Investigation of wear behavior for large pulsed electron beam irradiated cutting tools under the turning process of Ti-6Al-4V

Abstract

In this paper, a large pulsed electron beam (LPEB) was irradiated on the uncoated tungsten carbide cutting tool to enhance the tool life. The electron beam was transmitted on the rake face, flank face, and rake & flank face which refers to the shot on rake (SoR) condition, shot on flank (SoF) condition, and shot on both (SoB) condition, respectively. The characteristics of the cutting tool such as the morphology of the tool surface, surface roughness, and edge roundness were evaluated depending on the electron beam irradiation conditions. The micro-thermal cracking was observed on the SoR condition and SoF condition due to the focused energy transmission on a single area of the cutting tool, on the other hand, the uniform irradiation energy of the electron beam generated the smooth surface for the SoB condition. In addition, the edge roundness was the largest in the SoR condition because the melted tool material flows in the direction of the cutting edges orthogonally during the electron beam irradiation. These characteristics of the LPEB irradiated cutting tool were reflected in the machining process, and various wear behaviors were investigated in terms of a built-up edge (BUE), adhesion, chipping, tool breakage, flank wear, and crater wear. The severe wear behavior was observed in the untreated condition as confirmed by a micro-welded surface, catastrophic tool failure, and chipping. Specifically, the lowest wear behavior was observed with the irradiated electron beam on the rake & flank face of the cutting tool; the flank wear and crater wear were reduced up to 37.3 % and 71.9 %, respectively compared to the untreated condition, and critical wear behavior was not developed due to the low surface roughness, increased edge roundness, and the hardened surface of the cutting tool.