On the effect of heat treatment on the forming properties of pre-deformed low carbon steel

Strain hardening or cold work hardening usually accompanies most forming manufacturing processes as well as many other processes. This inevitable consequence, in a common functional sense, is undesirable from the design viewpoint. Therefore, attempts are always in progress to enhance the predeformed material in such a way to reduce this hardening effect. Annealing heat treatment is a familiar and effective technique that is frequently employed. In the current study, two annealing methods, used separately to investigate their effect on predeformed materials, are stress relief at 610 C° and process annealing at 710 C°. Both techniques have enhanced the resulting hardening stress to different degrees, depending on the degree of deformation and the value of true strain. Stress relief annealing tends to have the best outcome at moderate deformation levels from 0.12 to 0.16 predeformation strain. However, little gain is obtained at higher deformation levels especially at moderate to high true strain values. Process annealing is found to produce better qualitative and quantitative results than those obtained by stress relief annealing. Stress reduction has been achieved with process annealing within a wider domain of predeformation and true strains