904L is an austenitic stainless steel. It is softer than 316L, and its molybdenum addition gives it superior resistance to localized attack by chlorides and greater resistance reducing acids; in particular, its copper addition gives it useful corrosion resistance to all concentrations of sulfuric 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 prevents intergranular corrosion.