Study on the cutting performance of AlTiN/AlTiSiN composite coating tool in deep-hole pull boring tool of GH4169

As one kind of difficult-to-cut material, when deep-hole machining Nickel-based superalloy GH4169, there are server adhesive wear, poor tool wear resistance and multiple surface defects, which limits its improvement of processing efficiency and processing quality. The comparative studies on the tool wear mechanism and the workpiece surface morphology characteristic are carried out during deep-hole pull boring GH4169 with AlCrN and AlTiN/ AlTiSiN composite coating tool. The results show that the flank and rake wear is mainly adhesive wear and abrasive wear, accompanied by coating shedding, micro-tipping, built-up edge and burn blackening. Compared with AlCrN, the AlTiN/ AlTiSiN composite coating tool has better wear resistance and slight adhesive wear. With the increase of feeding speed and boring depth, it is more likely to produce the built-up edges on the rake face and occur the vibration wrinkles on the flank face. But there is the smaller scale of the narrow wear groove mark on the minor flank face at a higher feed speed. Feed groove marks, material adhesion, rolling traces and the surface defects such as pits and micro-hole are the main features of the machined inner surface. Within the range of boring deepth 50 mm∼1060 mm, the machined surface roughness basically fluctuates between 1.130 µm and 1.940 µm which is smaller at the initial cutting edge. The higher the feed speed, the larger scale of the residual feed marks, and the rougher the machined surface of inner hole.