The main advantages of cold working are.
Cold rolled sheet metal vs hot rolled.
Generally speaking hot roll steel has a rougher surface wider tolerances and lower cost.
In comparison a cold rolled steel product with the same chemical composition has a yield strength of 365 mpa.
In this article we will compare hot rolled vs cold rolled steel sheets.
Both hot rolled steel and cold rolled steel start out in essentially the same way and both can have the same grades and specifications.
Each type of steel has its advantages and disadvantages and costs for the two types of steel are also different.
As an example a hot rolled steel product may have a yield strength of 235 mpa.
Cold rolling is done when the metal is able to form new grains as the old ones are deformed by rolling and bending the metal.
Typically mills take hot rolled steel after it s mostly or completely cooled and work it to its final dimension by either rolling it extruding it or drawing the metal over a mandrel.
Cold rolled has sharper corners and more precise dimensions than hot rolled.
Whereas cold rolled steel is processed in cold reduction mills followed by annealing and tempering.
Hot rolled steel comes with a scaly surface slightly rounded edges and corners and the surface is non oily.
The differences between hot rolled steel and cold rolled steel relates to the way these metals are processed at the mill and not the product specification or grade.
Hot rolled steel involves rolling the steel at high temperatures where cold rolled steel is processed further in cold reduction mills where the material is cooled followed by annealing and or tempers rolling.
During the hot rolling process steel is heated to its melting point while being worked changing the composition of the steel to make it more malleable.
Hot rolled steel is rolled or shaped at a high temperature while cold rolled steel is rolled at room temperature.
Hot rolling and cold rolling are two methods of shaping steel.
Cold rolled has a smooth and shiny finish while hot rolled has a grey and scaly finish.
But cold rolled steel undergoes additional processing steps resulting in improved properties that can be exploited for different applications.
Thus the yield strength of cold rolled steel is higher than that of hot rolled steel.
Once hot rolled steel has cooled it is then re rolled at room temperature to achieve more exact dimensions and better surface qualities.
There are some fundamental differences between these two types of metal.
During cold rolling the steel is annealed or exposed to heat and allowed to cool which improves ductility.
Cold rolled steel is essentially hot rolled steel that has been through further processing.
Hot rolled steel involves rolling the steel above re crystallization temperatures.
In short hot rolled steel is processed at the mill at high temperatures and that s it.
Cold rolled steel has an oily or greasy finish very smooth surface and very sharp edges.
