Energy Management in Small and Medium sized Re-rolling mills...

Energy Management in Small and Medium sized Re-rolling mills Energy consumption in small and medium sized re-rolling mills takes place in two forms namely (i) electrical energy, and (ii) fuel or heat energy. Electrical energy is used directly in main rolling process for shaping of hot billets into rolled product (rolling mill, and shears etc.), in reheating furnace (coal pulverizer, blower, and pusher etc.) and also in auxiliary (roll turning machines, pumps, man coolers, overhead crane etc.), and shop lighting. Fuel energy is used in the reheating furnace for raising the temperature of the feed material to desired temperatures (generally 1150 deg C–1250 deg C). The division of the energy in these two forms normally varies from mill to mill based on the practices employed as well facilities installed in the re-rolling mills in SME (small and medium enterprise) sector. However, the share of electrical energy in small and medium sized mill generally varies in the range 20 % to 30 %. Consumption of fuel energy takes the major share of the energy consumption and usually constitutes 70 % to 80 %. From a theoretical perspective, the energy in hot rolling is primarily determined by the requirements of reheating of feed material. The theoretical energy for deformation is only 0.02 GJ/ton (around 5000 kcal/ton), compared to 0.83 GJ/ton (around 200,000 kcal /ton) for heating billets when charged cold in the reheating furnace. Though it is not technically feasible to achieve theoretical energy consumption figures, but the energy efficiency of the rolling mill is depends upon how close it is to the theoretical consumption. Management of electrical energy consumption Out of the total electrical energy consumed by a re-rolling mill, the share of the process of rolling is in the range of around 60 %...

Understanding Rolling Process in Long Product Rolling Mill Nov27

Understanding Rolling Process in Long Product Rolling Mill...

Understanding Rolling Process in Long Product Rolling Mill  Steel rolling consists of passing the material, usually termed as rolling stock, between two rolls driven at the same peripheral speed in opposite directions (i.e. one clockwise and the second anti-clockwise) and so spaced that the distance between them is somewhat less than the thickness of the section entering them. In these conditions, the rolls grip the material and deliver it reduced in thickness, increased in length and probably somewhat increased in width. This is one of the most widely used processes among all the metal working processes, because of its higher productivity and lower operating cost. Rolling is able to produce a product which is having constant cross section throughout its length. Many shapes and sections are possible to roll by the steel rolling process. Steel sections are generally rolled in several passes, whose number is determined by the ratio of initial input material and final cross section of finished product. The cross section area is reduced in each pass and form and the size of the stock gradually approach to the desired profile. Rolling accounts for about 90 % of all materials produced by metal working process. It was first developed in the late 1500s. Hot Rolling is carried out at elevated temperature above the re-crystallization temperature. During this phase, the coarse-grained, brittle, and porous structure of the continuously cast steel is broken down into a wrought structure having finer grain size and improved properties. A long product rolling mill comprised of equipment for reheating, rolling and cooling. The primary objectives of the rolling stage are to reduce the cross section of the incoming stock and to produce the planned section profile, mechanical properties and microstructure of the product. Major parameters in the three...

Basics of Hydraulics and Hydraulic Systems Nov07

Basics of Hydraulics and Hydraulic Systems...

Basics of Hydraulics and Hydraulic Systems Hydraulics is the generation of forces and motion using hydraulic fluids which represents the medium for the transmission of power. Hydraulic systems are extremely important for the operation of heavy equipments. The word ‘hydraulics’ is based on the Greek word for water and originally meant the study of the physical behaviour of water at rest and in motion. Today, the meaning has been expanded to include the physical behaviour of all liquids, including hydraulic fluids. Hydraulic systems are not new to the industry. They have provided a means for the operation of many types of industrial equipments. As the industrial equipments have become more sophisticated, newer systems with hydraulic power are being developed. Hydraulic systems are used in modern production plants and manufacturing installations and they play a major role in steel industry, mining, construction and materials handling equipment. Hydraulic systems are used to operate implements to lift, push and move materials. Wide range of applications of hydraulic systems in the industry has only started since 1950s. Since then, this form of power has become standard to the operation of industrial equipments. Today hydraulic systems hold a very important place in modern automation technology. There are many reasons. Some of these are that hydraulic systems are versatile, efficient and simple for the transmission of power. Transmission of power is the job of the hydraulic system, as it changes power from one form to another. In hydraulic systems, forces that are applied by the fluid are transmitted to a mechanical mechanism. To understand how hydraulic systems operate, it is necessary to understand the principles of hydraulics. Hydraulics is the study of liquids in motion and pressure in pipes and cylinders. The science of hydraulics can be divided into two...