Oxide Treatment of Tungsten Carbide Tools and Its Influence on Mass Diffusion and Tool Life

Abstract

The role of oxide layers on tungsten carbide tools in metal cutting was investigated using oxide-treated tools. It is shown that the structural change of the subsurface of the tool takes place due to mass diffusion between the oxide and the substrate, which enhances the metal cutting properties of tungsten carbide tools. The tools were coated with titanium dioxide and heated in a vacuum of 10−4 torr. These oxide-treated tools and the untreated tools were diffusion-bonded to steel in a vacuum so as to determine the influence of the oxide treatment on mass diffusion. The changes in the hardness of these bonded specimens were measured after maintaining them at high temperatures for various durations. The hardness across the interface of the bonding changed sharply in the case of the untreated tools, the hardness of steel increasing and that of tungsten carbide decreasing. In the case of the oxide-treated tools, the hardness did not change appreciably. Cutting experiments showed that the cutting force and the crater wear decreased by about 12 to 20 percent after the oxide treatment.