and sleeves – Insulating material, such as gypsum, diatomaceous earth, and so forth, used to lower the rate of solidification. As sleeves on open risers, they are used to keep the metal liquid, hence increasing the feeding efficiency.
Insulating refractories – The function of insulating refractories is to reduce the rate of heat flow (heat loss) through the walls of furnaces. The desirable feature of insulating refractories is the low thermal conductivity, which usually results from a high degree of porosity. Structure of air insulating material consists of minute pores filled with air which have in them very low thermal conductivity. The air spaces inside the brick prevent the heat from being conducted but the solid particles of which the brick is made conduct the heat. So, in order to have required insulation property in a brick a balance has to be struck between the proportion of its solid particles and air spaces. The thermal conductivity is lower if the volume of air space is larger. Importantly, the thermal conductivity of a brick does not so much depend on the size of pores as on the uniformity of size and even distribution of these pores. Hence, uniformly small sized pores distributed evenly in the whole body of the insulating brick are preferred.
Insulating refractory brick (IRB) – It is the term used for heat insulating bricks and it covers those heat insulating materials which are applied up to 1,000 deg C. Insulating refractory bricks are frequently mistakenly referred to as rear insulation materials. These bricks are assigned to the group of light-weight refractory bricks and are manufactured on the basis of naturally occurring light-weight raw materials. Insulating refractory brick is a class of brick, which consists of highly porous fireclay or kaolin. Insulating refractory bricks are light-weight, low in thermal conductivity, and yet sufficiently resistant to temperature to be used successfully on the hot side of the furnace wall, hence permitting thin walls of low thermal conductivity and low heat content. The low heat content is particularly important in saving fuel and time on heating up, allows rapid changes in temperature to be made, and permits rapid cooling. Insulating refractory brick is characterized by the presence of large quantity of porosity in it. The pores are mostly closed pores. The presence of porosity decreases the thermal conductivity of the insulating bricks.
Insulating refractory materials – These materials can be classified into four types with respect to application temperature. These four types are (i) heat resistant insulating materials for application temperatures up to 1,100 deg C (examples are calcium silicate materials, products from siliceous earth, perlite or vermiculite, silica based micro porous heat insulators, and alumino-silicate fibres), (ii) refractory insulating materials for application temperatures up to 1,400 deg C (examples are lightweight chamotte and kaolin bricks, lightweight castables, and mixed and aluminum oxide fibres), (iii) high refractory insulating materials for application temperatures up to 1,700 deg C (examples are lightweight mullite and alumina bricks, lightweight hollow sphere corundum castables and bricks, and special high refractory fibres) and (iv) ultra-high refractory insulating materials for application temperatures up to 2,000 deg C (examples are zirconia lightweight bricks and fibers, and non-oxide compounds). Several other types of insulating refractory materials include castables, granular insulation, and ceramic fibre insulation, which is light weight. Extremely lightweight materials have a porosity of 75 % to 85 % and ultra-lightweight, high-temperature insulating materials have a total porosity higher than 85 %.
Insulation – It is a material of low thermal conductivity used to reduce heat losses.
Insulation material, electrical – Insulation material means a material having good dielectric properties, which is used to separate or isolate the conducting electrical parts. Insulation to be used for cables is required to have several properties namely (i) it is to have a high specific resistance and dielectric strength; (ii) it is to be tough and flexible, (iii) it is not to be hygroscopic i.e. it does not absorb moisture from air or surroundings, (iv) it is to be capable of standing high temperatures without much deterioration, (v) it is to be non-inflammable and fire retardant, (vi) it does not be attacked by acids or alkalis, and (vi) it is to be capable of withstanding high rupturing voltages. Electrical insulation materials are utilized to provide electrical isolation over the metallic conductors of underground cables. The insulating materials physically protect the conductor and provide a margin of safety. The common insulating material is poly vinyl chloride (PVC) compound which is applied to the conductors by the extrusion process. It is so applied that it can be removed without damaging the conductor.
Insulation monitoring device – It is a supervisory device to detect failure of electrical insulation.
Insulation resistance – It is the electrical resistance between two conductors or systems of conductors separated only by insulating material. It is also the ratio of the applied voltage to the total current between two electrodes in contact with a specified insulator. It is also the electrical resistance of an insulating material to a direct voltage.
Insulation screening – Cables rated for 6.35 kilovolts / 11 kilovolts are provided with insulation screening. It consists of two parts, namely non-metallic (semi-conducting) and metallic.
Insulation, thermal – It is the reduction of heat transfer (i.e., the transfer of thermal energy between objects of differing temperature) between objects in thermal contact or in range of radiative influence. Thermal insulation can be achieved with specially engineered methods or processes, as well as with suitable object shapes and materials.
Insulator – It is a substance which does not permit easy flow of electric current. It is a fitting intended to support a conductor. It is a material of such low electrical conductivity that the flow of current through it can normally be neglected. Similarly, it is a material of low thermal conductivity, such as which is used to insulate structural shells.
Insulators, transmission line – These insulators are devices used to contain, separate, or support electrical conductors on high voltage electricity supply networks. Transmission insulators come in various shapes and types, including individual or strings of disks, line posts or long rods. They are made of polymers, glass and porcelain, each with different densities, tensile strengths and performing properties in adverse conditions. Types of insulators include (i) pin type, (ii) suspension type, (iii) strain insulator, and (iv) shackle insulator.
Insurance spare – An insurance spare is a spare part whose impact of not holding the spare part in stores can be massive. Downtime costs of the equipment for such spares frequently far outweigh all the other costs. Hence, by definition, it is an insurance against such failures for which the down time costs are very high. They do not become obsolete until the parent equipment remains under use. These spare parts may lie in the stores for many years. These spares need conservation activities at regular intervals. These spares block the working capital.
Integral blower – It is a blower built as an integral part of a device to supply air thereto.
Integral blower burner – It is a burner of which the blower is an integral part.
Integral composite structure – It is the composite structure in which several structural elements, which are conventionally assembled together by bonding or mechanical fasteners after separate fabrication, are instead laid up and cured as a single, complex, continuous structure, e.g., spars, ribs, and one stiffened cover of a wing box fabricated as a single integral part. The term is sometimes applied more loosely to any composite structure not assembled by mechanical fasteners. All or some parts of the assembly can be co-cured.
Integrally heated – It is a term referring to tooling which is self-heating, through use of electrical heaters such as cal rods. Majority of the hydroclave tooling is integrally heated. Some autoclave tooling is integrally heated to compensate for thick sections, to provide high heat-up rates, or to permit processing at a higher temperature than is otherwise possible with the autoclave.
Integral skin foam – It is urethane foam with a cellular core structure and a relatively non-porous skin.
Integrated circuit – It is also known as a micro-chip, computer chip, or simply chip. It is a small electronic device made up of multiple interconnected electronic components such as transistors, resistors, and capacitors. These components are etched onto a small piece of semiconductor material, normally silicon. Integrated circuits are used in a wide range of electronic devices to perform different functions such as processing and storing information. They have greatly impacted the field of electronics by enabling device miniaturization and improved functionality.
Integrated gate-commutated thyristor (IGCT) – It is a power semi-conductor electronic device which is used for switching electric current in industrial equipment. It is related to the gate turn-off (GTO) thyristor. Like the gate turn-off thyristor, the integrated gate-commutated thyristor is a fully controllable power switch, meaning that it can be turned both on and off by its control terminal (the gate). Gate drive electronics are integrated with the thyristor device. An integrated gate-commutated thyristor is a special type of thyristor. It is made of the integration of the gate unit with the gate-commutated thyristor wafer device. The close integration of the gate unit with the wafer device ensures fast commutation of the conduction current from the cathode to the gate.
integrated product development team (IPDT) – It is a flexible, collaborative, multi-disciplinary team assigned with the responsibility of developing a product and the process to manufacture it. In addition to design and manufacturing engineers with the appropriate technical backgrounds, the team is to include members with operational, quality control, financial, marketing, field service, and purchasing experience.
