Machinibility of AISI 420 stainless steel depending on cutting tool and coating

This study aims to investigate the machinability of martensitic stainless steel AISI 420 which prefers by defence industry because of its corrosion, heat resistance and its visiuality. The influence of cutting speed (Vc) and tool nose radius on surface roughness were analyzed and the effect of coating on tool wear was examined. These experimental results gave lots of information about the materials machinability. In this research, AISI 420 experiment materials were turned by computer numerically controlled (CNC) millturn machine with coated carbide tools. The tools had different coatings and nose radius. Surface roughness measured with Lombardore tl70 Alpa perthometer. Tool wears analyzed with Nikon TS2-S-SM microscope. Through the analysis of the results in the present work, the nose radius was identified as the most significant parameter. Surface quality was absolutely better with larger nose radius 0,8 mm than 0,4 mm. Also increasing of the cutting speed had positive effect on surface quality. Microscope analyze results showed that Ti(CN) +Al2O3+TiN coated tools with CVD method had better tool wear resistance than AL2O3+TiCN coated ones.