Research on tool stick-slip erosion wear mechanism in cutting nickel-based alloy GH4169

Abstract

Nickel-based superalloys GH4169 are typical hard-to-machine materials. It can still maintain high strength and hardness at high temperatures, so the tools for cutting nickel-based superalloys are worn seriously. In this paper, the tool wear mechanism when cutting nickel-based superalloy using YG8 (K-type cemented carbide tool) is studied. The stick-slip erosion wear mechanism of cutting tool is put forward in this paper. At high temperature, micro plastic deformation and macro sliding occurs when the chip slides against the tool surface, resulting in wear similar to that of a viscous liquid when it erodes a solid. Erosion wear has a latent period. The faster the cutting speed, the worse the wear is. When chip stick-slip erodes the tool, two adiabatic zones are generated. One is the adiabatic impact zone I generated on the front surface of the tool. The other is the adiabatic shear band II formed under chip compression. The adiabatic impact zone I causes the temperature of tool surface to rise sharply. After high-temperature erosion, the surface of the cutting tool exhibits wear patterns such as lips, pits, layers, and furrows. Among them, the lips are a typical morphology of erosion wear, but the quantity is relatively small. Pits and layers are the main morphological features after erosion wear. The main reason for the above characteristics is that GH4169 has a small deformation coefficient and weak chip deformation ability. Therefore, most lips are impacted and sheared by micro-convex bodies, ultimately leaving pits on the tool surface. In addition, when a portion of the lip has not yet formed, the fracture of the cell boundary cracks in the adiabatic shear zone leads to the occurrence of lamellar detachment, leaving a lamellar damaged surface.