Integrated waste strategy (IWS) – It describes how a plant site optimizes its approach to waste management. It includes the waste streams and discharges expected from present and future operations at the site, and the actions needed to improve the site’s approach to waste management.
Integration principle – This principle states that all other things being equal, a good layout is one which integrates 4Ms i.e., men, materials, machines, and methods in the best possible manner.
Integration – A layout is required to have a close integration of men, materials and equipment and support services in order to get the optimum output of the resources.
Intellectual property – It is the knowledge-based property, normally represented by patents, copyrights, trademarks, or trade secrets.
Intelligent control – It is the application of artificial intelligence techniques to process control.
Intelligent pump – It is a pump which has the ability to regulate and control flow or pressure. Typical advantages are energy savings, lifetime improvements, and system cost reductions.
Intense quenching – It is the quenching in which the quenching medium is cooling the part at a rate at least two and a half times faster than still water.
Intensiostatic – It is an experimental technique whereby an electrode is maintained at a constant current in an electrolyte.
Intensity (X-rays) – It is the energy per unit of time of a beam per unit area perpendicular to the direction of propagation.
Intensity of scattering – It is the energy per unit time per unit area of the general radiation diffracted by matter. Its value depends on the scattering power of the individual atoms of the material, the scattering angle, and the wave-length of the radiation.
Intensity ratio – It is the ratio of two (relative) intensities.
Intercept method – It is a quantitative metallographic technique in which the desired quantity, such as grain size or inclusion content, is expressed as the number of times per unit length a straight line on a metallographic image crosses particles of the feature being measured.
Interchangeability – Interchangeability is the suitability for a process, product or service to be used in place of another to fulfill a relevant requirement. Interchangeability can be introduced through an intentional standardization process. Process of standardization assists in the interchangeability even if the processes, products or services are created in different countries.
Interconnected pore volume – It is the volume fraction of pores which are interconnected within the entire pore system of a compact or sintered product.
Interconnected porosity – It is a network of connecting pores in a sintered object which permits a fluid or gas to pass through the object. It is also referred to as interlocking or open porosity.
Inter-critical annealing – It is an annealing treatment which involves heating to, and holding at, a temperature between the upper and lower critical temperatures to get partial austenitization, followed by either slow cooling or holding at a temperature below the lower critical temperature.
Inter-critical heat-affected zone (ICHAZ) – It experiences a peak temperature between Ac1 temperature and Ac3 temperature, and has a mixed structure of fine re-austenitized grains and tempered martensite retained from the base metal.
Inter-crystalline – It means between the crystals, or grains, of a poly-crystalline material.
Inter-crystalline (inter-granular) corrosion – Inter-crystalline corrosion is a special form of localized corrosion, where the corrosive attack takes place in a quite narrow path preferentially along the grain boundaries in the metal structure. The most common effect of this form of corrosion is a rapid mechanical disintegration (loss of ductility) of the material. Normally, it can be prevented by using the right material and production process. A well-known example relevant to the construction industry is the so-called sensitization of stainless steel. When certain grades of stainless steel are kept at a temperature within the range of 500 deg C to 800 deg C for a considerable time, e.g., during a welding process, chromium-rich carbides are formed, resulting in chromium depletion at the grain boundaries. Consequently, the grain boundaries possess a lower degree of corrosion resistance than the residual material, leading to localized corrosion.
Inter-crystalline cracking – It is the cracking or fracturing which occurs between the grains or crystals in a polycrystalline aggregate. It is also called inter-granular cracking.
Inter-crystalline cracks – These are the cracks or fractures which occur between the grains or crystals in a polycrystalline aggregate.
Inter-dendritic corrosion – It is the corrosive attack that progresses preferentially along inter-dendritic paths. This type of attack results from local differences in composition, such as coring normally encountered in alloy castings.
Inter-dendritic -It means located within the branches of a dendrite or between the boundaries of two or more dendrites.
Inter-dendritic porosity – It is the voids occurring between the dendrites in cast metal.
Interface – It is a surface which forms the boundary between any two phases. Among the three phases (gas, liquid, and solid), there are five types of interfaces namely gas-liquid, gas-solid, liquid-liquid, liquid-solid, and solid-solid. It is the boundary or surface between two different, physically distinguishable media. On fibres, it is the contact area between fibres and sizing or finish. In a laminate, it is the contact area between the reinforcement and the laminating resin.
Interface activity – It is a measure of the chemical potential between the contacting surfaces of two particles in a compact or two grains in a sintered body.
Interface control drawing – It depicts physical and functional interfaces of related or co-functioning items. It does not establish item identification. This drawing controls one or more of the interfaces such as mechanical, electrical, interconnections, configuration, installation, operational sequence requirements, and system switching etc. The drawing includes (i) configuration and interface dimensional data applicable to the envelope, mounting, and interconnection of the related items, (ii) complete interface engineering requirements (mechanical, electrical, electronic, hydraulic, and pneumatic etc.) which affect the physical or functional characteristics of the co-functioning items, and (iii) any other characteristics which cannot be changed without affecting system interfaces.
Interfacial tension – It is the contractile force of an interface between two phases.
Interference – It is the effect of a combination of wave trains of different phases and amplitudes.
Interference filter – It is a combination of several thin optical films to form a layered coating for transmitting or reflecting a narrow band of wave-lengths by interference effects.
Interference fits – It is a joint or mating of two parts in which the male part has an external dimension larger than the internal dimension of the mating female part. Distension of the female by the male creates a stress, which supplies the bonding force for the joint.
Interference of waves – It is the process whereby two or more waves of the same frequency or wave-length combine to form a wave whose amplitude is the sum of the amplitudes of the interfering waves.
Interferometer – It is an instrument in which the light from a source is split into two or more beams, which are subsequently reunited and interfere after traveling over different paths.
Intergranular – It means between the grains or crystals. It is also called intercrystalline.
Intergranular attack – it is also known as intergranular corrosion. It is a form of corrosion where the boundaries of crystallites of the material are more susceptible to corrosion than their insides.
Intergranular beta – It is the beta phase situated between alpha grains. It can be at grain corners, as in the case of equiaxed alpha-type micro-structures in alloys having low beta-stabilizers contents.
Intergranular corrosion – It is the corrosion occurring preferentially at grain boundaries, normally with slight or negligible attack on the adjacent grains.
Intergranular cracking – It is the cracking or fracturing which occurs between the grains or crystals in a polycrystalline aggregate. It is also called intercrystalline cracking.
Intergranular fracture – It is the brittle fracture of a polycrystalline material in which the fracture is between the grains, or crystals, which form the material. It is also called intercrystalline fracture.
Intergranular penetration – In welding, it is the penetration of a filler metal along the grain boundaries of a base metal.
Intergranular stress-corrosion cracking (IGSCC) – It is the stress-corrosion cracking in which the cracking occurs along grain boundaries.
Integrated blade inspection system – It is the quantitative assessment of process performance capabilities and process characterization is absolutely necessary in implementing automated non-destructive examination systems. At a gas turbine overhaul facility, e.g., quantitative assessment methods have been applied to the implementation of an integrated blade inspection system with an automated fluorescent penetrant inspection module. The processed blades are introduced into a robotic
handling system which manipulates the blade in a high-gain optical-laser scan readout system to produce a digitized image of the fluorescent penetrant indications. A computerized data processing and image analysis system provides the readout and decision processing to accept or reject the blades.
