Abrasive size and load effects on the wear of a 19.9% chromium and 2.9% carbon cast iron

- A methodology for construction an abrasive wear map for a martensitic high chromium cast iron is proposed.
- A wear map was built, summarizing wear rates and wear mechanisms resulting from different testing methods and conditions.
- In both type of wear tests, increases in the abrasive grain size and in the normal load caused increases in the wear rates.

The effects of applied loads and abrasive sizes on the wear of a 2.9% carbon and 19.9% chromium martensitic white cast iron were investigated. Abrasive wear tests using a pin test on silica and garnet papers (ASTM G132) were carried out using three different abrasive average sizes: 67 μm, 149 μm and 177 μm and two applied normal load: 5 N and 10 N. A modified rubber wheel abrasion test (ASTM G65) was carried out using three abrasive average sizes - 90 μm, 115 μm and 170 μm quartz sand - and three applied normal loads: 44 N, 80 N and 130 N. The abrasive shape and the wear surface of the specimens were examined using a scanning electron microscope (SEM). The worn surfaces topography was obtained with a Taylor Hobson 3-D surface analyser. In the pin test with silica paper, a change in the magnitude of the volume loss was observed as a result of increasing the applied load from 5 N to 10 N. In the rubber wheel abrasion tests the mass loss increased with the increase of particle size until a critical particle size was reached. In general, the mass loss increased with the increase of the applied load and the abrasive size. For the lower load and the smallest abrasive size wear grooves were observed only in the martensitic matrix while the carbides remained intact. With higher loads and larger abrasives, scratching was observed also in the carbides. A wear map is proposed with a 'wear rate' parameter developed in this work plotted against abrasive sizes.