An aluminum/chromium based coating film, called (Al,Cr)N coating film, has been developed. This coating film has a slightly more inferior critical scratch load and micro-hardness. Therefore, to improve both the scratch strength and micro-hardness of the (Al,Cr)N coating film, the cathode material of an alumi-num/chromium/tungsten target was used in adding the tungsten (W) to the cathode material of the alumi-num/chromium target. To clarify the effectiveness of the aluminum/chromium/tungsten-based coating film, we measured the thickness, micro-hardness and critical scratch strength of aluminum/chromium/tungsten-based coating film formed on the surface of a substrate of cemented carbide ISO K10 formed by the arc ion plating process. The hardened steel ASTM D2 was turned with the (Al,Cr,W)N, (Al,Cr,W)(C,N), (Al,Cr)N and the (Ti,Al)N coated cemented carbide tools. The tool wear of the coated cemented carbide tools was ex-perimentally investigated. The following results were obtained: (1) The micro-hardness of the (Al,Cr,W)N or (Al,Cr,W)(C,N), (Al,Cr)N coating film was 3110 HV0.25N or 3080 HV0.25N, respectively. (2) The critical scratch load of the (Al,Cr,W)(C,N) coating film was 123 N, which was much higher than that of the (Al,Cr)N or (Ti,Al)N coating film. (3) In cutting the hardened steel using (Al,Cr,W)(C,N) and (Ti,Al)N coated carbide tools, the wear progress of the (Al,Cr,W)(C,N) coated carbide tool was almost equivalent to that of the (Ti,Al)N coated carbide tool. The above results clarify that the aluminum/chromium/tungsten-based coating film, which is a new type of coating film, has both high hardness and good adhesive strength, and can be used as a coating film of WC-Co cemented carbide cutting tools.
Tool Wear of (Ti, W, Si)N Coated Cemented Carbide in Cutting Hardened Steel