Effect of Work Material’s Hardness on Cutting Performance of TiAlN- and CrAlN-Coated Cutting Tools

Abstract

For better selection of coated cutting tools, TiAlN (Ti50Al50N) and CrAlN (Cr50Al50N) coatings were deposited onto ball-nose and square end mills using arc evaporation, and their cutting performances were evaluated using steel workpieces of various hardnesses. In particular, cutting tests were performed on three types of workpieces, made from S50C, SKD61, and SKD11 steels, having Brinell hardness numbers of HB220, HRC40, and HRC60, respectively. The results of the cutting experiments were elucidated and discussed in terms of the mechanical properties and anti-oxidation resistances of the different coatings. The results revealed that TiAlN-coated square end mills at high cutting speeds (V = 200 m/min ) had superior performance when used on steels with high hardness (SKD11), whereas CrAlN-coated ball-nose end mills were superior when used on low hardness steel (S50C). Therefore, CrAlN-coated ball-nose end mills are concluded to be suitable for the machining of low hardness steels, whereas TiAlN-coated square end mills are preferable for the machining of high hardness steels (SKD11).