Compressive flow stress characteristics of carbon steels and stainless steels during cold forging

Flow stress-strain curves of material are necessary in numerical analysis such as finite element analysis of the cold forging process. The compressive flow stress-strain in carbon steels and stainless steels at various temperature in the range of cold forming were studied by static and dynamic upsetting tests. The stress-strain curves of feritic stainless steel are similar to those of carbon steel in the temperature range from 30 to 200°C. Work-hardening behavior of austenitic stainless steel is more significantly affected by deformation temperature than that of carbon and feritic stainless. The flow stress is modeled as a function of strain, strain rate and temperature. The validity of this equation is examined through comparison between load measured in upsetting test and that obtained by numerical simulation.