Stainless steel film of chromium oxide by reaction with the oxygen in air and even the small amount of dissolved oxygen in water. This passive film prevents further corrosion by blocking oxygen diffusion to the steel surface and thus prevents corrosion from spreading into the bulk of the metal. This film is self-repairing if it is scratched or temporarily disturbed by an upset condition in the environment that exceeds the inherent corrosion resistance of that grade. However, stainless steels may suffer uniform corrosion when exposed to acidic or basic solutions. Whether a stainless steel corrodes depends on the kind and concentration of
SAE 904L stainless steel SAE 904L stainless steel 904L is an austenitic stainless steel. In comparison to 316L, its molybdenum addition gives it superior resistance to localized attack (pitting and crevice corrosion) by chlorides and greater resistance reducing acids and in particular its copper addition gives it useful corrosion resistance to all concentrations of sulphuric acid. Its high alloying content also gives it greater resistance to chloride stress corrosion cracking, but it is still susceptible. Its low carbon content makes it resistant to sensitization by welding and which prevents intergranular corrosion. It has applications in piping systems, pollution control equipment, heat exchangers, and bleaching