Influence of varied cryotreatment on the wear behavior of AISI D2 steel

Exploration of the benefit of cryotreatment for achieving improvement in wear resistance of die/tool steel is a topic of current research interest. A series of wear tests has been carried out on AISI D2 steel samples subjected to cryotreatment at 77 K for different durations. The wear rates at different loads and sliding velocities, morphologies of the worn-out surfaces and the characteristics of the wear debris have been systematically examined to assess the possible critical duration of cryotreatment to achieve the best wear resistance property. The wear experiments have been supplemented by detailed microstructural investigations with an emphasis to reveal the amount of retained austenite and the characteristics of the secondary carbide particles apart from hardness evaluation. The results unambiguously establish that 'critical time duration' exists for achieving the best wear resistance for AISI D2 steel through cryotreatment. This has been explained by the nature of precipitation of fine carbide particles and their possible growth, which govern the wear resistance of the material. Categorization of the secondary carbides to support this explanation is a new approach. The revelation of the wear mechanisms under different wear conditions is an integral part of this work.