SPECS Steel Shot Steel Grit GP Steel Grit GB Steel Grit GL Steel Grit GH Shape when new round angular angular angular angular Shape in the operating mix round round angular angular angular Sieve analysis According to standard SAE J 444 Chemical analysis carbon >= 0.85% ; phosphorus =< 0.05% ; sulfur =< 0.05% Average analysis - Tukon tester - Knoop diamond point - 1000 g load Normal 40 - 50 Rc ----------------- Other hardness available 40-50 Rc 50-56 Rc 56-60 Rc 60-66 Rc - Vickers durometer - 1000g load 390-510 HV ------------------ Other hardness available 390-510 HV 510-610 HV 610-690 HV >= 700 HV   On 10 measurements taken halfway across the particle radius.   Arithmetic mean of absolute values of deviations : =< 3 Rc Standard deviation +/- 3 Rc or +/- 40 HV +/- 3 Rc or +/- 40 HV +/- 3 Rc or +/- 50 HV +/- 3 Rc or +/- 60 HV +/- 3 Rc or +/- 80 HV Microstructure   Minimum density measured by alcohol displacement >= 7.3 g/cu.cm.   >= 7.6 g/cu.cm.