Abstract: In order to research the influence of effective grainsin the vitrified bond CBN grinding wheel surface on wheel grinding performances,which is in low concentration,effective grains percentage model was established firstly,and a new method of detection and statistics for effective grains was proposed.And then,a series of grinding experiments for six wheels in different concentrations and in different levels of granularity were carried out.The results demonstrated that decreasing concentration of wheels can increase the percentage of effective grains in static state,and improve grain utilization,nonetheless,the grinding performances deterioratein the condition of concentration below 30 %.At the same time,increasing concentration of wheels can increase the number of effective grains in static state,and enhance wheel grinding ability,never the less,the grinding performances cannot gain further advance and the wheel cost efficient will drop seriously in the condition of concentration above 70 %.Besides,in the comparison of low concentration grinding wheels in different levels of granularity,fine grain wheel can gain better performance under the same condition.

Key words: low concentration, vitrified bond CBN wheel, effective grains, grinding performance