Plastic Strain Rate in Roll Bite Region During Rolling of Steels

During rolling, the workpiece usually undergoes severe reduction or deformation. The associated plastic strain, plastic strain rate, and temperature changes are enormous, especially in the roll bite region and have great effects on the microstructure and mechanical properties of the product. The plastic strain rate is a time-dependent quantity and its effect becomes prominent only at hot working conditions. As a result, the strain rate variation of the metals during rolling is extremely difficult to measure. Many studies have focussed on the measurement of plastic strain and temperature variations in steel rolling. In contrast, information on the plastic strain rate measurement in the roll bite region is limited. Consequently, the present research is aimed to study the plastic strain rate variations in the roll bite region. Measurement of microhardness is applied to quantify the accumulated plastic strain which is then used to correlate the associated plastic strain rate variations as determined by the finite element method (FEM). It has been found that the finite element predictions correlate very well with the microhardness measurements, and the plastic strain rate is extremely non-uniform in the bite region.