Effect of cooling path on phase transformation of boron steel 22MnB5

Abstract

The properties of hot formed parts using boron steel are controlled by the microstructure evolved in hot working process. In order to obtain the required mechanical properties, the relationship among temperature history, phase transformation and final microstructure needs to be investigated and established. The dilatometric experiments with different cooling rates and dwell temperatures of boron steel 22MnB5 in different heat treatment processes were conducted to explore the effect of cooling path on the phase transformation of steel from austenite to ferrite, bainite and martensite. Metallographic analysis was then done to verify the existence of the corresponded microstructure of the heat treated specimen. The information about cooling parameters and phase transformation can thus help the design of hot forming process and the control of mechanical property of the parts formed.