... .4mm, 1/4",3/16",5/32",1/8",7/32",5/16",7/8",1",etc3. Grade: G100-G30004. Hardness (HRC ... , hardware, grinding media,Valve, aerosol and finger pump, bearings, and electronic components6. Standard: GB/T-308-2002, GB/T1148-93Production process ... acidAISI 4200.07~ 0.251.00 Max1.00 Max12.0~ 14.00.045 Max0.03 MaxMagnetic,martensite steel. flat surface HRC ...