Prediction of the flow stress and grain size of steel during thick-plate rolling

A strip is discontinuously deformed during the hot rolling process; the strip is deformed at the roll stands, but not deformed and only coded between passes. In general, the flow stress and grain size of the strip vary through the deformation and non-deformation periods during the process. In the present study, a coupled model consisting of recrystallization and flow-stress models is proposed for the prediction of the flow stress and of the grain size in the austenite region of steel. Utilizing the finite element analysis technique, the coupled model is applied to the conventional rolling and controlled rolling of thick plates. As a result, variations of grain size, flow stress and retained strain with respect to the process time were predicted, including those variations developed the thickness.