Improvement of cutting performance for carbide tools via chlorine ion implantation

Recent demand for reduction of environmental burdens requires minimum use of lubricant oils even in machining the automotive parts. In order to put this dry machining into practice, the tribological properties of cutting tools must be significantly improved. The self-lubrication has been proposed for TiN coating films on the high-speed tool steel via the chlorine ion implantation. Since the implanted chlorine works as a catalyst for surface reaction from TiN to TiOx (1≦x≦2) in the wear track, the wear volume, as well as the friction coefficient, is significantly reduced by successive formation of lubricious oxides, i.e. TiOx. In the present paper, a turning test is employed to investigate the effect of this chlorine implantation on the cutting performance of various carbide tools. The cutting performance is compared among three tools: carbide tools without coating, TiN- or TiCN-coated carbide tools and Cl-implanted carbide tools with or without TiCN coating. Direct measurement of cutting forces reveals that the friction coefficient and wear are significantly reduced when using the Cl-implanted tools. In addition, adhesive wear is suppressed by using this Cl-implanted cutting tool, so that high-speed machining could be conducted up to a cutting speed of 500 m/min.