Interim spent fuel store – It is a store where spent fuel cools until it is suitable for disposal or where such fuel is stored pending disposal.
Inter-laboratory standard – It is a device which travels between the laboratories for the sole purpose of relating the magnitude of the physical unit represented by the standards maintained in the respective laboratories.
Interlaminar– It is the descriptive term pertaining to an object (e.g., voids), event (e.g., fracture), or potential field (e.g., shear stress) referenced as existing or occurring between two or more adjacent laminae.
Interlaminar fracture toughness (IFT) – It is a measure of the ability of a material to resist delamination.
Interlaminar shear – It is the shearing force tending to produce a relative displacement between two laminae in a laminate along the plane of their interface.
Interleaving – It is the insertion of paper or application of suitable strippable coatings between layers of metal to protect from damage.
Inter-lock – It is a device provided to ensure that an event does not occur inadvertently or that a specific sequence of events is followed where the sequence is important or necessary and a wrong sequence of
events can cause a mishap. It is a device to prove the physical state of a needed condition, and to furnish that proof to the primary safety control circuit.
Intermediate annealing – It is the annealing of the wrought metals at one or more stages during manufacture and before final treatment.
Intermediate cooler – Intermediate cooler functions as a tuyere cooler. It is situated between the breast cooler and the tuyere. It is the water-cooled copper device in which the tuyeres become fixed in the furnace housing. It helps to make the heat exchange of the tuyere, taking away heat and preventing its passage into the surroundings of the blast furnace.
Intermediate electrode – It is an electrode in an electrolytic 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.
Intermediate frequency – In communications and electronic engineering, an intermediate frequency is a frequency to which a carrier wave is shifted as an intermediate step in transmission or reception.
Intermediate level waste (ILW) – It is the waste with radioactivity levels exceeding the upper boundaries for ‘low level waste’ (LLW), but which do not need temperature to be taken into account in the design of storage or disposal facilities. Intermediate level waste arises mainly from the reprocessing of spent fuel, and from general operations and maintenance of radioactive plant. The main components of the intermediate level waste are metals, sludges, and organic materials, with smaller quantities of cement, graphite, glass, and ceramics.
Intermediate phase – In an alloy or a chemical system, it is a distinguishable homogeneous phase whose composition range does not extend to any of the pure components of the system.
Intermediate rock – It is an igneous rock which contains 52 % to 66 % quartz.
Intermediate temperature setting adhesive – It is an adhesive which sets in the temperature range from 30 deg C to 100 deg C.
Intermetallic compound – It is an intermediate phase in an alloy system, having a narrow range of homogeneity and relatively simple stoichiometric proportions. The nature of the atomic binding can be of different types, ranging from metallic to ionic.
Intermetallic phases – These are compounds, or intermediate solid solutions, containing two or more metals, which normally have compositions, characteristic properties, and crystal structures different from those of the pure components of the system.
Intermetallics – These are interior layers of the galvanized coating which have distinct proportions of the alloying metals iron and zinc, examples are delta, gamma and zeta layers.
Intermittent blow-down – It is the blowing down of boiler water at intervals.
Intermittent energy source – It is an energy source whose availability is not under human control. It can be sporadically available or available on some natural schedule not coincident with human demands. These are the energy sources which are not dispatchable.
Intermittent weld – It is a weld in which the continuity is broken by recurring unwelded spaces.
Internal friction – It is the conversion of energy into heat by a material subjected to fluctuating stress.
Internal grinding – It consists of grinding an inside of a rotating work-piece by use of a wheel spindle which rotates and reciprocates through the length or depth of the hole being ground.
Internal oxidation – It consists of isolated corrosion beneath the metal surface. This occurs as the result of preferential oxidation of certain alloy constituents by inward diffusion of oxygen, nitrogen, sulphur, and so on. It is also known as sub-surface corrosion. It is also preferential in situ oxidation of certain components of phases within the bulk of a solid alloy accomplished by diffusion of oxygen into the body. This is normally used to prepare electrical contact materials.
Interpenetrating polymer network – It consists of a combination of two polymers in a network in which at least one (or both) is crosslinked around the other. Interpenetrating polymer networks are frequently used to toughen epoxy matrices, where the epoxy is continuous and a thermoplastic polymer is discontinuous.
Internal shrinkage – It is a void or network of voids within a casting caused by inadequate feeding of that section during solidification.
Internal standard – In spectroscopy, it is a material present in or added to samples which serves as an intensity reference for measurements. It is used to compensate for variations in sample excitation and photographic processing in emission spectroscopy.
Internal standard line – In spectroscopy, it is a spectral line of an internal standard, with which the radiant energy of an analytical line is compared.
Internal stress – It is the stress present in a body which is free of external forces or thermal gradients.
Interphase – It is the boundary region between a bulk resin or polymer and an adherend in which the polymer has a high degree of orientation to the adherend on a molecular basis. It plays a major role in the load transfer process between the bulk of the adhesive and the adherend or the fibre and the laminate matrix resin.
Interply cracks – These are through-cracking of individual layers within a composite lay-up, perpendicular to the ply interfaces.
Interply hybrid – It is a composite in which adjacent laminae are composed of different materials.
Inter-system crossing – It is a transition between electronic states which differ in total spin quantum number.
Internal validity – It is the extent to which treatment-group differences on a study endpoint represent the causal effect of the treatment on the study endpoint.
Internal latent heat, true (internal energy of steam) – It is the energy needed to change the phase. Hence, it is the actual heat energy stored in the steam above 0 deg C. It can be calculated by subtracting the external work of evaporation from the enthalpy. Its unit is kilojoule per kilogram.
Internal oxidation – It is the formation of isolated particles of corrosion products beneath the metal surface. This occurs as the result of preferential oxidation of certain alloy constituents by inward diffusion of oxygen, nitrogen, sulphur, and so forth. Though internal oxidation which is formation of relatively fine sub-surface oxide inclusions, is mainly talked about in steel. Similar phenomena have also been reported in silver-aluminum, copper-aluminum and silver- indium alloys. Such mechanism has also been attributed to the formation of nitrogen, sulphur, selenium and tellurium bearing internal inclusions. The mechanism and kinetics of internal oxidation is fairly well studied. The stability of internally oxidized zone can best be described in terms of relative fluxes of oxygen and metal and the number of oxygen atoms per metal atom of the oxide compound. Normally the internal oxidation is harmful and can be classified as a surface / subsurface defect strongly affecting the property.
Internal pressure, gasket – It is the forces which are continually trying to unseal a gasketed joint by exerting pressure against the gasket (blow-out pressure) and against the flanges holding the gasket in place (hydrostatic end force).
Internal (ring) gears – Internal gears produce an output rotation that is in the same direction as the input, As the name implies, teeth are cut on the inside surface of a cylindrical ring, inside of which are mounted either a single external tooth spur gear or a set of external tooth spur gears, typically consisting of three or four larger spur gears (planets) usually surrounding a smaller central pinion (sun). Normally, the ring gear is stationary, causing the planets to orbit the sun in the same rotational direction as that of the sun. For this reason, this class of gear is often referred to as a planetary system. The orbiting motion of the planets is transmitted to the output shaft by a planet carrier. In an alternative planetary arrangement, the planets may be restrained from orbiting the sun and the ring left free to move. This causes the ring gear to rotate in a direction opposite that of the sun. By allowing both the planet carrier and the ring gear to rotate, a differential gear drive is produced, the output speed of one shaft being dependent on the other.
Internal shrinkage – It consists of a void or network of voids within a casting caused by inadequate feeding of that section during solidification.
Internal stress – It is the stress which is not depending on external forces resulting from such factors as cold working, phase changes, or temperature gradients. It is also known as residual stress. It is the stress present in a steel member or fabrication which is free of external forces or thermal gradients.
