Improving the mechanical and wear performance of AISI D2 steel with a cryogenic treatment

This research investigated the effect of cryogenic treatment on the notch impact strength, wear behaviour, microstructure, and hardness of AISI D2 steels. The study aimed to determine the impact of chemical composition and cryogenic treatment process on the material's mechanical properties. The samples prepared in the research were subjected to cryogenic treatment four times (12-48 hours) at -145°C and -196°C after heat treatment to achieve the desired mechanical improvement. Afterward, the specimens were tempered for an hour at two different temperatures, 200°C and 520°C. After cryogenic treatment, microhardness, microstructural investigations, wear, and notch impact tests were conducted and compared with the untreated material. Under optimum conditions, the cryogenic treatment caused a maximum increase of 4% in the microhardness of AISI D2 steels. After notch impact tests, the fracture energy of the material decreased at different rates in all groups except for the tempered sample with a holding time of 12 hours. Following cryogenic treatment at -196°C for 12 hours and then tempering at 520°C for 1 hour, the wear resistance of specimen D11 increased by up to 88%.