Complex ferritic structures obtained by three different heat treatments: differences and similarities

Abstract

Recently, a new processing concept known as quenching and partitioning (Q&P) has been proposed for designing high strength steels. This process involves quenching austenite below the martensite-start temperature, followed by a partitioning treatment to enrich the remaining austenite with carbon, thereby stabilizing it to room temperature. The resultant microstructures mainly consist of tempered martensite and retained austenite so that a higher strength can be achieved as compared to conventional TRIP steels. In high silicon hypereutectoid steels, lath-like ferrite matrix and a significant amount of ductile austenite that improves the work-hardening of the complex composite structure by TRIP effect can be also achieved by more conventional heat treatments such as an isothermal bainite treatment (B) or a traditional quench and temper (Q&T).