This standard specifies diamond or CBN and (abrasive) grains used in the manufacture of diamond or CBN tools such as wheels and segment saws. It is called a [abrasive] grain. ] The types and expression methods of particle size and the method of particle size testing are specified.
JIS B 4130:1998 history
1998JIS B 4130:1998 Diamond/CBN products -- Grain sizes of diamond or cubic boron nitride
1982JIS B 4130:1982 Grain sizes of diamond or cubic boron nitride