Subcritical Heat Treatment of Cold Rolled Multi-phase TRIP Steel

摘要

TRIP (TRansformation Induced Plasticity) steels can be used in the cold rolled and 'TRIP annealed' condition. TRIP annealing is designed to produce the complex microstructures, comprised of ferrite, bainite, retained austenite, which achieve the best combination of strength and formability. Thus, the processing of these steels requires careful selection and delicate control of temperatures and holding times. In this context, this project has been carried out to design an alternative process for TRIP steel, using a relatively simple Subcritical heat-treating process. Basically, the concept is to cold roll the TRIP steel to produce strain induced martensite, as well as work hardened ferrite and bainite, and then to 'conventionally' anneal the steel to produce tempered martensite and bainite, as well as recrystallized ferrite. The microstructural evolution during this Subcritical heat treatment, and the subsequent mechanical properties will be presented in this paper.