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

Abstract

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: 67μm, 149μm and 177μm and two applied normal load: 5N and 10N. A modified rubber wheel abrasion test (ASTM G65) was carried out using three abrasive average sizes - 90μm, 115μm and 170μm quartz sand - and three applied normal loads: 44N, 80N and 130N. 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 5N to 10N. 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.