Difference between cold rolling and hot rolling

Compared with hot rolled strip, the rolling process of cold rolled strip has the following characteristics:

(1) the use of process lubrication and cooling, in order to reduce the deformation resistance of rolling and cooling roll;

(2) High tension rolling is used to reduce deformation resistance and maintain the stability of the rolling process. The average unit tension value used is 10% ~ 60% of the material yield strength, generally not more than 50%;

(3) adopt multi-roll rolling. Due to the work hardening caused by cold rolling, it becomes difficult to continue deformation when the total deformation amount reaches 60% ~ 80%. Therefore, intermediate annealing is needed to make rolling continue after material softening. This intermediate annealing may take place several times to obtain the required thin strip. The rolling between two intermediate anneals is called a rolling course. The annealing of cold rolled strip is carried out in a continuous annealing furnace or hood annealing furnace with protective gas. Minimum cold rolled strip thickness up to 0.05mm, cold rolled foil up to 0.001mm.

The material: VW 50065 CR4