Influence of Cr and Ni on Microstructural Evolution during Heat Treatment of Low Carbon TRIP steels

Abstract

The effect of Cr and Ni addition on microstructural evolution in the transformation induced plasticity (TRIP) steel is investigated. Both Cr and Ni increase the austenite fraction at austempering temperature. The austenite in Ni-added steel is stable during final cooling after austempering; however, a considerable amount of austenite transforms to martensite in Cr-added steel. The instability of austenite in Cr-added steel is attributed to the increase of hardenability, which inhibits the carbon enrichment in austenite by suppressing ferrite formation.