Internal treatment – The internal treatment for softening of water is also known as conditioning of water. In the internal treatment, the softening of water is carried out in the water-cooling circuit. In this method, some types of chemicals are added to hard water to remove the negative effect of calcium and magnesium. Chemical treatment for softening results into low levels of hardness of water. For purifying hard water from a single source, it is economically feasible method. Selection of the proper chemical is determined by the raw water composition and the desired quality after softening. In case several chemicals are applicable, aspects of operational management also become important. During the internal treatment for softening of water, the hardness causing salts are removed (i) by complexing the hardness causing salts to soluble salts by adding suitable reagents, (ii) by precipitating the scale forming impurities in the form of sludge which can be removed by blow down operation, and (iii) by converting the scale forming salts into other compounds which stay in ‘dissolved form’ and do not cause any trouble to the cooling elements, pipelines, and fittings of the cooling system. The important internal conditioning methods are (i) colloidal conditioning, (ii) phosphate conditioning, (iii) carbonate conditioning, (iv) Calgon conditioning, and (v) conditioning with sodium aluminate.
Internally-fired boiler – Internally-fired boiler has the combustion chamber located within the shell of the boiler, or the furnace is surrounded by water-tubes.
Internal venting – These are holes on the inside of enclosed fabrications which allow cleaning solutions, zinc, and any gases to freely flow throughout the structure.
International Electrotechnical Commission (IEC) – It is an international standards organization devoted to electrical standards. Majority of the countries are its members.
International measurement standard – It is a standard recognized by an international agreement to serve internationally as the basis for assigning values to other standards of the quantity concerned.
International nuclear events scale (INES) – It is a scale from 1 to 7 introduced by the International Atomic Energy Agency (IAEA) in 1990 to assess and classify the impact(s) of nuclear accidents, where 1 is an anomaly and 7 is a major accident.
International Organization for Standardization – It is an international organization coordinating the efforts of national technical standards organizations. It develops and publishes international standards in technical and nontechnical fields, including everything from manufactured products and technology to food safety, transport, information technology (IT), agriculture, and healthcare.
International practical temperature scale – It is based on six reproducible temperatures (defining fixed points), to which numerical values are assigned, and on formulas establishing the relation between temperature and the indications of instruments calibrated by means of values assigned to the six defining fixed points. These fixed points are defined by specified equilibrium states, each of which, except for the triple point of water, is under a pressure of 101,325 newtons per square meters (1 standard atmosphere).
International system of units – It is internationally known by the abbreviation ‘SI’, is the modern form of the metric system. It is widely used system of measurement and is the only system of measurement used in science, technology, industry, and everyday commerce. The ‘SI’ comprises a coherent system of units of measurement starting with seven base units, which are the second (symbol ‘s’, the unit of time), metre (‘m’, length), kilogram (‘kg’, mass), ampere (‘A’, electric current), kelvin (‘K’, thermodynamic temperature), mole (‘mol’, quantity of substance), and candela (‘cd’, luminous intensity). The system can accommodate coherent units for an unlimited number of additional quantities. These are called coherent derived units, which can always be represented as products of powers of the base units. Twenty-two coherent derived units have been provided with special names and symbols.
International temperature scale of 1990 (ITS-90) – It is an equipment calibration standard specified by the International Committee of Weights and Measures (CIPM) for making measurements on the Kelvin and Celsius temperature scales. It is an approximation of thermodynamic temperature that facilitates the comparability and compatibility of temperature measurements internationally. It defines fourteen calibration points ranging from 0.65 Kelvin to 1,357.77 Kelvin (−272.50 deg C to 1,084.62 deg C) and is subdivided into multiple temperature ranges which overlap in some instances.
Interoperability – It refers to the degree to which a software system, devices, applications or other entity can connect and communicate with other entities in a coordinated manner without effort from the end user. Examples are nuts and bolts, screw threads, railway gauges, electrical plugs and outlets etc.
Interpass temperature – In a multiple-pass weld, it is the temperature (minimum or maximum as specified) of the deposited weld metal before the next pass is started.
Interplanar distance – It is the perpendicular distance between adjacent parallel lattice planes.
Inter-quartile range (IQR) – The interquartile range is the difference between the upper and lower quartiles. If the lower and upper quartiles are denoted by Q1 and Q3, respectively, the interquartile range is (Q3 – Q1). The phrase ‘inter-quartile range’ was first used by Galton in 1882.
Interrupted aging – It is the aging at two or more temperatures, by steps, and cooling to room temperature after each step.
Interrupted-current plating – It is the plating in which the flow of current is discontinued for periodic short intervals to decrease anode polarization and elevate the critical current density. It is very frequently used in cyanide copper plating.
Interrupted quenching – It is a quenching procedure in which the work-piece is removed from the first quench at a temperature substantially higher than that of the quenchant and is then subjected to a second quenching system having a different cooling rate than the first.
Interrupter – It is any of a series of automatically operated electro-mechanical switches which periodically opened and closed a circuit.
Interstitial free (IF) steel – The term ‘Interstitial Free steel or IF steel’ refers to the fact, that there are no interstitial solute atoms to strain the solid iron lattice, resulting in very soft steel. IF steels have interstitial free body centered cubic (bcc) ferrite matrix. These steels normally have low yield strength, high plastic strain ratio (r-value), high strain rate sensitivity and good formability. Conventional interstitial free steels have been developed commercially following the introduction of vacuum degassing technology. These steels contain carbon in the range of 40 parts per million to 70 parts per million and nitrogen in the range of 30 parts per million to 50 parts per million. Later, niobium and / or titanium have been added to these steels to stabilize the interstitial carbon and nitrogen atoms. Interstitial free steel is a sheet steel product with very low carbon levels. Interstitial free steel is used mainly in automotive deep drawing applications. The improved ductility (drawing ability) of interstitial free steels is made possible by vacuum degassing.
Interstitial solid solution – It is a type of solid solution which sometimes forms in alloy systems having two elements of widely different atomic sizes. Elements of small atomic size, such as carbon, hydrogen, and nitrogen, frequently dissolve in solid metals to form this solid solution. The space lattice is similar to that of the pure metal, and the atoms of carbon, hydrogen, and nitrogen occupy the spaces or interstices between the metal atoms.
Interval erosion rate – It is the slope of a line connecting two specified points on the cumulative erosion-time curve.
Interval estimate – It is the estimate of a parameter given by two statistics, defining the end points of an interval.
Interval estimation – It is the use of sample data to estimate an interval of possible values of a parameter of interest. This is in contrast to point estimation, which gives a single value.
Interval test – It is the method used to test heat extraction rates of various quenchants. This test measures the increase in temperature of a quenchant when a standard bar of metal is quenched for five seconds. Faster quenchants show greater temperature increases.
Intracrystalline – It means within or across the crystals or grains of a metal. It is same as transcrystalline and transgranular.
Intracrystalline cracking – It is the cracking or fracturing which occurs through or across a crystal or grain. It is also called transcrystalline cracking.
Intralaminar – It is descriptive term pertaining to an object (e.g., voids), event (e.g., fracture), or potential field (e.g., temperature gradient) existing entirely within a single lamina without reference to any adjacent laminae.
Intraply hybrid – It is a composite in which different materials are used within a specific layer or band.
Intrinsic viscosity [η]- It is a measure of a solute’s contribution to the viscosity η of a solution. It a dimensionless number.
Intrusive – It is a body of igneous rock formed by the consolidation of magma intruded into other rocks, in contrast to lavas, which are extruded upon the surface.
Intumescence – It means the swelling or bubbling of a coating normally because of heating (term currently used in space and fire protection applications).
