Warm Working as a Potential Substitute for Hot Working of Austenitic Steel in Selected Applications

The conventional manufacturing route for austenitic steels involves casting, ingot breakdown, subsequent hot working, and finally cold working, with numerous intermediate heat treatment stages. In this study, the potential of warm working to substitute some steps of the conventional manufacturing process is examined. A low-carbon austenitic stainless steel, SS304L, is subjected to cold, warm, and hot deformation in light of recent understanding of warm working. The deformation response in these two regimes is compared on the basis of metallurgical, mechanical, and process variables. Metallurgical response is compared on the basis of resultant grain size and stability of microstructure to subsequent heat treatment. The differences in mechanical response in the two regimes are evaluated through analysis of flow curves. Finally, the important but often ignored parameter of process stability is examined by performing nonisothermal deformation and examining the effect on microstructure. The results are used to propose some applications where warm working can substitute hot and cold working.