|440 Stainless Steel balls are a martenistic-type stainless steel which is used extensively in steel ball bearing applications that require hardness, dimensional stability, corrosion resistance and toughness. 440 Stainless Steel is also used for corrosion-resistant ball and check valves. 440 ball are resistant to corrosion from fresh water, steam, crude oil, gasoline, perspiration, alcohol, blood and food stuffs. Maximum resistance to corrosion and tarnishing is only achieved when 440 is fully hardened and surfaces are polished to a high luster. 440 is also magnetic.