4mm Diameter Grade 100 Hardened AISI 440 Stainless Steel Ball Bearing

General Purpose Grade 100 440 Stainless Ball Bearings: High Quality Graded 440 Stainless Steel Ball bearings made from AISI 440 Stainless Steel with a hardness of 57 - 60 HRC Rockwell Scale, the hardness is all the way through the ball. These are the same stainless 440 steel balls used to manufacture bearing assemblies and have a high duty and life cycle.
Martensitic Stainless steel offering high hardness and tensile strength against fresh water, steam, petroleum spirits and alcohols.
Manufactured in compliance to the following international standards: AISI 440 / Wks 1.4125 / DIN X105CrMo17 / AFNOR Z100CD17 / JIS SUS 440