The contributions of work-hardening of austenite and the presence of martensite on the hardening of an AISI 304L stainless steel were evaluated based on plastic deformation under different reductions in thickness at two rolling temperatures. The cold deformation temperatures of 300 K and 373 K were chosen to induce strain-hardening plus strain-induced martensitic transformation in the former and strain-hardening in the latter. This made it possible to elucidate the real effects of strengthening mechanisms of metastable austenitic stainless steels during mechanical working.

A hot compression test was conducted on a Gleeble-3500 thermo-simulation machine to study the critical conditions and kinetics of dynamic recrystallization in a high-carbon tool steel. The critical conditions for the initiation of dynamic recrystallization were determined using the working-hardening theory. The quantitative relationship between the critical characteristics of dynamic recrystallization and the hot deformation parameters were elucidated based on two different methods:the apparent method and physically based method. It was found that the two methods both have high applicability for the investigated steel, but the physically-based method needs less parameters and makes it possible to study the effect of different factors. A dynamic recrystallization kinetics model was used to calculate the recrystallization volume fraction under different conditions. The calculation results matched well with the data obtained from the flow curves.