Abrasion resistance of high Cr cast irons at an elevated temperature

A novel wear tester was employed to investigate the comparative abrasive stability of metallic materials at elevated temperatures. This tester consists of a symmetric π-shaped specimen holder that is rotated in a stainless steel tank filled with quartz sand, and an electrical furnace surrounds this tank to heat the abrasive sand. The test material and its comparative, of a size of 20 mm×20 mm×5 mm, were set in the respective branches of the holder. During the atmospheric condition experiment, only one 20 mm×20 mm face of each specimen was suffered with abrasion, while the other faces which were mounted in the holder were oxidized. Then the volume loss of the specimens can be accurately calculated with the aid of additional oxidation experiments, and by choosing the same comparative material the abrasive stability of different materials can be compared. A newly developed high Cr cast iron 4.5C–40Cr–8Ni–9Nb–5Mo was employed as the test alloy, while the comparative was the widely used 25Cr cast iron (Fe–25Cr–2.9C–0.5Ni–0.5Mo). The results show that, at the temperature of 925 K, the test alloy exhibited a superior abrasive stability to the 25Cr alloy; the average wear rate of the former was only about 36% of that of the latter.