Rationale

Required (Specified) Hardness grades defined in 15-point HRB ranges are currently produced in the industry, however these grades are not defined by any ASTM specification for zinc metallic coated steel sheet. These grades are published for non-metallic coated steel sheet in ASTM A1008. This ballot item is introducing these required hardness grades to ASTM A653, in harmony with ASTM A1008.