Ceramic Vitrified Bond Of Super-hard Material CBN For Grinding Wheel With Low Melting Point

With the development of scientific technology, new materials are emerging. This phenomenon makes that the areas of machining are growing and processing quality requirements are also raising. Machining of new technology for high-quality, high precision and high efficiency, low cost, CBN grinding wheel of the ceramics vitrified bond with the application of the increasingly wide usage continue to grow. CBN grinding wheel of ceramic vitrified bond is considered as a tool of high-speed, high-efficiency, high-precision, low-cost grinding, low pollution, high-performance abrasive.The traditional type of CBN grinding wheel with ceramic vitrified bond was sintered at a high temperature (above 1200℃). This made the CBN grind granules damaged and also changed blunt CBN grind granules into pliable ones. All these damages seriously decreased the grinding property.Low melting point and high strength vitrified bond is prepared to realize sintering of vitrified bond super hard grinding tools at lower temperature. Raw materials were mainly clay, boric glass, metal-oxide and some alkali metal oxides. In this work,10 kinds of melting glass materials were tried to decide which is better for make vitrified bond, when the sintering temperature is 650℃(or 700℃). The observation and analysis of the glass materials can be made out by the luidity and morphology of glass materials after they were cooled. The best three melting glasses were choosen to make vitrified bonds. The results show that if the content of the SiO2 and Al2O3 increased, the melting glass will have a higher melting temperature; if the content of the alkali metal oxide (R2O) and B2O3 increased, the glass melting temperature will be significantly decreased. The glass melting temperature for vitrified bond No.1 is 1200℃, and the glass melting temperature for vitrified bond No.2 and No.3 is 1100℃.The bending strength of 93 MPa was obtained for the samples of addition of 15wt% vitrified bond No.1 sintered at 700℃. The bending strength of 66 MPa was abstained for the samples of addition of 15wt% vitrified bond No.2 sintered at 650℃. The bending strength of 81 MPa was obtained for addition of 10wt% vitrified bond No.3 sintered at 650℃.The results of CBN grinding wheel materials show that the bending strength was 64 MPa for the addition of 15wt% vitrified bond No.1 sintered at 700℃. The bending strength of 66 MPa was abstained for the samples of addition of 10wt% vitrified bond No.3 sintered at 650℃. The vitrified bond No.1 and vitrified bond No.3 has high bending strength and low melting point, so that can be used for making CBN grinding wheel.