Chapter 15 - Modelling and Control of Temper Rolling and Skin Pass Rolling

Abstract

This chapter deals with temper rolling. Temper rolling is used either to eliminate upper and lower yield stress behavior, yield elongation, or to improve the surface of the strip or both. The final flatness is affected by temper rolling. In order to optimize the final properties of cold rolled steel, it is necessary to improve the control of the temper rolling process. A good predictor of the rolling force improves the process control. The main purpose of temper rolling of a low-alloyed low carbon steel strip is optimization of the mechanical properties. Properties of interest are the yield strength, which should be well defined at a certain level, and the existence of non-homogenous yield elongation caused by propagating of Lüder's bands. As a rolling process, temper rolling is similar to normal cold rolling in many ways. Both the processes are performed in the same type of rolling mills, using the same types of rolls with the same type of actuators for gauge, flatness, and surface roughness control. Besides adjusting the mechanical properties of the strip, temper rolling can provide the proper surface texture and good flatness. The same principles are applied for flatness control during temper rolling as during conventional cold rolling with large thickness reductions.