Investigating the wear resistance of high-chromium cast irons A532-class III-type A against high-energy abrasive particles

Abstract

Regarding the widespread use of high chromium cast irons in manufacturing various industrial and mineral-processing parts such as liners, slurry pumps, and grinding balls, increasing erosion resistance is the key factor to enhance their performance. This research investigated three different chemical compositions of high chromium irons (in the eutectic and hypoeutectic range). Austenite destabilization process was conducted at two temperatures of 1060°C and 970°C followed by air cooling and then tempering at the range of 250°C to 400°C for 4 h. Erosion and bending tests were carried out on samples with optimal heat treatment conditions. Results show that the hardness of specimens heat-treated at 970°C, and also the low-carbon hypoeutectic specimens destabilized at 1060°C, increased by increasing tempering temperature over 300°C, which can be related to the formation of a higher volume fraction of M23C6 carbides. The best erosion resistance was observed in the low-carbon hypoeutectic specimen destabilized at 1060°C and tempered at 300°C. In addition, samples with higher erosion resistance exhibit lower bending strength. Finally, it was found that the principal wear mechanism was the occurrence of plastic deformation, and detachment of carbides from the surface before having an effective role in reducing wear.