The kinetics of softening processes during hot working of austenite

Abstract

Modelling the microstructural changes and working forces during industrial hot working operations provides a powerful method of understanding and optimizing the interactions of material and process variables. It relies on the availability of basic quantitative relationships to describe the microstructure and flow stress in terms of the engineering variables. This paper briefly considers relationships which describe stress-strain characteristics and then concentrates on the relationships which describe the kinetics of static recrystallization and the resulting grain sizes. The empirical forms of equations for C-Mn steel are considered in detail in terms of the mechanisms involved. The important role of grain boundaries is emphasized and deficiencies in understanding of the basic mechanisms are pointed out. Despite these deficiencies, computed results for industrial hot rolling are in good agreement with observation.