Stainless Steel Grade 904L - Super Austenitic Anti-Corrosion

 

 

Nominal Chemical Composition of 904L (UNS N08904) Stainless Steel

Element	Symbol	Typical Content (wt. %)	Function / Role
Iron	Fe	Balance (~50.0–55.0%)	Base matrix of the alloy; supports all alloying elements
Chromium	Cr	19.0–23.0	Promotes passivation; improves resistance to general and localized corrosion
Nickel	Ni	23.0–28.0	Stabilizes austenitic phase; increases ductility and chloride SCC resistance
Molybdenum	Mo	4.0–5.0	Enhances pitting and crevice corrosion resistance (PREN boost)
Copper	Cu	1.0–2.0	Increases resistance to non-oxidizing acids (e.g., H₂SO₄, H₃PO₄)
Carbon	C	≤ 0.02	Minimizes carbide precipitation; prevents sensitization
Manganese	Mn	≤ 2.0	Deoxidizer; assists in sulfur resistance and hot workability
Silicon	Si	≤ 1.0	Enhances oxidation resistance; used as a deoxidizer in steelmaking
Phosphorus	P	≤ 0.045	Residual element; kept low to avoid embrittlement
Sulfur	S	≤ 0.035	Residual element; minimized to maintain ductility and corrosion performance
Nitrogen	N	≤ 0.10	Strengthens the austenitic matrix; improves pitting resistance