EFFECT OF DEEP CRYOGENIC TREATMENT ON CARBIDES PRECIPITATION KINETICS DURING TEMPERING OF THE X37CRMOV5-1 HOT WORKING TOOL STEEL

摘要

Unlike conventional cold treatment, which is commonly used for elimination of retained austenite, deep cryogenic treatment primarily improves the wear resistance of tools. According to many scientific publications this effect arises probably due to precipitation of a large volume of fine carbides during tempering immediately after deep cryogenic treatment. However, the physical background of this was not explained completely yet. The article describes results of dilatometric measurements performed on specimens of X37CrMoV5-1 hot working tool steel. The aim of the dilatometric analysis was to describe the kinetics of carbides precipitation precisely. One group of specimens underwent conventional hardening (oil quenching), while on the other groups two different regimes of deep cryogenic treatment were applied immediately after quenching. All specimens were finally tempered in a dilatometer and dilatations during tempering were measured. The results show significant differences in precipitation kinetics between specimens after conventional hardening and specimens after deep cryogenic treatment.