Stainless Steel Balls: AISI-440C
View Sizes, Grades, and Tolerance. Profile. AISI 440C stainless steel balls provide maximum hardness, toughness and dimensional stability. They are highly resistant to rolling-contact fatigue. 440C stainless steel balls are used in a hardened condition, perform similarly to tool steels, and are ideal for antifriction bearings (rolling bearings).