Deformation of inclusions during hot rolling of steels

Abstract

The deformability of inclusions during hot working of steels influences the final properties of the product. In the present work the inclusion behavior in flat hot rolling has been studied by using a developed rigid–viscoplastic finite element code. The analysis is based on the mesomechanical approach. This method connects the micromechanical behavior of the heterogeneous material with its in-service macroscopic behavior. The macro-model evaluates the deformation history throughout each sub-volume of the material without taking the influence of inclusions into account. The micro-model that includes inclusions makes use of the deformation history from the macro-model as boundary values. Thus a micro-model cell element is constructed to analyze the behavior of an inclusion. The cell element is subjected to the same deformation history as that inside a macro-model element. The influences of process parameters, such as rolling temperature, rolling reduction and friction at workpiece/roll interface, are investigated. The relative plasticity index of a silicate inclusion was found to be heavily dependent on the process parameters. The index got high values for high temperatures, low rolling speeds and rolling schedules built on small reduction/pass. Some results are consistent with existing experimental observations. Also the influence of friction, at the workpiece/roll interface, on the profile of the inclusion has been analyzed.