Invariant equilibrium – As per the phase rule, three phases can exist in stable equilibrium only at a single point on a urinary diagram. In an hypothetical urinary pressure-temperature diagram, the three states (or phases) i.e., solid liquid and gas are represented by three correspondingly fields. Stable equilibrium between two phases occurs along their mutual boundary, and invariant equilibrium among all three phases occurs at the so-called triple point where three boundaries intersect. This point is also called an invariant point because, at that location of the diagram, all externally controllable factors are fixed (no degree of freedom). At this point, all the three phases are in equilibrium, but any changes in pressure / temperature causes one or two of the states (phases) to disappear.
Inventory – In an organization there are stock of finished products, semi-finished products, in process materials raw materials, spare parts, operating parts, fuels, and consumables. The collective name of these entire items is inventory. The organization holds the inventory for the ultimate goal of sale, production, or utilization. Inventory management is a discipline primarily about specifying the shape and placement of stocked goods.
Inverse chill – It is the condition in a casting section in which the interior is mottled or white, while the other sections are gray iron. It is also known as reverse chill, internal chill, and inverted chill.
Inverse segregation – It is a concentration of low-melting constituents in those regions of an alloy in which solidification first occurs.
Inverted microscope – It is a microscope which is so arranged that the line of sight is directed upward through the objective to the object.
Inverter – It is a power electronic device or circuitry which changes direct current (DC) to alternating current (AC). The resulting alternating current frequency achieved depends on the particular device used. Inverters do the opposite of rectifiers. The input voltage, output voltage and frequency, and overall power handling depend on the design of the specific device or circuitry. The inverter does not produce any power; the power is provided by the direct current source. A power inverter can be entirely electronic or can be a combination of mechanical effects (such as a rotary apparatus) and electronic circuitry. Static inverters do not use moving parts in the conversion process.
Invert level – It is the base interior level of a pipe, trench or tunnel. It can be considered the ‘floor’ level. The invert is an important datum for determining the functioning or flowline of a piping system. Conversely, the obvert level is the highest interior level, and can be considered the ‘ceiling’ level, being the highest level.
Investing – In investment casting, it is the process of pouring the investment slurry into a flask surrounding the pattern to form the mould.
Investment – It is a flowable mixture, or slurry, of a graded refractory filler, a binder, and a liquid vehicle which, when poured around the patterns, conforms to their shape and subsequently sets hard to form the investment mould.
Investment casting – It is the casting metal into a mould produced by surrounding, or investing, an expendable pattern with a refractory slurry coating which sets at room temperature, after which the wax or plastic pattern is removed through the use of heat prior to filling the mould with liquid metal. It is also called precision casting or lost wax process. It is a part made by the investment casting process. In investment casting, a ceramic slurry is applied around a disposable pattern, normally wax, and allowed to harden to form a disposable casting mould. The term disposable means that the pattern is destroyed during its removal from the mould and that the mould is destroyed to recover the casting. There are two distinct processes for making investment casting moulds namely the solid investment (solid mould) process, and the ceramic shell process. The ceramic shell process has become the predominant technique for engineering applications, displacing the solid investment process. Today the solid investment process is primarily used to produce dental and jewelry castings and has only a small role in engineering applications, mostly for non-ferrous alloys. Investment casting can produce parts of similar geometric shapes and size. Since the disposable pattern is made by injecting wax into a mould, features which are difficult or costly to injection mould or die cast (e.g., undercuts) are also costly to investment casting. Investment casting is typically used when low production volumes are expected (e.g., less than 10,000 pieces).
Investment compound – It is a mixture of a graded refractory filler, a binder, and a liquid vehicle, which is used to make moulds for investment casting.
Investment moulding – It is the process which is also known as the lost wax process. Moulds are produced by dipping wax or thermoplastic patterns in a fine slurry to produce as smooth a surface as possible. The slurry is air dried and redipped several times using cheaper and coarser, more permeable refractory until the shell is of sufficient thickness for the strength needed to contain molten metal. Investment moulds also are produced as solid moulds by putting the pattern assembly in a flask, which is then filled with a refractory slurry and air dried. The moulds then are put into a furnace where the wax or plastic is melted and burned out of the mould cavity. Molten metal is poured into the moulds while the moulds are still superheated, hence making it possible to pour very thin wall sections. A metal pattern die is used to produce the wax or plastic expendable patterns. Investment moulding produces casting of superior surface finish, dimensional accuracy, and without parting fins or seams. This process is expensive and is used to produce parts which are very difficult or impossible to machine, such as turbine engine parts, particularly high-temperature, heat-resistant alloy applications such as turbine blades.
Investment precoat – It is an extremely fine investment coating applied as a thin slurry directly to the surface of the pattern to reproduce maximum surface smoothness. The coating is surrounded by coarser, cheaper, and more permeable investment to form the mould.
Investment shell – It is the ceramic mould got by alternately dipping a pattern set up in dip coat slurry and stuccoing with coarse ceramic particles until the shell of desired thickness is achieved.
In-wall batter – It is the negative slope of in-wall expressed numerically as the base of a right triangle whose altitude is 300 millimeters and whose hypotenuse is the slope of the in-wall.
Iodide – It consists of compounds with iodine in formal oxidation state -1. Iodide is one of the largest monatomic anions. Majority of the iodide salts are soluble in water, but frequently less so than the related chlorides and bromides. Iodide, being large, is less hydrophilic compared to the smaller anions.
Iodine number – Iodine number is the measure of the degree of the unsaturation of the lubricating oil. It is the amount of iodine, in grams, which is taken up by 100 grams of the oil. It determines the extent of contamination of oil. Each type of the lubricating oil has its specific iodine number. Low iodine number is desirable in oils.
Ion – It is an atom, or group of atoms, which by loss or gain of one or more electrons has acquired an electric charge. If the ion is formed from an atom of hydrogen or an atom of a metal, it is normally positively charged. If the ion is formed from an atom of a non-metal or from a group of atoms, it is normally negatively charged. The number of electronic charges carried by an ion is termed its electro-valence. The charges are denoted by superscripts which give their sign and number, e.g., a sodium ion, which carries one positive charge, is denoted by Na+; a sulphate ion, which carries two negative charges, by (SO4)2-.
Ion beam assisted deposition – It is an ion implantation technique in which ion beams are combined with physical vapour deposition.
Ion beam mixing – It is an ion implantation technique in which deposited layers (electroplating, sputtering) tens or hundreds of nanometers thick are mixed and bonded to the substrate by an argon or xenon ion beam.
Ion beam sputtering – It is an ion implantation technique in which an ion beam of argon or xenon directed at a target sputters material from the target to a substrate, the sputtered material arrives at the substrate with enough energy to promote good adhesion of the coating to substrate.
Ion carburizing – It is a method of surface hardening in which carbon ions are diffused into a work-piece in a vacuum through the use of high-voltage electrical energy. It is synonymous with plasma carburizing or glow discharge carburizing.
Ion chromatography – It is an area of high-performance liquid chromatography which uses ion exchange resins to separate various species of ions in solution and elute them to a suitable detector for analysis.
Ion etching – It is the surface removal by bombarding with accelerated ions in vacuum (1 kilovolt to 10 kilovolt).
Ion exchange – It is the reversible interchange of ions between a liquid and solid, with no substantial structural changes in the solid. It is also an exchange of ions in a crystal with irons in a solution. It is used as a method for recovering valuable metals, such as uranium, from solution.
Ion-exchange chromatography (IEC) – It is liquid chromatography with a stationary phase which possesses charged functional groups. This technique is applicable to the separation of ionic (charged) compounds.
