Influence of Cold Drawing on Phase Transformation and Tensile Properties of FeCrMn Austenitic Stainless Steel 201

Manganese stabilizes the austenite and reduces the stacking fault energy in face-centered cubic (FCC) structures, promoting the formation of hexagonal and cubic structures. This study investigates the phase transformation and mechanical behavior of extremely low-carbon FeCrMn austenitic stainless AISI 201 steel subjected to cold drawing in three stages, ultimately reaching a true strain of 0.93. The objective is to examine the transformation from the parent FCC structure to hexagonal close-packed and body-centered cubic structures as a combination of transformation-induced plasticity and twinning-induced plasticity phenomena. X-ray diffraction and electron backscatter diffraction analyses are utilized to investigate phase transformations under significant plastic deformation and the crystallographic orientation relationships between phases. Additionally, tensile and hardness tests are performed to assess the impact of plastic deformation on mechanical properties. Results indicate that a true strain of 50% is optimal for balancing strength and ductility in CrMnFe austenitic stainless steel. After applying a true strain of epsilon 1 = 26.7%, yield strength (YS) increases by 192% and ultimate tensile strength (UTS) by 35%, while elongation reduces by 41%. With a further strain of epsilon 2 = 57.5%, YS increases by 71% and UTS by 44%, but elongation drastically decreases by 94%. Applying the final strain of epsilon 3 = 94.0%, YS and UTS only increase by 3% and 2%, respectively, while elongation further reduced by 40%. These findings suggest that a true strain of 50% shall be considered the maximum reduction for maintaining a balance between strength and ductility in CrMnFe austenitic stainless steel.