Influences of coating thickness on cutting temperature for dry hard turning Inconel 718 with PVD TiAlN coated carbide tools in initial tool wear stage

摘要

High cutting temperatures are induced in the dry cutting process of Inconel 718 for its high hardness 439 HBW and low thermal conductivity 13.4 W/(m K). Due to its thermal barrier effect and antifriction effect, the TiAlN coatings have been deposited on carbide tools with various coating thicknesses for dry turning Inconel 718. However, the influences of TiAlN coating thickness on cutting temperature of dry turning Inconel 718 were not investigated in details. In this research, PVD TiAlN tools with coating thickness 1 mu m and 2 mu m were fabricated and characterized. The cutting temperatures and cutting forces of dry turning Inconel 718 were measured within cutting speed ranges 30-120 m/min. Average friction coefficient at coated tool-chip interface was calculated to analyze the coating antifriction effect. Thicker coating induced large temperature increment of 19-30 degrees C compared with thinner coating within cutting speed ranges of 30-120 m/min in initial tool wear stage. The results showed that PVD TiAlN coated tool with coating thickness 1 mu m was more suitable for dry turning Inconel 718 within cutting speed ranges 90-120 m/min by obtaining better coating antifriction effect and lower cutting temperature.