904L (UNS N08904 / 1.4539) is a high-performance super austenitic stainless steel with exceptional corrosion resistance properties. This premium grade features high levels of chromium (20%), nickel (25%), molybdenum (4.3%), and copper (1.5%) to provide outstanding resistance to a wide range of corrosive environments, particularly in sulfuric and phosphoric acids.

As a multipurpose austenitic stainless steel with a Pitting Resistance Equivalent Number (PREN) of ≥34, 904L offers superior corrosion resistance compared to standard austenitic grades like 316L. The combined addition of high nickel and molybdenum content provides enhanced resistance to stress corrosion cracking, while its low carbon content (≤0.020%) ensures excellent intergranular corrosion resistance in the welded condition.

904L stainless steel is particularly valued in applications dealing with medium to severe corrosive solutions, where its balanced combination of mechanical properties and corrosion resistance makes it an ideal choice for demanding industrial environments. This versatile grade provides approximately twice the strength of conventional 300-series stainless steels while maintaining excellent ductility and impact strength.