Tool life and wear mechanisms of TiN coated tools in an intermittent cutting operation

A P20-30 PVD TiN coated cemented carbide inserts with sharp edges were used to perform an external right hand thread cutting operation on two grades of steel up to a cutting speed and feed rate of 225 m min−1 and 0.44 mm rev−1, respectively. The test results show that cutting speed and feed rate had the most significant influence on tool life. A V-shape type of wear along the nose region of the tool face with adhering flake-like oxide debris and micro/macro-chipping are the dominant failure modes while abrasion and plastic deformation of the sharp cutting edge were the main wear mechanisms affecting tool performance, particularly at higher cutting conditions. The flake-like oxide debris were observed to increase when machining workpiece material with higher nickel and chromium content in their composition. Tool life was also found to have functional correlation between the cutting force, hardness and length of wear (AFM) along the nose region.