Mechanical properties of cryogenically-rolled type 321 metastable austenitic steel

In this work, the mechanical behaviour of cryogenically-rolled type 321 metastable austenitic steel was studied. For this purpose, the material was rolled at a temperature of liquid-nitrogen to degrees of rolling reduction, the evolved grain structure was characterized by the electron-backscatter diffraction (EBSD) technique and mechanical properties were evaluated by tensile tests. It has been shown that rolling to 10 pct. of thickness reduction resulted in the extensive strain-induced martensitic transformation thus giving rise to abrupt material strengthening as well as essential degradation of ductility. However, with a further increase in the rolling strain, the volume fraction of martensite tended to saturate thereby leading to stabilization of the mechanical characteristics.