Effects of Retained Austenite Conditions on the Ductility of the Advanced High Strength Steels
It was investigated that the effects of retained austenite (γR) conditions on ductility of advanced high strength steels for automotives. 0.4mass% C steels were heattreated in various austemper conditions to control the retained austenite conditions. In the result of the evaluation of mechanical properties of these steels, it was confirmed there were steels which indicated different elongation even if they had almost same volume fraction and carbon content of retained austenite. In order to clarify the reason, the conditions of retained austenite and work hardening behavior were investigated in detail. It was indicated that the existence of high carbon content region in a part of retained austenite promoted the deformation induced martensitic transformation in the high strain range and improved the elongation of AHSS.