Deep cryogenic treatment of AISI M2 high-speed steel

摘要

The influence of Deep Cryogenic Treatment (DCT) on the properties of AISI-M2 is evaluated. Hardness, (apparent) fracture toughness and wear resistance were measured after submitting this steel to conventional vacuum heat treatment, including quenching and triple tempering and three variants including DCT before and after tempering. In any case, only minor differences in hardness and a corresponding increase in fracture toughness were introduced by DCT, even after tempering the steel at temperature lower than conventional. Tempering could be optimised if DCT was carried out after quenching, owing to a shift of the secondary peak hardness towards lower temperature. A reduction of the wear rate of 32% was displayed by the specimen cryogenically treated before conventional triple tempering. A further reduction to 49% was observed by lowering the tempering temperature.