Influence of Heat Treatment on Mechanical Properties for Cold Worked 304 Austenitic Stainless Steel

Austenitic stainless steels are widely used in a variety of industries, such as power plants, aerospace, automotive, construction and electronics, due to their excellent mechanical properties including ductility, toughness and corrosion resistance. For application in various industries, many parts and products require plastic processes such as cold rolling, cold forging and bending. These processes cause a phenomenon in which the strength is increased but the toughness is lowered by the plastic deformation. However, heat treatment of the plastic-deformed material can improve mechanical properties by grain refinement due to recrystallization and phase transformation. In this study, the effect of grain refinement and phase transformation by heat treatment of cold-worked austenitic stainless steels were evaluated in order to improve mechanical properties such as toughness and strength. After the cold working process, strength and hardness were increased by the phase transformation of martensite from austenite, and an increase in dislocations by plastic deformation. After heat treatment, the ductility and toughness of the austenitic stainless steels strengthened by cold working process were increased due to grain refinement caused by recrystallization of the remaining austenite, and the reverse transformation from martensite to austenite induced by heat treatment. Key words: austenitic stainless steel, recrystallization, grain refinement, phase transformation, cold working