MATHEMATICAL-MODELING OF MEAN FLOW-STRESS DURING THE HOT STRIP ROLLING OF MULTIPLY-ALLOYED MEDIUM-CARBON STEELS

The kinetics of static, dynamic and metadynamic recrystallization appl icable to a Cr-Mo-V-Ni-Nb steel were determined by means of torsion te sting. A mathematical model for the flow stress was then drawn up base d on the Misaka equation, but which incorporates the effects of dynami c, metadynamic, and static recrystallization. In this way, it takes bo th the accumulated strain as well as microstructural evolution into ac count. In addition, mill log data obtained from the Wakayama Steel Wor ks of Sumitomo Metal industries were converted into mean flow stresses (MFS's) using the Sims approach. The operating data obtained in this way are compared with the predictions of the model, and excellent agre ement is obtained between the measured and predicted MFS values over t he whole range of rolling temperatures and conditions. The predictions indicate that dynamic, followed by metadynamic, recrystallization lak es place during finish rolling of this grade.