Martensite Transformation Start Temperature During Quench and Austempering in Fe-8Ni-0.2C Alloys

It is important for the improvement of mechanical properties quenching and partitioning (QP) steels to control martensite transformation behavior stability untransformed austenite. In this study, we evaluated restart temperature (Mr) via a dilatometer during reheat austempering pattern. This heat pattern corresponding typical treatment QP steel involves TQ, between start (Ms) finish temperature, above Ms. Fe-8Ni-0.2C alloy, Mr equals regardless progress bainite at 673 K (400 °C). Fe-8Ni-1Si-0.2C decreases parabolically from TQ with transformation, corresponds assumed carbon concentration by transformation. These results indicate that self-stabilization entire austenite first quench Ms was preserved, Moreover, stabilization in added self-stabilization.