超硬合金の耐摩耗性について

Abstract

The wear resistance of cemented carbide is usually estimated from the hardness, but it is often inadequate to interpret the practical problems only from the hardness. The present study dealt with the relations between the wear resistance and the properties of WC-Co sintered alloys which were prepared by varying the cobalt content, particle size of WC powder, small addition of TaC and sintering temperature.The wear resistance was measured from the flank wear land produced by the turning of cement-mortar, gray cast iron and carbon steel. Generally, as mentioned previously, the wear resistance increased with increasing hardness and coercive force or decreasing cobalt content and WC grain size of the alloys. The wear resistance increased linearly with decreasing WC grain size of the alloys in spite of the particle size of the WC powder used as raw material. However, the relations between hardness or coercive force and wear resistance were affected by the particle size of the WC powder; that is, both hardness and coercive force were the same, but the wear resistance of the alloys made of coarse WC powder was better than that of fine WC powder. Such a difference in wear resistance by the particle size of the WC powder was more remarkable in the turning of gray cast iron than that of cement-mortar. The effect of a small addition of TaC was observed in the turning of steel, but not in the turning of the cement-mortar or gray cast iron, and the effect of the grain size of the WC powder of the alloys was predominant in the latter.