Hot strip mill as an experimental tool

Abstract

The occurrence of carbonitride precipitation during the short interpass times associated with hot strip rolling is considered, together with the interaction between precipitation and static recrystallization under these conditions. The characteristics of work hardening and of strain accumulation at the high temperatures (850 to 1050 °C) involved in strip rolling are described. Expressions are introduced that specify the kinetics of softening (by static or metadynamic recrystallization) during the interpass interval in various grades of steel. Using these kinetics in an appropriate mill model, the mean flow stresses pertaining to various mill stands are predicted. These values are compared with the measured ones derived directly from mill logs. It is shown how discrepancies between the predicted and measured values can be used to improve the accuracy of the expressions for the kinetics. This is one way in which a hot strip mill can be used as an `experimental tool'.