What is the differnce between Hot Rolled steel and Cooled Rolled Steel?

Answer 1

Pretty much what the name implies: hot rolled the steel is rolled at high temperature - This gives the advantage of lower forming pressure because the steel is softer. Also it avoids the development of residual stresses in the steel, since it comes out (if properly controlled) in an annealled state (of course to get the desired properties, this form is then heat-treated).

For cold-rolled steel, this can be done even at room temperature - Disadvantage is the pressure required is much higher, advantage you don't risk getting burnt. But really the advantage of cold rolling is the development of residual stresses which if designed properly can strengthen the steel - Related to this is also the microstructural changes that happen when you plastically deform the steel - The grain structure is affected in a way that also strengthens the steel. Of course if any of these processes are not properly controlled, then the residual stresses (of in case of hot rolling improper cooling) can cause the final product to warp and even fracture.

Answer 2

Differnce between Hot Rolled steel and Cooled Rolled Steel

Hot rolled steel is typically cheaper than cold rolled steel due to the fact that it is often manufactured without any delays in the process.

Cold rolled steel is essentially hot rolled steel that has had further processing. The steel is processed further in cold reduction mills, where the material is cooled followed by annealing and/or tempers rolling.

Answer 3

Well, besides the temperature...

The properties of the steel are different when molding it to what is needed. Sometimes you will want more 'flexible' steel with greater 'spring' to it for certain applications, other times you might want the most rigid you can get. Using the temperature along with the steel composition helps to get what you want.

Answer 4

Hot rolled steel is rolled above it's crystalization temperature and coled rolled below. read all about at-