Effects of Cryogenic Treatment on AHPT15M Powder Metallurgy High Speed Steel

This article studies the cryogenic treatment process of AHPT15M powder metallurgy high speed steel,and analyses the effects of cryogenic treatment process parameters on the mechanical properties and the retained austenite content,and observes microstructure with or without cryogenic treatment by the SEM.The results show that a finer needle-like martensite microstructure formes after cryogenic treatment,and the residual austenite content decreases with ultrafine carbide precipitation,thereby the hardness and wear resistance increases.The suitable cryogenic treatment process as follows:quenching + cryogenic treatment + tempering twice;the cryogenic treatment temperature is-130~-150 ℃,and holding time is long enough to make the steel cold throughtly.