... CompositionsteelCertificationISO9001Polish ball/ Grinding ball/grinding media1) Chrome steel grinding balls; AISI52100 Chrome steel, through hardness 62-65 rockwell '' C'' ,super- ... hardened , AISI 1085 through hardened, AISI1065 Through hardened, Super-fine surface available, 0.5mm to 25.4mm3) Stainless ... grinding balls: AISI302, 304, 316,420,440 , Super-fine surface available 2mm to 25.4mm Polish ...