Experimental Investigation on Deep Cryogenic Treatment of Tool Steel

Abstract

Deep cryogenic treatment is permanent-effect process. It is carried out on steel components so that the material is cooled slowly to the cryogenic temperature. It is held at cryogenic temperature for a specified period of time and then brought back to room temperature at a slow rate, followed by low-temperature tempering. The HSS taper shank twist drill (grade M2) was chosen for shop-floor testing as well as metallurgical investigation and cryotreated at 77 K for different soaking periods (18 – 24 hrs) have been examined with respect to their micro-structural. The shop-floor test indicates an increase in the life of a tool cryotreated with 24 hrs soaking was nearly 301% and decrease in the wear rate was about 56% compared with the control. Metallurgical investigation showed no significant improvement in hardness following cryogenic treatment, but an increase in carbide precipitation by 63% and a 42% reduction in wear rate when compared with the control.