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.
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.