Role of Lubrication during the Process of Metal Working Feb15

Role of Lubrication during the Process of Metal Working...

Role of Lubrication during the Process of Metal Working For understanding the role of lubrication during the processes of metal working, it is important to know the tribology of the lubrication. Tribology consists of boundary friction, which is associated with almost all operations of the metal working. It is caused by the relative movement of two adjacent surfaces under pressure. During the metal working processes, the relative movement between rolls and work piece is improved by the surface speed differential of the rolls Friction Friction plays an important role during metal working process. It is defined as the resistance to relative motion between two bodies in contact. It is an energy dissipating process, causing the temperature at the interface to rise and, if excessive, can result in surface damage. It also influences the deformation taking place in the metal working process. As per the earliest theories, friction is the result of interlocking two rough surfaces sliding along each other. Friction is actually brought on by a large number of variables, such as load, speed, temperature, the materials involved in the sliding pair, and the various effects of fluids and gases at the interface. Most commonly accepted theory of friction is based on the resulting adhesion between the severities of the contacting bodies. It has been seen that regardless of how smooth the surfaces are, they contact each other at only a fraction of their apparent area of contact. Thus, the load during the process of metalworking is supported with few severities in contact. Hence, the normal stress at the severity junctions is high. Under light loads, the contact stresses can only be elastic. However, as the load increases to some of the levels involved in the metal working process, elastic deformation of the severities...

Wire and Rod Drawing Process for Steel Nov13

Wire and Rod Drawing Process for Steel...

Wire and Rod Drawing Process for Steel Drawing of wire from steel rod is a metal working process used for the reduction of the cross-section of the rod. Similarly rods are drawn from steel rounds of larger diameters. During drawing the volume remains the same and hence there is increased in the length of the drawn wire or rod. It is carried out by pulling the wire/rod through a single or a series of the drawing dies. In the case of series of drawing dies, the subsequent drawing die is to have smaller bore diameter than the previous drawing die. Drawing is usually performed in round sections at room temperature, thus it is classified as a cold working process. However, it can be performed at higher temperatures for large wires to reduce forces. Drawing process normally is most frequently used to produce round cross sections, but squares and other shapes can also be drawn. Wire/rod drawing is an important industrial process, providing commercial products. Rod and wire products cover a very wide range of applications which include shafts for power transmission, machine and structural components, blanks for bolts and rivets, electrical wiring, cables, wire stock for fences, rod stock to produce nails, screws, rivets, springs and many others. Drawing of rods from steel rounds is used to produce rods for machining, forging, and other processes etc. Advantages of drawing in the above applications include (i) close dimensional control, (ii) good surface finish, (iii) improved mechanical properties such as strength and hardness, and (iv) adaptability to economical batch or mass production. In the process of drawing, the cross section of a long rod or wire is reduced or changed by pulling (hence the term drawing) it through a die called a draw die. Pulling of rod...

Basics of Pneumatics and Pneumatic Systems Nov14

Basics of Pneumatics and Pneumatic Systems...

Basics of Pneumatics and Pneumatic Systems Pneumatics has long since played an important role as a technology in the performance of mechanical work. It is also being used in the development of automation solutions.  Pneumatic systems are similar to hydraulic systems but in these systems compressed air is used in place of hydraulic fluid. A pneumatic system is a system that uses compressed air to transmit and control energy. Pneumatic systems are used extensively in various industries.  Most pneumatic systems rely on a constant supply of compressed air to make them work. This is provided by an air compressor. The compressor sucks in air from the atmosphere and stores it in a high pressure tank called a receiver. This compressed air is then supplied to the system through a series of pipes and valves. The word ‘Pneuma’ means air. Pneumatics is all about using compressed air to do the work. Compressed air is the air from the atmosphere which is reduced in volume by compression thus increasing its pressure. It is used as a working medium normally at a pressure of 6 kg/sq mm to 8 kg/sq mm. For using pneumatic systems, maximum force up to 50 kN can be developed. Actuation of the controls can be manual, pneumatic or electrical actuation. Compressed air is mainly used to do work by acting on a piston or vane. This energy is used in many areas of the steel industry. Advantages of pneumatic systems Pneumatic systems are widely used in different industries for the driving of automatic machines. Pneumatic systems have a lot of advantages. High effectiveness – There is an unlimited supply of air in the atmosphere to produce compressed air. Also there is the possibility of easy storage in large volumes. The use of...

Steel Wire Ropes

Steel Wire Ropes Steel wire rope, is also known as steel cable.  It is a type of rope which consists of several strands of steel wire laid (twisted) into a helix. Modern wire rope was invented by the German mining engineer Wilhelm Albert in the years between 1831 and 1834 for use in mining. It was quickly accepted because it proved superior to metal chains and ropes made of hemp which was used before. Wilhelm Albert’s first ropes consisted of three strands consisting of four wires each. Wire rope industry in India, which was founded very early, started with coconut fibre ropes, switched to jute fibre, on to ‘Manila’ ropes and then to steel ropes. With the change in the needs, the designing of the wire ropes also undergone major changes with respect to the core, overlay and the weight requirement etc. Wire rope is a machine which consists of a number of precise moving parts, designed and manufactured to bear a definite relation to one another. In fact, some wire ropes contain more moving parts than many complicated mechanisms. For example, a six strand wire rope, laid around and independent wire rope core each strand and core with 49 wires, contains a total of 343 individual wires. All these wires are to work together and move with respect to one another if the rope is to have the flexibility necessary for successful operation. Wire rope has three components (Fig 1) consisting of wires, strands and core. The basic unit of a wire rope is wire which is carefully processed and drawn from selected grades of steel to predetermined physical properties and sizes. A predetermined number of finished wires are helically laid together in a uniform geometric pattern to form a strand. The process is carried out with precision and...

Hydraulic fluids

Hydraulic fluids Hydraulic oils are also called hydraulic liquids or hydraulic fluids. They are the medium by which power is transferred in hydraulic equipment. Hydraulic fluids have the primary purpose of transferring potential or kinetic energy (pressure and movements), create volume flow between pump and hydrostatic motor, and reduce the wear of parts that rub against each other. In addition, they protect the system from corrosion and help carry away the heat produced during energy transformation. The operating practices of yesterday in industry have changed a lot. But steady and dependable, hydraulic fluid technology did not change much for decades. But today, the pressure is on hydraulic systems. Hydraulic systems are expected to deliver optimum performance while operating at higher pressures, temperatures, and tougher operating conditions. Common hydraulic fluids are based on mineral oil or water. These oils have generally low compressibility. Hydraulic oils are circulation quality oils since they are in continuous use in an enclosed system with practically very little residence time in a reservoir or a storage tank. Hydraulic fluid has to perform the following tasks: Energy transmission Lubrication Heat removal The primary function of a hydraulic fluid is to convey power. However there are other important functions of hydraulic oils such as protection of the hydraulic machine components. The main functions of hydraulic oil and the corresponding properties of the hydraulic oil which affects its ability to perform the required function are given below: Hydraulic oil as medium for power transfer and control needs low compressibility (high bulk modulus), fast air release, low foaming tendency and low volatility. Hydraulic oil as medium for heat transfer requires good thermal capacity and conductivity. Hydraulic oil as sealing medium must have adequate viscosity and viscosity index as well shear stability. For hydraulic oil to perform the function...