Performance of PVD TiN/TaN and TiN/NbN superlattice coated cemented carbide tools in stainless steel machining

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.

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Investigation of Cutting Temperature during Turning Inconel 718 with (Ti,Al)N PVD Coated Cemented Carbide Tools

Materials ◽

10.3390/ma11081281 ◽

2018 ◽

Vol 11 (8) ◽

pp. 1281 ◽

Cited By ~ 8

Author(s):

Jinfu Zhao ◽

Zhanqiang Liu ◽

Qi Shen ◽

Bing Wang ◽

Qingqing Wang

Keyword(s):

Physical Properties ◽

Inconel 718 ◽

Great Influence ◽

Cutting Temperature ◽

Cemented Carbide ◽

Machining Process ◽

Coated Tools ◽

Cemented Carbide Tools ◽

Coated Cemented Carbide ◽

Thermo Physical Properties

Physical Vapor Deposition (PVD) Ti1−xAlxN coated cemented carbide tools are commonly used to cut difficult-to-machine super alloy of Inconel 718. The Al concentration x of Ti1−xAlxN coating can affect the coating microstructure, mechanical and thermo-physical properties of Ti1−xAlxN coating, which affects the cutting temperature in the machining process. Cutting temperature has great influence on the tool life and the machined surface quality. In this study, the influences of PVD (Ti,Al)N coated cemented carbide tools on the cutting temperature were analyzed. Firstly, the microstructures of PVD Ti0.41Al0.59N and Ti0.55Al0.45N coatings were inspected. The increase of Al concentration x enhanced the crystallinity of PVD Ti1−xAlxN coatings without epitaxy growth of TiAlN crystals. Secondly, the mechanical and thermo-physical properties of PVD Ti0.41Al0.59N and Ti0.55Al0.45N coated tools were analyzed. The pinning effects of coating increased with the increasing of Al concentration x, which can decrease the friction coefficient between the PVD Ti1−xAlxN coated cemented carbide tools and the Inconel 718 material. The coating hardness and thermal conductivity of Ti1−xAlxN coatings increased with the increase of Al concentration x. Thirdly, the influences of PVD Ti1−xAlxN coated tools on the cutting temperature in turning Inconel 718 were analyzed by mathematical analysis modelling and Lagrange simulation methods. Compared with the uncoated tools, PVD Ti0.41Al0.59N coated tools decreased the heat generation as well as the tool temperature to reduce the thermal stress generated within the tools. Lastly, the influences of Ti1−xAlxN coatings on surface morphologies of the tool rake faces were analyzed. The conclusions can reveal the influences of PVD Ti1−xAlxN coatings on cutting temperature, which can provide guidance in the proper choice of Al concentration x for PVD Ti1−xAlxN coated tools in turning Inconel 718.

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