INFLUENCE OF RETAINED AUSTENITE ON THE WEAR-RESISTANCE OF HIGH CHROMIUM CAST-IRON UNDER VARIOUS IMPACT LOADS

A high chromium cast iron was heated and maintained at 980-degrees-C, and then cooled in five media of different temperatures to obtain various amounts of retained austenite (designated Ar). The specimens were subjected to impact wear tests under impact loads ranging from 1 to 6.2 J. The number of impacts was 6000 for each test. The results showed that (1) the influence of Ar on the impact wear resistance of high chromium cast iron depended on the magnitude of the impact load and wear mechanism. (2) Under a small impact load the mechanism was mainly cutting wear and Ar has no significant effect on impact wear resistance. (3) Under heavy impact load the mechanism was mainly impact fatigue wear and Ar exhibited a harmful effect on the impact wear resistance of the iron.