High-temperature oxidation wear performance and mechanism of Cr-Mo (W)-V hot-work die steel

Dry sliding tests for Cr-Mo (W)-V hot-work die steels were performed at 400-700 degrees C using a UMT-3 wear tester. The wear behavior was studied systematically to explore the general characteristics under high-temperature oxidation conditions. When a mild-to-severe oxidation wear transition occurred, the wear rate of the Cr-Mo (W)-V hot-work die steels could be divided into different stages. The wear rate in stage I remained low and increased continuously with increasing temperature in stage II. It decreased within a narrow temperature range in stage III and increased significantly at a high test temperature in stage IV. The microstructures of DM, H21, and H13 steels at 350 HV30 were observed in stage III, and the M C-2 carbides were extensively analyzed. Furthermore, by examining the continuous heating transformation curves, the decrease in the wear rate in stage III was qualitatively confirmed, depending on the transformation of the M C-2 carbides.