Online hardness convertor Hardness Conversion ASTM E140-97 from HV: Vickers Hardness HB: Brinell Hardness 10 mm C-ball 3000 kgf HK: Knoop Hardness 500 gf and over HRA: Rockwell A Hardness 60 kgf. HRB: Rockwell B Hardness 100 kgf. HRC: Rockwell C Hardness 150 kgf. HRD: Rockwell D Hardness 100 kgf. HR15N: Rockwell Superficial 15 kgf. HR30N: Rockwell Superficial 30 kgf. HR45N: Rockwell Superficial 45 kgf. HSc: Scleroscope Hardness to HV: Vickers Hardness HB: Brinell Hardness 10 mm C-Ball 3000 kgf HRC: Rockwell C Hardness 150 kgf.