Influence of vitrified bond structure on radial wear of cBN grinding wheels

This paper presents the results of research concerning the radial wear of super hard grinding wheels in the process of internal grinding of bearing rings. The new-developed grinding wheel is designed for bonding the abrasive grains of submicrocrystalline boron nitride using a glass–ceramic bond. This grinding wheel is compared to cBN grinding wheels composed from ceramic bonding systems, currently having application in industry. A crystalline phase from a group of single-diagonal pyroxenes of an XYSi2O6 type was generated at the glass–ceramic bond from a CaO–MgO–Al2O3–B2O3–SiO2 system. An influence of the presence of this phase on the bond fracture toughness coefficient KIc and the elastic modulus E of cBN grinding wheels was examined. Compared to grinding wheels comprising the commercial bond from a Na2O–K2O–Al2O3–B2O3–SiO2 system, the microcrystalline structure of the new-developed bond limits the range of its fragmentation in the process of grinding. It exerts a marked influence on the formation of different roughness profiles on the wheel working surface and the wear resistance, compared to a grinding wheel composed from a commercial bond.