Concept of a Rolling Mill In Steel Plant

Rolling is a process in which the metal strip is pressed through two or multiple roles to form metals that maintain uniform thickness and consistency. It is a well-known metalworking process used in the production of steel.

A machine designed to perform this process is called a rolling mill. 

Types of Rolling Mills

● Two high rolling mills: Two rollers in a two-high rolling mill rotate in the opposite direction and convert a workpiece into the desired shape.

● Three high rolling mills: They have a stand with three parallel rolls above each other.

● Four high rolling mills: A roll stand with four parallel rolls placed above another. 

● Tandem rolling mills: It comprises a set of two or three strands of roll placed in parallel alignment.

● Cluster rolling mills: Two or more larger rolls support each active roll for rolling hard material.

Rolling Processes

Temperature is one of the essential features of performing this type of rolling. Therefore, we can classify rolling processes into two types based on the temperature of the metal rolled.

● Hot Rolling

Hot rolling is the process where the temperature of the metal rolled is above the recrystallization temperature to produce hot-formed steel. Here, the metal is heated at a desirable temperature and passed through one or more rolling mills to obtain the desired shape. As less force is involved here, there is a reduction in the quality of the surface of the finished metal.

This hot-rolled product is produced at a very high temperature of over 1,700 Degrees Fahrenheit. Since the products cool from very high temperatures, the corners of the bars and plates become slightly rounded instead of a perfect square. So hot rolled products are popular when precise shapes and tolerances are not required. 

● Cold Rolling

If the rolling of the metal is done at or near room temperature, it is termed cold rolling. When the hot-rolled sheet products are cooled, they are re-rolled at room temperature, resulting in cold-rolled products. 

Cold rolling produces more robust and more durable steel products. In addition, this process offers a good surface finish as more force is involved. They also give a glossy and smooth finish. Tubes maintain straightness, and the concentric uniformity is much better. 

Application of Rolling

The rolling process is a regular operation in various industries like :

● Some cold-rolled products, like wire sheets or wire, are used to make screws, threaded parts, and bolts.

● They are also externally used in automotive industries like doors, electrical motors, etc. 

● Some hot-rolled sheet products like rods, seamless hollow tubes, rails, and structural bars are common in making body panels, piping, tubes, and construction materials. 

● Plates, steel sheets, bearings, and turbine rings are produced by rolling.

● Rolling is used for cutting gears on gear blanks and producing cross-sections of large sections.

So, if you want good hot-rolled sheet metal, purchase from a reliable steel manufacturer like JSW HotRolled Steel to get high-quality steel products at reasonable prices.