Evaluation of the Influence of Tool Coatings on the Machinability of the Ti6Al4V Alloy Using Gray Relational Analysis.

The article presents the research on turning the titanium alloy Ti6Al4V with uncoated carbide blades and physically coated with PVD and chemically CVD. By examining the processed surfaces using the contact method, it was found that the chemically applied coating allows one to obtain the best 3D roughness. Using finishing cutting parameters and CVD-coated blades, it is possible to obtain a surface with a roughness of Sq at the level of 0.7 μm and Sz 2 μm. Cutting force tests have shown that applying coatings to the cutting blade increases the total cutting force by approximately 20%. Additionally, on the basis of microscopic observations, it was found that thermal and adhesive wear occurs on the surfaces of coated blades. Tool coatings have no influence on the shape of the chips produced. The grey relational analysis performed showed that the best turning results for the Ti6Al4V alloy are obtained when using an uncoated HX insert with a feed of 0.08 mm/rev and a cutting speed of 70 m/min. The results of this analysis also indicate that the tested blades, which are not recommended for the machining of superalloys, should not be used to turn the Ti6Al4V alloy. [ABSTRACT FROM AUTHOR]