Answer to Question #160464 in Mechanical Engineering for Vinesdaren

Question

In a milling process of Inconel 718, which one is the cutting temperature, cutting tool temperature or workpiece temperature? Any evidence to prove this?

Answer 1

Physical Vapor Deposition (PVD) Ti1-xAl x N coated cemented carbide tools are commonly used to cut difficult-to-machine super alloy of Inconel 718. The Al concentration x of Ti1-xAl x N coating can affect the coating microstructure, mechanical and thermo-physical properties of Ti1-xAl x N 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-xAl x N 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-xAl x N coated cemented carbide tools and the Inconel 718 material. The coating hardness and thermal conductivity of Ti1-xAl x N coatings increased with the increase of Al concentration x. Thirdly, the influences of PVD Ti1-xAl x N 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-xAl x N coatings on surface morphologies of the tool rake faces were analyzed. The conclusions can reveal the influences of PVD Ti1-xAl x N coatings on cutting temperature, which can provide guidance in the proper choice of Al concentration x for PVD Ti1-xAl x N coated tools in turning Inconel 718.