The rolling/sliding wear response of conventionally processed and spray formed high chromium content cast iron at ambient and elevated temperature

The effect of spray forming on the wear properties of a 17% Cr 2.5% C white cast iron is described and compared with conventionally cast material of t he same composition. Spray forming resulted in a substantial reduction in m icrostructural scale (eutectic (Cr,Fe),C, fields of up to 500 mu m in conve ntionally cast material were replaced by discrete carbides of typically 2-8 mu m diameter in the spray cast deposit). Wear testing was undertaken in t he rolling/sliding configuration (8% slippage) at 300 N against a tool stee l counterface in the temperature range 20-700 degrees C. The wear rate of t he conventional material was significantly higher than the spray cast mater ial when tested at 20-500 degrees C. At 600 and 700 degrees C, the wear rat e was similar, but gross microstructural changes had occurred in the matrix of both materials induced by the high temperatures. At all test temperatur es, carbide cracking extended to much greater depths below the worn surface of the conventionally cast (e.g., 150 mu m at 700 degrees C) compared with the spray cast (similar to 55 mu m at 700 degrees C). Similarly, the depth of deformation was greater in the conventionally cast iron compared with t he spray cast material. The relationship between microstructure and wear me chanisms is discussed. (C) 1999 Published by Elsevier Science S.A. All righ ts reserved.