Heat Treatment of Cr26 High Chromium Cast Iron for Furnace Liner

The orthogonal test was employed to the analysis of effects of quenching temperature, quenching soaking time, tempering temperature on the microstructure and mechanical properties of Cr26 high chromium cast iron and the three parameters were optimized. The results show that, as the quenching temperature increased, the quenching hardness gets higher; however, as the quenching soaking time prolonged, the quenching hardness presents a trend of rise first then fall. The effect of the three factors on mechanical properties of Cr26 high chromium cast iron after heat treatment is quenching temperaturetempering temperaturequenching soaking time. The optimum heat treatment was quenching at 1 000 ℃×2 h, strong wind cooling + tempering at 260 ℃×2 h, air cooling. While the hardness of the cast iron can reach HRC 59.5 and the impact toughness 8.0 J·cm-2, and the corresponding microstructure consists of martensite, M7C3 carbide, secondary carbide and retained austenite.