Research on wear modes and mechanism of carbide tools in high-speed milling of difficult-to-cut materials

High-speed dry face-milling tests were conducted for difficult-to-cut ultra high strength alloy with σ_b > 1.4 GPa and hardness 50HRC and martenstic stainless steel with hardness 30HRC, using (Ti,Al)N coated carbide tool and fine grain carbide tool, respectively, on a DMU-70 evolution 5-axle processing center. The morphologies of the worn fake faces of the cutting tools at different cutting conditions were observed using a scanning electron microscope, while the elemental compositions in the central worn area were determined using an energy dispersive spectrometer, which were aiming at revealing the wear mechanisms of the cutting tools and examining the cutting performance and lives of the cutting tools. It was found that the carbide tools were dominated by rake face abrasive wear, adhesion wear, diffusion wear, and chemical wear, in cutting the difficult-to-cut materials at high-speed, which were accompanied by the spalling of the coating on the rake face to expose the carbide substrate and the chippings of the cutting edges. The (Ti,Al)N coated carbide tool with a higher Al content in the coating had better cutting performance, and it was imperative to introduce proper reinforcing for the fine grain carbide tool so as to reduce its micro-chipping at the initial wear stage.