Investigation of use of cubic boron nitride (cBN) as alternative abrasive in natural stone cutting tools

Investigation of Use of Cubic Boron Nitride (cBN) as Alternative Abrasive in Natural Stone Cutting Tools In this study, all the sockets containing of metal and/or diamond, in which designed for natural stone cutting were produced in hot-press by powder metallurgy method. 85-15 CuSn bronze powder was choosen as a matrix material into which 30/40 and 40/50 US mesh grain size of diamond and/or cBN grains was added with a concentration of 30 %. The production of sockets used in this investigation was carried out under 35 MPa pressure at 600, 650, 700 °C sintering temperature for 3 minutes. The cutting performance of each socket welded around a circular cutting disc with a diameter 300 mm was measured. In this natural stone cutting process, Ankara-Andezit stone with a dimension of 30x150x1500 mm was used. The wear values of the sockets after the cutting process were measured with a digital calliper with a precision of 0.01 mm. Each socket was inspected for its chemical composition and microstructure properties by using a scanning electron microscope (SEM), X-ray diffraction spectrometer (XRD) and Energy-dispersive X-ray spectroscopy (EDS). The results of the experimental studies show that the bending strength of diamond cutting tools is less than cBN cutting tools about 30% and cutting performance of diamond cutting tools were found two and a half times higher than cBN cutting tools. The SEM photographs show that the micro-plowing and matris tail are formed on wear surface. Besides, it is obtained that the cBN grains were worn more than diamond grains. Keywords: Diamond segment, hot press, powder metallurgy, sintering