Incorporating bulk microstructural and surface properties to predict the performance of high chromium cast irons – indentation behaviour and wear performance

Abstract

This study investigates the indentation behaviour and wear performance of two hypoeutectic high chromium cast iron alloys with 16 % and 26 % chromium. Indentations were performed using an alumina spherical ball at various loads, and the resulting contact radii (ranging from ∼30 μm to 50 μm) were compared with Hertzian predictions. A novel methodology using image segmentation was developed to estimate bulk mechanical properties using local phase distribution. Plasticity index calculations, incorporating both matrix and carbide surface characteristics, yielded comparable values (∼29) for both alloys, indicating similar elastic-plastic contact responses despite differences in carbide size and volume fraction. Abbott-Firestone curve analysis revealed that 26 % Cr alloy exhibited slightly higher bearing capacity at shallow depths. Subsequent wear tests showed that under low load conditions (5 N), the 26 % Cr alloy exhibited lower wear rates compared to the 16 % Cr alloy. However, at 20 N, the difference falls within the standard deviation, suggesting that both alloys perform similarly under high-load wear.