Ion exchange demineralization – It is an application of ion exchange. Two main types of water treatment are exercised with the use of the ion exchange technology namely (i) water softening, and (ii) demineralization. Water softening is when minerals which give hardness to the water like calcium and magnesium are exchanged for sodium (which is a lighter molecule). Soft water is needed for several processes. Demineralization is when the ions in the solution are almost completely removed. This process is the basis on which the demineralization plant operates and produces demineralized water.
Ion exchange process – It uses resin beads with sodium (sometimes potassium) attached to them. An ion exchange occurs when hard water containing ions of calcium and / or magnesium flows through the resin beads. The resin beads release sodium ions to the water while capturing the calcium and / or magnesium ions. Once the resin is depleted, it is to be regenerated to flush out the captured hard water ions and replace them with a new source of sodium ions. This is done by using a salt solution (sodium chloride) from a brine tank. Once the regeneration process is complete, the system is rinsed to remove residual hard water ions and chloride ions from the salt, and the rinse water is sent to the drain. After being put back on-line, the newly soft water contains all the original substances which are in the incoming supply water minus the hard water ions which have been replaced with sodium ions. The process continues until the resin is again depleted of sodium, and regeneration of the resin beads is to be done. process occurs.
Ion exchange resin – It is a synthetic resin containing active groups (normally sulfonic, carboxylic, phenol, or substituted amino groups) which give the resin the property of combining with or exchanging ions between the resin and a solution. Ion exchange resins are insoluble, cross-linked, long chain organic polymers with a micro porous structure, and the ‘functional groups’ attached to the chains are responsible for the ion exchange properties. Resins containing acidic functional groups (-COOH, -SO3H) are capable of exchanging their H+ ions with other cations, which comes in their contact. Resins containing basic functional groups (amino groups) are capable of exchanging their anions with other anions, which comes in their contact. Ion-exchange resins can be classified as (i) cation exchange resins (R.H+), and anion exchange resins (R.OH-). Ion exchange resins are synthetic polymers which are insoluble in all solvents. They are capable of reacting like acids, bases, or salts. The resins, however, differ from acids, bases, and salts in one way. Only the cations (in cation exchange resins) or anions (in anion exchange resins) are free to take part in chemical reactions. Those exchange units in which the anionic portions are able to react are called anion exchange units whereas, the ones in which the cationic portions are able to react are called cation exchange units. In aqueous media and sometimes in non-aqueous media, cation exchange resins are able to exchange their cations with other cations and similarly anion exchange resins are able to exchange their anions with other anions.
Ionic bond – It is a type of chemical bonding in which one of more electrons are transferred completely from one atom to another, hence converting the neutral atoms into electrically charged ions. These ions are around spherical and attract each other because of their opposite charges. It is also a primary bond arising from the electrostatic attraction between two oppositely charged ions.
Ionic bonding – It is a type of chemical bonding which involves the electrostatic attraction between oppositely charged ions, or between two atoms with sharply different electro–negativities, and is the primary interaction occurring in ionic compounds. It is one of the main types of bonding, along with covalent bonding and metallic bonding. Ions are atoms (or groups of atoms) with an electrostatic charge. Atoms which gain electrons make negatively charged ions (called anions). Atoms which lose electrons make positively charged ions (called cations).
Ionic charge – It is the positive or negative charge of an ion.
Ion implantation – It is the process of modifying the physical or chemical properties of the near surface of a solid (target) by embedding appropriate atoms into it from a beam of ionized particles. The properties to be modified can be electrical, optical, or mechanical, and they can relate to the semi-conducting behaviour of the material or its corrosion behaviour. The solid can be crystalline, poly-crystalline, or amorphous and need not be homogeneous. Related techniques are also used in conjunction with ion implantation to increase the ratio of material introduced into the substrate per unit area, to provide appropriate mixtures of materials, or to overcome other difficulties involved in surface modification by ion implantation alone.
Ion nitriding – It is a method of surface hardening in which nitrogen ions are diffused into a work-piece in a vacuum through the use of high-voltage electrical energy. It is synonymous with plasma nitriding or glow discharge nitriding.
Ionization – It is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, frequently in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an ion. Ionization can occur because of high temperatures, electrical discharges, or nuclear radiations, It can also result from the loss of an electron after collisions with subatomic particles, collisions with other atoms, molecules, electron, positron, protons, antiprotons and ions, or through the interaction with electro-magnetic radiation.
Ionizing radiation – It is a radiation capable of displacing electrons from atoms or molecules, thereby producing ions. High doses of ionizing radiation can produce severe skin or tissue damage. Some examples are alpha, beta, gamma, X-rays, neutrons, and ultra-violet light.
Ion neutralization – It is the generic term for a class of charge-exchange processes in which an ion is neutralized by passage through a gas or by interaction with a material surface.
Ion-pair chromatography (IPC) – It is the liquid chromatography with a mobile phase containing an ion which combines with sample ions, creating neutral ion pairs. The ion pairs are typically separated using bonded-phase chromatography.
Ion plating – It is a generic term applied to atomistic film deposition processes in which the substrate surface and / or the depositing film is subjected to a flux of high-energy particles (normally gas ions) sufficient to cause changes in the interfacial region or film properties.
Ion-scattering spectrometry – It is a technique to elucidate composition and structure of the outermost atomic layers of a solid material, in which principally mono-energetic, singly charged, low-energy (less than 10 kilo-electron volt, keV) probe ions are scattered from the surface and are subsequently detected and recorded as a function of the energy.
Ion-scattering spectrum – It is a graph of scattered ion intensity as a function of the ratio of the scattered ion energy to the incident ion energy.
IRG transition diagram – Developed by the International Research Group (IRG) on Wear of Engineering Materials of the Organization of Economic Cooperation and Development (OECD), it is a graph of normal force in newtons (ordinate) against sliding velocity in meters per second (abscissa) wherein boundaries identify three distinct regions of varying lubricant effectiveness.
Ion species – It is a type and charge of an ion. If an isotope is used, it is to be specified.
Iron – Iron is a chemical element with symbol Fe (from Latin word Ferrum). Its atomic number is 26 and atomic mass is 55.845. It has a melting point of 1,538 deg C and boiling point of 2,862 deg C. The density of iron is 7.87 grams per cubic meter. It is a metal in the first transition series. Like the elements of other group 8 elements (ruthenium and osmium), iron exists in a wide range of oxidation states, +2 to +6, although +2 and +3 are the most common. Iron as a common metal is mostly confused with other metals such as different types of steels. Iron is by mass the most common element on the earth, forming much of earth’s outer and inner core. It is the fourth most common element and the second most common metal in the earth crust. Steels contain over 95 % Fe. Elemental iron occurs in meteoroids and other low oxygen environments, but is reactive to oxygen and water.
Iron alloy – It refers to a type of engineering material which is produced by combining iron with different alloying elements, such as carbon. These alloys have a wide range of micro-structures and properties, allowing them to be used in different applications.
Iron and steel scrap – It is also known as ‘ferrous metal scrap’ is a recyclable material which is left- over during the production of iron and steel products and fabrication of ferrous materials or generated at end of life of the ferrous products. Ferrous scrap is normally recycled during steelmaking. Amongst all kinds of ferrous scraps, steel scrap constitutes the maximum percentage. Ferrous metal scrap is the primary raw material for the production of liquid steel in the electric arc furnace and the induction furnace.
