THE ROLLING

 

The rolling is a process of continuous plastical strain obtained by the mill rolls. That strain is characterized by a thickness reduction and an elongation of the rolled plate thanks to successive passes between the rolls. The wrought coefficient is the ratio between the product sections before and after rolling. The rolling modifies the primary crystalline structure of the ingot, refines the graine, homogenizes the compound and improve the characteristics, especially in the longitudinal direction, because of the orientation given to the chrystalline structures.

The heat rolling allows to reduce quickly the thickness of the plates under high temperature that increases the ductility for avoiding the breaking risks.

The cold rolling in made at ambient temperature and requires a great lubrication; it allows to obtain some highly precised plates or strips at the level of size characteristics, homogeneity of the alloy structure and of the surface quality. It is used for the manufacturing of thin sheets.