Investigação da aplicabilidade de insertos de metal duro revestidos no torneamento da liga Ti-15Mo

Abstract

The low density and high corrosion and fatigue resistance of titanium alloys favor their use in the aerospace, medical implant and orthodontic industries. However, their machining is a hallenging process due to their low thermal conductivity, low modulus of elasticity and chemical affinity with the tool material. High temperatures are generated in the cutting region, damaging surface finish and reducing tool life. In an attempt to overcome these difficulties, new machining techniques have been developed, such as the use of new lubricants and the pplication of different tool coatings. Within this context, this research proposes a comparative analysis of the performance of uncoated inserts and inserts with three types of coatings (AlTiN/TiSiXN, AlCrN and TiCN), in order to determine the most suitable for the turning process of the Ti-15Mo alloy. For this purpose, cemented tungsten carbide inserts ISO grade S10 were ground in laboratory, commercially coated by physical vapor deposition (PVD) and subjected to life tests, after which the main wear mechanisms were evaluated. In terms of tool wear, the least satisfactory results were found for the AlTiN/TiSiXN coated inserts, while the most satisfactory were verified for the AlCrN coated inserts. In all cases, adhesion was the predominant wear mechanism and similar roughness values were obtained, indicating that the application of coating without titanium can increase tool performance.