Abrasive wear behavior and mechanism of high chromium cast iron

The abrasive wear behavior of high chromium cast iron (containing 12.9 mass% chromium) austenitized at 1050 °C for 2 h and austempered in salt bath at 320 °C for 4 h was evaluated. Abrasive wear was performed using alumina abrasive under four different loads, namely 50, 100, 150, and 200 N, for 36000 cycles. The worn surfaces and wear debris were analyzed by scanning electron microscopy, laser confocal microscopy and X-ray diffraction. Micro-hardness profiles were also obtained in order to analyze the strain-hardening effects beneath the contact surfaces. Results indicate that the retained austenite in high chromium cast iron has experienced induced martensitic transformation after tests, for small amounts of retained austenite could be detected by X-ray diffraction. In addition, there is a close relationship between wear mechanism and test load. Under the condition of lower test load, the wear mechanism is an uninterrupted and repeated process, during which matrix is cut at first and then fine carbides flake off. As to higher test load, scratching and spalling induced by cleavage fracture of blocky carbide are the wear mechanism.