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

Abstract

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 the same composition. Spray forming resulted in a substantial reduction in microstructural scale (eutectic (Cr,Fe) 7C 3 fields of up to 500 μm in conventionally cast material were replaced by discrete carbides of typically 2–8 μm diameter in the spray cast deposit). Wear testing was undertaken in the rolling/sliding configuration (8% slippage) at 300 N against a tool steel counterface in the temperature range 20–700°C. The wear rate of the conventional material was significantly higher than the spray cast material when tested at 20–500°C. At 600 and 700°C, the wear rate was similar, but gross microstructural changes had occurred in the matrix of both materials induced by the high temperatures. At all test temperatures, carbide cracking extended to much greater depths below the worn surface of the conventionally cast (e.g., 150 μm at 700°C) compared with the spray cast (∼55 μm at 700°C). Similarly, the depth of deformation was greater in the conventionally cast iron compared with the spray cast material. The relationship between microstructure and wear mechanisms is discussed.