Tool wear is a worn portion over the flank and face of the tool. Tool wear is significant for determining tool life and hence it influences the machining economics. The wear measurements are carried by using a tool makers microscope in the present investigations. All the investigations are carried out using cutting fluid. Life enhancement by using cryogenic treatment on HSS is the objective of study. Investigations are carried on different work materials such as AISI 1040, EN8 and EN24. Improvement in tool life up to 90% is observed for soft material AISI 1040 and enhancement up to 39% is observed on EN24. These investigations are aimed at benefiting small industries that use aforementioned tool work combinations. Regression models are constructed for tool wear for both untreated machining and cryogenic treated machining. To understand the effects of cryogenic processing, it is essential to get acquainted with the heat treating of metals. The primary reason for heat treating steel is to improve its wear resistance through hardening. Gears, bearings and tooling for example are hardened because they need excellent wear resistance, improved fatigue life, stress relieving dimensional stability and corrosion resistance for extended reliability and performance. The steps in heat-treating are frequently explained in a simplistic manner but it takes significant skill and experience to execute heat treatments successfully. The steel tooling in practice would be immersed in liquid nitrogen for a period of time, allowed to warm up and then placed into service. It was also observed that the cryogenic treatment would convert the retained austenite into un-tempered martensite. The tools would experience a greatly enhanced service life. It was theorized that the increase in wear resistance was a direct result of the reduction in the amount of residual austenite. Liquid nitrogen systems have been the customary method for achieving cryogenic temperatures. Three types of systems have been developed viz heat exchanger systems, direct spray systems, and immersion systems. The last method i.e immersion system is used in present investigation. The tool wear can be measured directly by using a microscope. However several indirect methods depending on the measurement of a parameter that influence the tool wear do exist. Some of the methods for indirect prediction are cutting force, vibrations, acoustics, radioactive isotopes, image processing etc. It should be noted that no method is accurate for indirect prediction. Studies by Penn State University researchers in 1996 showed that retained austenite was reduced from near 18% to roughly 8% in T15 tool steel upon cryogenic treatment. Hardness increased by 2 points (HRC) with cryogenic treatment and
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