Crater wear mechanisms of tin coated high speed steel tools

This paper examines the crater wear characteristics of TiN coated high speed steel tool inserts during dry turning of steel workpieces over a wide range of machining conditions. Scanning electron microscopy shows that cracking 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 machining conditions reveals that transitions from one dominant mechanism to another may be related to variations in measured tool wear rates.