Study on Phase Transformation and Microstructure of Q&P Steel During Continuous Cooling

The phase transformation and microstructure of a QP steel during continuous cooling were studied by formastor thermal mechanical simulation. The continuous cooling transformation curves of the steel were drawn using thermal dilation method. Its microstructure was observed by an optical microscope. Continuous cooling transformation process of QP steel and its influences on microstructure were studied. The results show that the ferrite, bainite, pearlite phase transformation starting and ending temperature decrease with the increase of cooling speed; only when cooling speed is about 45 ℃/s, the martensite and remain austensite are obtained. The CCT curve provides the reference for establishing new processes.