砥石結合剤の組成が研削性能に及ぼす影響 (第2報)

Abstract

In the previous report, it was experimentally confirmed that mechanical properties of grinding wheels in equal grade were different when vitrified bonding material composition which consist of feldspar, pottery and clay minerals component varied. In this paper, the dry surface grinding experiments were performed on the grinding wheels which had different vitrified bonding material compositions and grinding forces and wear flat areas on the working surface of grinding wheels were measured, and then effects of the composition were studied. The results obtained are as follows. (1) The bending strength of grinding wheels are smaller than about 20 MPa or greater than about 30 MPa, most grinding wheels belong to shedding type or glazing, type respectively, and the grinding wheels belonged to both types are not related to the compositions and grades. (2) But if the bending strength is from about 20 to 30 MPa, the grinding wheel life depends remarkably on the composition in which contains feldspar component especially and percentage bond-ing material. (3) The bonding material containing a less feldspar component has low strength and poor adhesive ability. Therefore the grinding wheel using this bonding material must use more percentage bonding material than one containing more feldspar component for having a certain bending strength. Much percentage bonding material contributes to the increase of wear flat area on the grinding wheel and then the decrease of the grinding wheel life.