Merits of Cold Rolled Steel

Cold-rolled steel is different from other types of steel in its make. Its properties give it advantages that set it apart. It is used widely across products big and small, like a cold rolled steel tube, part of a home appliance, etc. 

What is it?

“Cold-rolling” is one of the ways of treating a metal. For example, in a cold-rolled steel case, the sheet or strip is passed through rollers and compressed. The amount of tension applied to the steel determines how hard it is and its other properties. 

Steel is hot-rolled at a temperature higher than its recrystallization temperature. It is then pickled, which means removing the scales formed on the steel’s surface due to hot-rolling. Next, the steel is cooled up to room temperature. It is then rolled using cold rollers at a temperature below its recrystallization temperature. The thickness of the sheet or strip is then reduced in a cold rolling mill. In the end, the process gives a thin sheet usable for various purposes. 

Merits

Cold-rolled steel has many merits owing to its manufacturing process. Here is a list of them:

● Strength & tolerance

The process of cold-rolling makes the steel strong. Annealing in the cold-rolling process lets the metal heat and cool down. It relieves the stress in the metal and results in higher yield and tensile strength. The yield strength indicates the steel’s ability to tolerate stress to the point beyond which it begins to deform. The deformation is then irreparable. Tensile strength indicates the steel’s ability to withstand stress to the point beyond which it breaks or cracks. Annealing causes the structure of the steel to reorient at the micro-level, leading to its hardening. This makes cold-rolled steel around 20% stronger than hot-rolled steel.

● Thinner and lighter

Cold-rolled steel sheets are thinner than hot-rolled ones. This is because the rolling process reduces the thickness while keeping its strength intact. This allows it to be used in products with small dimensions like car parts, home appliances, etc. This also makes it lighter compared to other steel products and helps save on transportation costs.

● Smooth

This type of steel sheet has a smooth surface that looks polished. Compressing and flattening the sheet affects its texture and smoothens it. The metal grains of the steel get elongated, becoming tightly packed. The resultant look is polished without any indentations.

● Better accuracy in dimensions while manufacturing

Metals expand in volume when they are heated. After cooling down, they reach their original size. It happens in the hot-rolling process. However, in the case of cold-rolled steel, its temperature is brought back to room temperature after hot-rolling (heating it). Thus, there is no expansion and contraction. The steel sheet keeps its shape after cold-rolling. This is useful for keeping the dimensions accurate while manufacturing and maintaining straight edges.

For the reasons above, cold-rolled steel is beneficial to use. In India, JSW ColdRolled Steel is a leading steel manufacturer making products like cold rolled steel coil and sheets using state-of-the-art manufacturing facilities.