Magnetic analysis and deep cryogenic treatment of 9Cr5MoV steel

SLX-80 cryogenic treatment system is used for cryogenic treatment of 9Cr5MoV steel,and room temperature magnetization of samples is performed in vibrating sample magnetometer option of physics property measurement system(PPMS-VSM).The contents of retained austenite in the samples quenched at 930 ℃,then cryogenic treated at-80 ℃ and-120 ℃ are respectively 13.5%,11.7% and 10.1%.Compared with cryogenic treatment at-80 ℃,deep cryogenic treatment at-120 ℃ is more effective to reduce the retained austenite in the steel.The maximum hardness of the steel quenched at 950 ℃ is measured to be 65 HRC,while further deep cryogenic treatment at-120 ℃ improves the hardness of steel to 66 HRC.After quenching at 950 ℃ and tempering at 140 ℃,the deep cryogenic treatment at-120 ℃ may enhance the hardness of steel approximately by 1 HRC.