Iron carbide – It is a high melting point, non-pyrophoric, strongly magnetic synthetic compound got in granular or powder form. It is composed of three atoms of iron and one atom carbon and its chemical formula is Fe3C. The commercial iron carbide consists of around 90 % total iron and around 6 % to 6.5 % of total carbon. The primary use of the product is as a metallic charge during steelmaking for the substitution of hot metal, direct reduced iron, or steel scrap. Iron carbide is an inter-metallic compound of iron and carbon. It is, more precisely, intermediate transition metal carbide. Its stoichiometric composition consists of 6.67 % carbon and 93.3 % iron. It has an orthorhombic crystal structure). It is a hard, brittle material and normally classified as a ceramic in its pure form. It is a frequently found and important constituent in ferrous metallurgy. While iron carbide is present in majority of the steels and cast irons, it is produced as a raw material by the iron carbide process, which belongs to the family of alternative ironmaking technologies.
Iron-carbon phase diagram – It is a graphical representation of different phases of iron which exists within a given temperature, pressure, or weight percentage, It is an equilibrium diagram of iron and carbon. With its help, the relationship between the carbon content and the temperature is derived. On this basis, the phase composition can be determined. Carbon is the most important alloying element in iron. The iron-carbon phase diagram is widely used to understand the different phases of steel and cast iron.
Iron casting – It is a part made of cast iron.
Ironing – It is an operation which is used to increase the length of a tube or cup through reduction of wall thickness and outside diameter, the inner diameter remaining unchanged.
Iron loss – It is that portion of the wasted power of a machine or transformer which is attributed to hysteresis and eddy currents in the iron core.
Iron-making – It is the process of reduction of iron ore using the relevant reducing agent (reductant).
Iron notch – It is also known as tap hole. It is the opening in the furnace hearth for draining the hot metal as well as slag from the furnace. The iron notch is opened by drilling for tapping and after tapping closed with taphole mass by the mud gun.
Iron nuggets – These are pebble shaped with elliptical structure solid, high density, highly metalized iron produces from dry green balls using a direct reduction process. The reduction process is carried out in a rotary hearth furnace, using coal as the reductant and energy source. Iron nuggets are a premium grade iron product with superior shipping and handling characteristics. They can be stored outside with no special precautions. They can be handled as a bulk commodity using conventional magnets, conveyors, bucket loaders, clams, and shovels. They are having size in the range of 5 millimeters to 25 millimeters and a density in the range of 6.5 grams per cubic meters to 7 grams per cubic meters. The chemical composition of iron nuggets is metallic iron – 96 % to 97 %, carbon – 2 % to 3 %, and sulphur – 0.05 % to 0.07 %.
Iron ore – Iron ore is a type of mineral rock from which metallic iron is extracted economically. This ore is normally rich in iron oxides and vary in colour from dark grey, bright yellow and deep purple to rusty red. The mineral in the iron ore can vary depending on the deposit. Iron ore is capable of smelting iron under modern technological conditions and is economically cost-effective. Iron ore is composed of one or more iron containing minerals and gangues, which are also entrained with some impurities. The gangue is also composed of one or several minerals (compounds). Iron-bearing minerals and gangues are called minerals and are compounds with a certain chemical composition and crystal structure. The mineral in the iron ore can vary depending on the deposit. The minerals normally found in the iron ore are magnetite (Fe3O4), hematite (Fe2O3), goethite [FeO(OH)], limonite [FeO(OH).n(H2O)], or siderite (FeCO3).
Iron ore agglomeration technologies – These are the technologies for the agglomerating of iron ore fines. Five iron ore agglomeration technologies can be defined which are briquetting, nodulization, extrusion, pelletization, and sintering. Sintering and pelletization are the most important agglomeration technologies.
Iron ore pellet – It is a type of agglomerated iron ore fines which has better tumbler index when compared with that of the parent iron ore. Iron ore pellets are widely used as a substitute of lump ore for the production of direct reduced iron and in the blast furnace for the production of hot metal. The term iron ore pellet refers to the thermally agglomerated material formed by heating a variable mixture of iron ore, limestone, olivine, bentonite, dolomite, and miscellaneous iron bearing materials in the range of 1,250 deg C to 1,350 deg C. Iron ore pellets are normally produced in two types of grades namely direct reduced iron grade and blast furnace grade. The requirements of direct reduced iron grade pellets are (i) low quantity of silica and alumina (less than 0.9 %), (ii) high basicity, (iii) low reduction disintegration, (iv) low sticking tendency, and (v) high reducibility. The requirements of blast furnace grade pellets are (i) high and consistent quality, (ii) high productivity, (iii) low energy demand, (iii) additives to optimize blast furnace process performance and (iv) pellets to match high basicity sinter. Direct reduced iron grade pellets are also known as acid pellets while the blast furnace grade pellets are basic pellets. These pellets are fluxed pellets and have higher basicity than the direct reduced iron grade. Direct reduced iron grade pellets do not contain calcium oxide (CaO), while the blast furnace grade pellets are fluxing pellets containing calcium oxide. For the blast furnace grade pellets, reducibility and swelling index are important properties while for direct reduced iron grade disintegration is an important property.
Iron ore sinter – It is normally the major component of a blast furnace iron bearing burden material. Sinter normally consists of different mineral phases produced by sintering of iron ore fines with fluxes, metallurgical wastes and a solid fuel. Coke breeze is normally used as fuel in the sinter mix since it supplies necessary heat energy for sintering of sinter mix. A sinter is regarded as consisting of essentially three types of materials namely (i) original unaltered (primary) material, (ii) original secondary material which is the result of alteration of the structure and shape through recrystallization in the solid state, and (iii) secondary constituents which result from material that has fused or dissolved during sintering. These constituents can either mutually dissolved or can precipitate from the solution. Two types of bonding are theoretically possible depending on the mineralogical changes. These bonding are slag or fusion bond and diffusion bond.
Iron-hydrogen-oxygen system -It is the equilibrium diagram for iron (Fe) and iron oxides with a mixture of the gases hydrogen and steam (H2O).
Iron rot – It is the deterioration of wood in contact with iron-base alloys.
Iron soldering – It is a soldering process in which the heat needed is got from a soldering iron.
Irradiance (of a receiver) – It is the radiant power per unit area incident on a receiver.
Irradiation – It is the exposure of a material or object to X-rays, gamma rays, ultra-violet rays, or other ionizing radiation. This is the process by which an item is exposed to radiation.
Irregular powder – It is a powder having particles which lack symmetry.
Irreversible – It means not capable of redissolving or remelting. Chemical reactions which proceed in a single direction and are not capable of reversal (as applied to thermosetting resins).
Irritant – It is a substance which, in sufficient quantities, can inflame or irritate the eyes, other mucosa, skin or respiratory system (lungs, etc.). Symptoms include pain and reddening.
I-sections with narrow and medium flanges – These are ‘I’ sections in which the flange width is equal to or less than 0.66 × the nominal height of the section and less than 300 mm.
Isobar – In atomic physics, one of two or more atoms which have a common mass number ‘A’, but differ in atomic number ‘Z’. Hence, although isobars possess around equal masses, they differ in chemical properties, they are atoms of different elements.
Isocorrosion diagram – It is a graph or chart which shows constant corrosion behaviour with changing solution (environment) composition and temperature.
Isocratic elution – In liquid chromatography, it is the use of a mobile phase whose composition is unchanged throughout the course of the separation process.
Isocyanate plastics – These are the plastics based on resins made by the condensation of organic isocyanates with other compounds. These are normally reacted with polyols on a polyester or polyether backbone molecule, with the reactants being joined through the formation of the urethane linkage. See also polyurethane and urethane plastics.
Isolated-phase bus – It is a bus where each phase is in its own grounded metal enclosure to prevent faults from spreading from phase to phase. It is frequently used in large power plant generators.
Isolation transformer – It is a transformer especially intended to prevent leakage current from passing from its primary circuit to the secondary circuit.
Isolation valve – It is a valve in a fluid handling system which stops the flow of process media to a given location, normally for maintenance or safety purposes.
Isometric – It is a crystal form in which the unit dimension on all three axes is the same.
