Basics of Rolling of Steel Nov21

Basics of Rolling of Steel...

Basics of Rolling of Steel  Liquid steel is usually cast in continuous casting machines in the shape of billets, blooms, or slabs. In some plants, it is also being cast in continuous casting machines in the shape of thin slabs or dog bone sections. These shapes are processed by hot rolling by passing them through plain or grooved cylindrical rotating rolls to produce plates, sheets, rods, structural sections, and tubes etc. Rolling process is one of the most important and widely used industrial metal forming operations. It provides high production and close control of the final product. It was developed in late 1500s. It accounts for 90 % of all metals produced by metal working processes. Rolling of steel is a metal forming process in which steel is passed through a pair of rotating rolls for plastic deformation of the steel. Plastic deformation is caused by the compressive forces applied through the rotating rolls. High compressive stresses are as a result of the friction between the rolls and the steel stock surface. The steel material gets squeezed between the pair of rolls, as a result of which the thickness gets reduced and the length gets increased. Rolling is classified according to the temperature of the steel rolled. If the temperature of the steel is above its recrystallization temperature, then the process is termed as hot rolling. If the temperature of the steel is below its recrystallization temperature, the process is termed as cold rolling. The rolls run on massive neck bearings mounted in housings of enormous strength and driven by powerful electric motors. These are known as mill stands. A rolling mill stand contains two or more rolls for plastic deformation of steel between rotating rolls. It basically consists of (i) rolls, (ii) bearings,...

Concrete and Reinforced Concrete...

Concrete and Reinforced Concrete Concrete is a composite building material made from a mixture of sand, gravel, crushed rock, or other aggregates (coarse and fine) held together in a stone like mass with a binder such as cement and water. The stone like mass is formed due to the hydration of cement and eventually due to its hardening. Sometimes one or more admixtures (plasticizers, super plasticizers, accelerators, retarders, pazolonic materials, air entertaining agents, fibers, polymers and silica furies) are added to change certain characteristics of the concrete such as its workability, durability, and time of hardening. Hardened concrete has a high compressive strength and a very low tensile strength. Concrete is one of the most popular materials for buildings because it has high compressive strength, flexibility in its form and it is widely available. The history of concrete usage dates back for over a thousand years. Contemporary cement concrete has been used since the early nineteenth century with the development of Portland cement. Despite the high compressive strength, concrete has limited tensile strength, only around 10 % of its compressive strength and zero strength after cracks develop. In the late nineteenth century, reinforcement materials, such as iron or steel rods, began to be used to increase the tensile strength of concrete. Today concrete is generally strengthened using steel bars known as reinforcement bars (rebars in short) in the tension zone. Such elements are known as ‘reinforced concrete’.  In the reinforced concrete, concrete and steel deform together and hence ribbed reinforcing bars are used for increasing the capacity to resist bond stresses. Reinforced concrete can be moulded to any complex shape using suitable form work. It has high durability, better appearance, fire resistance and is economical. It is a combination of concrete and steel wherein...

Employees Loyalty and the Organization...

Employees Loyalty and the Organization It is often said that it is extremely important for the organizations to provide a healthy work environment, in order to attract and retain qualified, highly committed, and loyal workforce, because committed and loyal employees reinforce employees’ motivation to act in the best interest of organizations they work for. Employees’ loyalty is important for the organization because employees are a vital resource for the organization, especially since they represent a significant investment in term of locating, recruiting, training let alone salaries, welfare plans, bonuses and rewards etc. Loyalty, as a general term, signifies a person’s devotion or sentiment of attachment to a particular object, which may be another person or group of persons, an ideal, a duty, or a cause. It expresses itself in both thought and action and strives for the identification of the interests of the loyal person with those of the object. Employee loyalty can be defined as a psychological attachment or commitment to the organization and develops as a result of increased satisfaction. Satisfaction results from a process of internal evaluation, and if an employee’s expectation level is met or exceeded, then satisfaction grows. Employee loyalty then develops into a generalized emotional attitude towards the organization. In other words, the more satisfied an employee is regarding his working environment, the more likely that he develops a sense of commitment towards the organization in general. Employees’ loyalty towards organization is often referred as organizational loyalty of the employees. It is the most important factor that determines the effectiveness and efficiency of the organization. It is the one of the key elements that measures the compatibility between employees on one hand and the organization on the other hand, since if this compatibility increases, the organization achieves a...

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...

Structural Steel – Preferred Material for Construction...

Structural Steel – Preferred Material for Construction Structural steel is not just a material which has only the technical competence. It has many other qualities that make it the preferred material for architects, designers and engineers. It is economical and provides great mechanical functionality; it permits the design of structures which are graceful, light and airy; it streamlines construction site processes; and it offers rapid execution. A major advantage, however, is the infinite freedom for creation which it provides to the architects, designers and engineers. The combination of structural steel with different materials lends themselves to rich and varied types of construction. When combined with glass, structural steel makes fabulous use of light and space. Structural steel is the material ‘par excellence’ when it comes to inventing new structures and forms. All solutions are possible, from the very simplest to the most challenging. Structural steel can be used for small buildings as well as large structures, for routine construction projects, and those subject to complex urban constraints. No other material is used to make structures which are so thin, light and airy. Forms can be created using different structural effects and envelopes with pure or finely sculpted curves. Architects, designers and engineers can give free reign to their imagination and creativity with structural steels. Structural steel is a standard construction material made from specific steel grades and is available in standard cross sectional shapes. This steel exhibits desirable physical properties such as strength, uniformity of properties, light weight and ease of use etc. This makes it one of the most versatile structural materials in use. Major applications for this steel is in high rise and tall multi-storey buildings, industrial buildings, towers, tunnels, bridges, road barriers, and industrial structures etc. Within the overall architectural concept,...