Alloy 20 is an
austenitic stainless steel containing less than 50% iron developed for applications involving
sulfuric acid. Its corrosion resistance also finds other uses in the
chemical,
petrochemical,
power generation, and
plastics industries. Alloy 20 resists
pitting and
chlorideion corrosion, better than
304 stainless steel and on par with
316L stainless steel. Its copper content protects it from sulfuric acid. Alloy 20 is often chosen to solve
stress corrosion cracking problems, which may occur with 316L stainless. Alloy of the same name with the designation "Cb-3" indicates
niobium (also known as columbium) stabilized.[1][2][3]