MT-CVD法を用いて製作したTi(C,N)コーテッド工具の長寿命化に関する一考察

概要

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A Ti(C,N) coated tool which has a balanced performance of the expected high wear resistance in the coated layer with high toughness of the substrate, has been widely used for machining of ferrous materials. Applying this tool to the machining of the nodular cast iron, however, formation of the adhered layer at the tool tip occurred intensively, tool-tip failure and or separation of the coated layer tends to take place especially in semi-final and/or rough finishing. It is also indicated that there is possibility to yield a finished product with some faults caused by continued cutting operation without noticing serious damage occurred on the tool-tip. In the present investigation, effects of reducing the pre-existing cracks in tool surface layer, thickness of the coated layer and the existence of the ηphase in substrate material (WC-Co) on the tool life were extensively investigated in order to increase efficiency and to stabilize the tool life on the cutting process for semi-final finishing of rodular cast iron. As the results, it is clarified that the thinner the coated layer the lower became the tensile residual stress on the surface, resulting in the extension of the tool life without taking place separation of the coated layer. The separation is also able to suppress by controlling the surface roughness of the tool substrate to several μm with certain homogeneity.
公益社団法人精密工学会の論文
2003-06-05