Crater wear mechanisms of TiN coated high speed steel tools

This paper examines the crater wear characteristics of TiN coated high spee d steel tool inserts during dry turning of steel workpieces over a wide ran ge of machining conditions. Scanning electron microscopy shows that crackin g and attrition of the TiN coating on the rake face result in coating loss soon after machining begins. The subsequent wear of the exposed high speed steel substrate occurs via attrition, diffusion, and high temperature shear . A wear mechanism map linking the observed crater wear mechanisms to machi ning conditions reveals that transitions from one dominant mechanism to ano ther may be related to variations in measured tool wear rates.