Steel Grit is made by crushing steel shot to angular particle subsequently tempered to different hardness to cater for different application, screened by size according to SAE Standard specification.  
Chemical Composition
The finished grit shall have the chemical compositions as follows:
Carbon 0.85-1.20%
Silicon 0.45-1.50%
Manganese 0.35-1.20%
Phosphorus <0.05%
Sulfur <0.05%
  Standard Hardness
The steel grit is manufactured by crushing the fully hardened shot to granular grit form, screening and tempered to three different hardness range as follows :
GH = 63-67 HRc.
GL = 56-60 HRc.
GP = 40-50 HRc.
It is also available in tempering to various hardness range for special application
The microstructure of steel grit shall be uniform martensite, tempered to a degree consistent with the hardness range,with fine,well distributed carbides, if any.
The density of steel grit shall be not less than 7.4 g/cc.
Size Distribution (as per SAE J 827)