Indian Journal of Science and Technology

Abstract

Objectives: Deep cryogenic treatment is a one-time, permanent treatment affecting the entire part and not just the surface alone. Cryo treatment changes metals as a result of the martensitic transformation of retained austenite. Methods/ Statistical Analysis: Conventional Heat treatment and Cryo treatment are selected. The cryogenic fluid used here is nitrogen. An attempt is made to study the property changes mainly dwelling on the hardness of the high-speed steels before and after the Cryo treatment. Comparative studies made by modifying the quenching media oil, water and cryogenic media. Findings: The Cryo treatment using liquid nitrogen has shown the profound increase in the hardness of the tool steel materials. Moreover, by use of cryogenic treatment, multi-tempering could be avoided. From the optical microscopy studies, the actual component responsible hardness i.e. martensite is seen clearly in all the three samples but differs in the percentage of martensite content. Application/Improvements: Life of the cutting tools in the lathe, the milling and drilling will be enhanced.

Keywords: Cryogenic Treatment, Hardness, High-Speed Steels, Tempering, Tool Steels