Hot rolled steel is a steelmaking process that involves heating steel at its recrystallization temperature or above it and shaping it while it is hot.Rod wires are formed by the hot rolling process which means billets are rolled at 1700 degrees in rolling mills.  Rod wire is hot rolled, but not all steel is shaped when heated. Cold rolled sheets, unlike hot rolled rod wires are made at room temperature.  Cold rolling is an extension of hot rolling, for the steel is heated above its recrystallization temperature, cooled down and then drawn at toom temperature. As the process sounds,cold rolled sheets requirehigher pressure in order to be rolled and drawn below its recrystallization temperature. Since coldrolled sheets can be tampered wayunder the recrystallization temperature,they offer many benefits. Here are a few of the mainadvantages of coldrolled steel.

 

High Strength

Coldrolled sheetsaremuch stronger than hotrolled steel. Since the steel is compressed or shaped by rollers at room temperature, it tends to gain strength due to strain hardening. On an average cold rolled steel is 1.2 X as string as hot rolled steel. This is not the case for all cold rolled products but most of them are 20% stronger on an average.

 

Enhancedfinish on the Surface

Apart from being stronger than hot rolled steel, coldrolled sheets have a more perfect finish. This is because they are shaped after being cooled down, making them retain their shape, smoothness and precision. Hot rolled steel on the other hand cools down after being rolled, thus the final shape and surface differs and it has imperfections. Cold rolled steel’s surface finish is improved – it is smooth& hasvery few surface imperfections. This makes it both – aesthetically pleasing and suited for applications that require precise dimension such as bridge construction etc.

Tighter Tolerances

Cold rolled sheets have tighter tolerances as compared to hot rolled steel. In the metalworking industry, ‘tolerance’ is the complete thickness of metal. Without compromising on its strength, Cold-rolled steel is characteristically thinnerthan hot-rolled steel. Such tight tolerance is hard to find in alternate steelmaking procedures.

 

Various Options

Cold rolled steel offer various versions of the steel such as skin rolled, half hard, quarter hard and full hard rolled steel. These multiple options make them suitable for various applications. Out of all these options, the most preferable steel is the full-hard cold rolled sheets due to theirtightest tolerances. This type of steel has a reduced thickness of almost half of its counterparts and strength is very higher. Other variations are not as thin.