Influence of Tempering Time on Microstructure and Properties of New Type Bainite Cast Steel

The influence of tempering time on the microstructure and mechanical properties of ZG30CrMn2Si2Mo new type bainite cast steel were studied.The experiment results show that the microstructure of test cast steel is lath bainite and retained austenite at various tempering holding time.The strength,toughness and hardness of test steel increase until at tempering of 2 h.The toughness and hardness of test steel remain almost constant after tempering of 2 h,the strength remains almost constant after tempering of 3 h.With increasing the tempering time,the retained austenite decreases.The mechanical properties is not susceptibility to long time tempering.