Abrasive wear resistance and microstructural characteristics of heat treated high chromium white cast iron

This study investigates the microstructure, hardness, and abrasive wear resistance of hypereutectic high-chromium white cast iron (3.76 wt.% C, 0.87 wt.% Si, 0.85 wt.% Mn, 17.36 wt.% Cr, 2.01 wt.% Mo and 0.53 wt.% Ni) under different heat treatment conditions. The as-cast microstructure consists of primary (Fe,Cr) 7 C 3 carbides in an retained austenite and martensite matrix. Increasing the austenitizing temperature from 970 °C to 1100 °C promotes greater carbide dissolution, enriching the austenite with carbon and chromium, which lowers the Ms temperature and increases retained austenite content approximately with 20%. Quenching from 970 °C followed by tempering at 450–550 °C yields maximum hardness of 62–63 HRC, while quenching from 1100 °C followed by tempering at 550–600 °C induces secondary hardening through retained austenite transformation and precipitation of fine M 2 3 C 6 carbides. The optimal heat treatment regime is austenitization at 1100 °C and tempering at 600 °C, it provides the best abrasive wear performance, reducing the wear rate to V = 9.467 × 10 –6 g·m –1 and increasing wear resistance to E = 105634 m·g –1 , representing a 33% improvement compared to the as-cast condition. The enhanced wear resistance is attributed to the combined effect of tempered martensite, primary M 7 C 3 carbides, finely dispersed secondary carbides, and the transformation of retained austenite during abrasion.