The Preparation and Key Technology of the PCBN Cutting Tool Materials Used in the Fine Finishing of Cast Iron Parts

The formula, the preparation process and the key technologies of the new polycrystalline cubic boron nitride (PCBN) cutting tool materials for Cast Iron Parts in High Speed Finish Machining are introduced in this article. In order to solve the problem of agglomeration of the fine particle powder, the parameters of the wet ball milling as well as the dispersion medium and dispersant are determined by the experimental study. Secondly, by using the advanced detection methods including the X-Ray Diffraction (XRD) analysis and the micro hardness testing, the best parameters of preparation of PCBN materials are developed, which provides a reliable guarantee for the batch quality stability of the tool materials. Finally, the effect of nano whisker on the properties of cutting tools used in the severe intermittent cutting is studied experimentally and the results show that the nano whisker can improve the impact toughness of the tool materials, but its additive amount has the best range. The microstructure and properties of the PCBN cutting tools are analyzed by means of the scanning electron microscopy (SEM), the energy spectrum analysis (EDS) and the micro hardness testing, which indicates that the microstructure of the PCBN tool materials is uniform and compact and the materials of PCBN tool have stable performance. The machining experimental results verify the effectiveness of the adopted key technologies and the prepared PCBN tool materials can meet the requirements of the surface roughness of the iron casting parts for the high-speed finish machining.