904L is a high-alloy austenitic stainless steel with low carbon content. The grade is use under severe corrosive conditions. It has been application proved over many years now and was originally developed to resist corrosion in dilute sulfuric acid. Structurally, 904L is fully austenitic and is less sensitive to precipitation ferrite and sigma phases than conventional austenitic grades with high molybdenum content. Characteristically, due to the combination of relatively high contents of chromium, nickel, molybdenum and copper 904L has good resistance to general corrosion.
Hot work should proceed after uniform heating to 2000-2200 F. Does not work the material at less than 1800 F. Full annealing should follow any hot work to re attain maximum ductility and corrosion resistance.
Although higher forces are required, 904L will respond in a similar fashion to other austenitic stainless steels like 304, 316 or 317. Most common operations can be successfully performed.
C Cr Cu Mn Mo Ni P S Si Max Max Max Max Max 0.02 19.0-23.0 1.0-2.0 2.0 4.0-5.0 23.0-28.0 0.045 0.035 1.0
Grade Tensile Strength (MPa) Yield Strength 0.2% Elongation (% in 50mm) Hardness min Proof (MPa) min min Rockwell B (HR B) Brinell (HB) 904L 490 220 36 70-90 typical 150