High Speed Turning Of Nickel-based Alloys

Nickel-based alloy is one of the most difficult-to-machine materials because of hard particle, low thermal conductivity. How to improve the machinability of nickel-based alloy is a very urgent problem in aircraft, spacecraft and other manufacturing industries.The experimental research on high-speed turning of Nickel-based alloy GH4169, has been carried out in the current investigation.The ceramic tools were used in rough machining of GH4169. Cutting parameters and cooling/lubrication conditions were optimized. Then empirical equation of tool life was established. The result indicated that round ceramic tool KY4300 showed the longest tool life in the same cutting condition. Then the ceramic tool and cemented carbide tool were used in finishing machining of GH4169. The surface roughness produced with different cutting parameters and in cooling/lubrication conditions was compared.The thorough investigation was made on the tool wear form and wear mechanism in high-speed cutting. The major wear mechanisms were abrasive wear, adhesive wear, micro-breakout, peeling and diffusion wear.The formation of notch wear in high-speed cutting of GH4169 with ceramic tool was studied. It was proved that the location of notch wear was out of the theoretical cutting area, and it was suggested that it is the high frequency impact of the saw-tooth-shaped burr and serrated chip edge at the position of notch wear that caused the serious notch wear. The shape of serrated chip edge was uniform and short in higher speed while it was non-uniform in lower speed. The notch wear was more serious under higher speed compared to that of lower speed. Surprisingly, peeling was more serious under lower speed.