Effect of the Coating System on the Tool Performance When Turning Heat Treated Aisi 4140

The effect of coating systems on the tool performance when turning heat treated AISI 4140 is outlined in this paper. Therefore, four differently coated cemented carbide indexable inserts (TiN, TiN+TiAlN+TiN, TiN+TiCN+Al2O3, TiN+TiCN+Al2O3+TiN) and tools of uncoated cemented carbide, serving as a reference for the capability of the coating systems, are used. The tool performance is evaluated by the path length due to primary motion and the results of the turning operation, such as the process forces and the temperatures of the cutting tool. Remarkable differences in terms of the tool life travel path were observed.