Effect of deep cryogenic treatment on microstructure and wear resistance of 100Cr6 low alloy steel

Deep cryogenic heat treatment is vastly used in recent years due to its effect in the hardness and wear resistance improvement of tools and is commonly performed before tempering and after quenching. In this study the samples were austenized at 920 and 850 for 20 and 80 minutes followed by the deep cryogenic heat treatment at -195 for 24 hours. The samples were then analyzed via optical microscope (OM) and scanning electron microscope (SEM) to study the microstructure and wear and hardness testing machine to investigate the effect of austenizing temperature and time on the deep cryogenic behavior of 100Cr6 steel samples. Results show that deep cryogenic heat treatment improves the hardness and wear behavior of samples due to retained austenite elimination as well as increasing the precipitated carbides. The highest value of hardness and wear resistance belongs to the samples austenized at 920 for 20 minutes. The wear mechanism was a combination of abrasive and tribo-chemical wear.