Isometric drawing – This drawing is used for piping. Isometric drawing is 3-D representation of piping on two dimensions of the drawing sheet. Isometric drawing covers a complete line as per the line list connecting one piece of equipment to another. It shows all information necessary for the fabrication and erection. It is not drawn to scale but is to be proportional for easy understanding. Dimensions are given relative to centre-line of piping. Isometric drawing also includes (i) plant North with the direction so selected as to facilitate easy checking of general arrangement drawing with isometric drawing, (ii) dimensions and angles, (iii) reference number of piping and instrument diagrams (P&IDs), general drawings, line numbers, direction of flow, insulation and tracing, (iv) equipment location and equipment identification, (v) nozzle identification on the connected equipment, (vi) details of flange on the equipment if the specification is different from the connecting piping, (vii) size and type of every valve and direction of operation, (viii) size and number of control valve, (ix) location, orientation and number of each equipment, (x) field weld, preferred in all directions to take care of site variations (it can also be covered with a general note), (xi) location of high point vents and low point drains, which is preferably covered with a standard arrangement note, (xii) any special requirement such as line to be tested prior to installation etc., (xiii) bill of materials, and (xiv) requirements of stress relieving, seal welding, pickling, and coating etc.
Isomorphous – It is having the same crystal structure. This normally refers to intermediate phases which form a continuous series of solid solutions.
Isomorphous system – It is a complete series of mixtures in all proportions of two or more components in which unlimited mutual solubility exists in the liquid and solid states.
Isostatic mould – It is a sealed container of glass or sheet of carbon steel, stainless steel or a nickel based alloy
Isostatic pressing – It is a process for forming a powder metallurgy compact by applying pressure equally from all directions to metal powder contained in a sealed flexible mould.
ISO system management standards – These are standards are for management systems. A management system is the way in which an organization manages the interrelated parts of its operations in order to achieve its objectives. These objectives can relate to a number of different topics, including product or service quality, operational efficiency, environmental performance, health and safety in the workplace and many more. The level of complexity of the system will depend on each organization’s specific context. These standards include ISO 9000 for quality management, ISO 14000 for environment management, ISO 50001 for energy management, ISO 45001 for occupational health and safety, and ISO 27000 for Information security management etc. These standards have a set of individual but related international standards.
Isothermal annealing – It is the austenitizing of a ferrous alloy, then cooling it to and holding at a temperature at which austenite transforms to a relatively soft ferrite-carbide aggregate.
Isothermal forging – It is a hot-forging process in which a constant and uniform temperature is maintained in the work-piece during forging by heating the dies to the same temperature as the work-piece. In the isothermal forging process, the dies are maintained at the same temperature as the forging stock. This eliminates the die chill completely and maintains the stock at a constant temperature throughout the forging cycle. The process permits the use of extremely slow strain rates, thus taking advantage of the strain rate sensitivity of flow stress for certain alloys. The process is capable of producing net shape forgings that are ready to use without machining or near-net shape forgings that require minimal secondary machining.
Isothermal transformation – It is a change in phase which takes place at a constant temperature. The time needed for transformation to be completed, and in some cases the time delay before transformation begins, depends on the quantity of super-cooling below (or super-heating above) the equilibrium temperature for the same transformation.
Isothermal transformation (IT) diagram – It is a diagram which shows the isothermal time needed for transformation of austenite to begin and to finish as a function of temperature. It is also called as time-temperature-transformation (TTT) diagram or S-curve. Isothermal transformation diagram illustrates the isothermal process of austenite precipitation. In this diagram, the transformation time is in the X-axis shown on the logarithmic scale and the temperature is plotted on the Y-axis. From this diagram, the incubation period (left hand curve) can be determined and also the time needed for completion of the process (right hand curve). The instant, steel passes the points A3 temperature and A1 temperature during quenching, is normally taken as the zero-time reference. The time required to achieve the temperature of the quenching medium is frequently neglected. The start and finish of the transformation are difficult to determine from the transformation curve behaviour at the initial and final sections of the curve. Hence, the lines of the isothermal transformation diagram normally correspond to a certain final volume which has undergone transformation, e.g., 2 % and 98 % for the transformation start and finish, respectively. The volume value is normally not shown in the isothermal transformation diagram.
Isotone – It consists of one of two or more atoms which display a constant difference A-Z between their mass number A and their atomic number Z. Hence, despite differences in the total number of nuclear constituents, the numbers of neutrons in the nuclei of isotones are the same.
Isotope – It consists of the atoms of the same element which have the same number of protons but different numbers of neutrons. Hydrogen has three isotopes – all with one proton but with zero (normal hydrogen), one (deuterium) or two (tritium) neutrons in the nucleus. Similarly, the two common isotopes of Uranium, U-235 and U-238 both have 92 protons in their nuclei but 143 (235-92), or 146 (238-92) neutrons respectively.
Isotropic – It means having uniform properties in all directions. The measured properties of an isotropic material are independent of the axis of testing.
Isotropic materials – These are those materials whose properties remain the same when tested in different directions. Isotropic materials differ from anisotropic materials, which display varying properties when tested in different directions. Common isotropic materials include glass, plastics, and metals.
Isotropy – It is the condition of having the same values of properties in all directions.
Item – It is an object or quantity of material on which a set of observations can be made. It is also an observed value or test result got from an object or quantity of material.
Iterative learning control – It is a technique for improving the accuracy of control systems which carry out the same sequence repeatedly.
ITmk3 process – It is also known as Ironmaking technologies (IT) mark 3 and is one of the coal reduction technologies. It is a rapid ironmaking process which includes reducing of ore, carburizing and melting iron and separating slag, all at relatively low temperatures. The four-step process consists of (i) agglomerating iron-ore and coal, (ii) reducing and melting of the agglomerates, (iii) separating of metallic iron from slag, and (iv) treating of exhaust gases and recovering of the heat. In this process, iron ore concentrate and non-coking coal (reducing agent), limestone (flux), and bentonite (binder) are mixed together and agglomerated into green self-reducing pellets. These pellets are fed into a rotary hearth furnace (RHF) where self-reducing, fluxing dried green balls are reduced, carburized and smelted. The product is granular iron called iron nuggets.
ITS-90 – ITS stands for international temperature scale. ITS-90 is defined for temperatures above 0.65 K and up to the highest temperature measurable according to Planck’s law for monochromatic radiation. The temperature measured with this scale (T90) is the closest to the thermodynamic temperature. This means it is universal. ITS-90 covers several temperature ranges. For each temperature range, it therefore defines fixed temperature points and a specific instrument for measurement and interpolation between these fixed points. The fixed temperature points correspond to phase transitions in pure substances. For example, the freezing points of zinc, tin, or silver, the melting point of gallium, or the triple points of oxygen, mercury or water.
Izod impact test – It is a type of impact test in which a V-notched sample, mounted vertically, is subjected to a sudden blow delivered by the weight at the end of a pendulum arm. The energy needed to break off the free end is a measure of the impact strength or toughness of the material. Izod impact testing is similar to the Charpy V-notch sample. The principal difference is that the sample is gripped at one end only, allowing the cantilevered end to be struck by the pendulum. An advantage of this method is that several notches can be made in a single sample and the ends broken off one at a time. The disadvantage which has caused it to lose the popularity is that the required time needed for clamping and method of clamping the sample in an anvil precludes low-temperature testing. Izod samples can also be round. All dimensional tolerances are +/- 0.05 millimeters unless otherwise specified. The clamping surfaces of the sample are flat and parallel within 0.025 millimeters. Finish on unmarked parts is 2 micrometers. Striker width is to be greater than that of the sample being tested. Several testing equipments can be used for both Charpy and Izod testing.
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