Effect of Applied Voltage on Tool Wear in Cutting Nickel-base Superalloy

Abstract

The machinability of Nickel-based superalloy GH4169 is poor, in order to improve machining efficiency, reduce costs, it is necessary to study the various factors that affect the tool wear. In this paper.The tool wear tests were carried out to investigate the effect of an externally applied voltage on insert flank wear in turning of Ni-based superalloy GH4169 with coated carbide tool YBG202. Flank wear morphology was observed and the VB values were measured. The result showed that the applied voltage affected the tool wear obviously, When the insert was no externally voltage applied, the flank wear was least, when the insert was cathode, the flank wear was lower than when the insert was anode. The insert wear increased as applied voltage increased. The externally applied voltage accelerated the tool wear due to serious adhesive and abrasive wear, which leaded to the cutting efficiency decreased and cost increased, so it should try to avoid applied voltage when machining nickel-based superalloy. Introduction Nickel-based superalloy GH4169 is widely employed in the aerospace industry, in particular in the hot sections of gas turbine engines, due to their high-temperature strength and high corrosion resistance. As a kind of difficult-to-cut materials, the machinability of nickel-based superaloy are poor, especially the high cutting force and cutting temperature, short tool life and poor quality of the machined surface[1].In order to improve machining efficiency and reduce costs, it is necessary to study the factors that affect tool wear. As we all know, the additional current and voltage will be produced in cutting process, which affect the cutting process. A. Gangopadhyay [2-3]and Yamamoto[4] investigated the friction and wear behavior of a steel pair and milling process when an electric current was passed through the contact. It observed that friction and wear behavior of two components sliding against each other can be greatly influenced by an externally applied electrostatic field or electric current.Tool wear were reduced through an externally applied electric current in milling process with uncoated carbide milling inserts to machine AISI 4140 pre-heat treated steel. The objectives of this study were to investigate whether it can reduce the wear through an externally applied voltage in machining process. Therefore, in this paper, the effect of externally applied voltage on tool wear in cutting nickel-base superalloy was studied.The tool wear tests will be carry out. Cutting test Machine, Tool and Materials. The experiment was set up on a universal turning machine CA6140 with a vertical milling head, powered by a 7.5Kw electric motor giving a speed range of 10~1400rev/min and a feed range of 0.014~3.16mm/rev. The inserts is coated carbide tool YBG202 with MT-TiCN, A12O3 and TiN coated. The geometric parameters of tool are shown in Table 1. 4th International Conference on Machinery, Materials and Computing Technology (ICMMCT 2016) © 2016. The authors Published by Atlantis Press 1015 Table 1 Tool geometry parameterss γo αo κr κr’ λs αo' re 14° 6° 75° 15° -6° 6° 0.5mm Ni-based superalloy GH4169 is selected as workpiece material in the experiments. Cutting test was performed on precipitation with a bar. Chemical composition of the material is given in Table 2 and the physical and mechanical properties of GH4169 are shown in Table 3, respectively. Table 2 Chemical components of the materials used(Wt)% Ni Cr Nb Mo Ti C Al Si Mn 51.75 17.00 5.11 2.93 1.04 0.042 0.41 0.21 0.03 Table 3 Physical and mechanical properties of the materials used Yield strength σs(MPa) Tensile strength σb (MPa) Elongation δ(%) Cross-section contraction ratio φ(%) Hardness HBS 126