The effect of predeformation level on the variability of forming properties of low carbon steel

In forming processes, metal is usually subjected to multi-stages of deformation. In order to process one stage effectively, actual information in terms of mechanical and forming properties of the preceding stage should be available to start with. It has long been assumed by those interested in forming processes that the forming properties (behaviors) remain constant regardless the number of stages involved. The validation of such an assumption is investigated in the current study for low carbon steel. This study has shown that the claim of forming parameters constancy is valid only within a limited domain of strain rate between 0.05 and 0.1. Outside this region, different behaviors of the forming parameters are noticed and, a compensatory action should be considered. Mathematical formulation of the experimental data has led to the establishment of many functional empirical relations by which a correction factor is determined. Better understanding of the problem is shown via the response surface approach including the 3-D representation and qualitative contouring plots.