5.5mm Diameter 440 Stainless Steel Ball Bearings (Hardened) Grade 100

High Quality Precision AISI 420 Stainless Steel Ball Bearings: Hardened AISI 420 stainless steel is probably the most widely used due to its wide range of uses and relatively low cost compared to other types of stainless steel. They are hardened to 52-55 HRC on the Rockwell Scale, they offer high material strength and fair corrosion resistance from alcohol, ammonia, food environments, fresh water, mild acid environments and many petroleum products.