針状砥粒のホーニング加工による切削性能の検討とその利用

Abstract

A splintery grain which is obtained at the early stage of milling process has comparatively slender appearance and sharp cutting edges, but is considerably friable due to existing crystal defects. With the view of positive utilization of this grain's feature, this paper reports on its cutting performance and the effectiveness when applied to the materials of poor grindability producing severe loading. One of the characteristics of honing work is that it exhibits remarkable differences in behaviors of cutting and stick wear at stick pressures before and after the critical pressure Pc, which is mainly attributed to the relation in magnitude between exerting cutting force on the acting grain and its strength. Comparison was made between two vitrified sticks of WA 150 having the same hardness which are made of the splintery grain S and the blocky or mulled grain R of special make, respectively. Generally, in the finishing of steels, for example, the stick S has pretty low Pc and excessive stick wear at Pc and therefore is of no benefit. But, a little crosshatch angle can suppress grain fragmentation, and consequently makes stick wear close to the level of the stick R. In the finishing of aluminum the stick S is superior at stock removal, stick wear and surface roughness. Also in that of austenitic stainless steel, the treated stick S (S) covered the friable grain by plugging the pore with sulfur somewhat surpasses the treated stick R(S).