904L (UNS N08904) is a superaustenitic stainless steel that is designed for moderate to high corrosion
resistance in a wide range of process environments. The combination of high chromium and nickel content,
coupled with additions of molybdenum and copper, assure good to excellent corrosion resistance.
With its highly alloyed chemistry-25% nickel and 4.5% molybdenum, 904L provides good chloride stress
corrosion cracking resistance, pitting and general corrosion resistance superior to 316L and 317L
molybdenum enhanced stainless steels.

Alloy 904L was originally developed to withstand environments containing dilute sulfuric acid. It also offers
good resistance to other inorganic acids such as hot phosphoric acid as well as most organic acids.

Alloy 904L is easily welded and processed by standard shop fabrication practices.

The high content of alloying elements in 904L gives the alloy exceptionally good resistance to uniform corrosion.

904L was originally developed to withstand environments containing dilute sulfuric acid, and is one of the few
stainless steels that, at temperatures up to 95°F (35°C), provides full resistance in such environments within
the entire concentration range of 0 to 100%. 904L also offers good resistance to a number of other inorganic
acids, such as phosphoric acid and most organic acids. However, acids and acid solutions containing halide
ions can be very aggressive, and the corrosion resistance of 317L, 317LMN and 904L may be insufficient.
Fractional distillation of tall oil often needs better material than 316L or even the more frequently used 317LMN.
In these hot concentrated caustic solutions, the corrosion resistance is mainly determined by the nickel content
of the material. With a nickel content of 25%, 904L has proven to be a good alternative to most conventional
stainless steels.Conventional stainless steels such as 304L and 316L are susceptible to chloride stress corrosion
cracking (SSC) under certain conditions. Resistance to SSC increases with the increased content of nickel and
molybdenum. Therefore, the higher performance austenitic stainless steels such as 904L have very good
resistance to SSC. The table in the upper right corner shows resistance to SSC in a chloride solution under
evaporative conditions. High performance austenitic steels and duplex stainless steels clearly outperform 316L.

Other Grades:
201,202,21-4N,301,302,301L,303,303Se,304,304L,304H,304LN,304N,305,S38400,308,309,309S,310,310s,
316,316L,316H,316Ti,316N,316LN,317,317L,317LMN,317LN,321,321H,347,347H,S3100,S31803,S3205,
S32304,S31200,S31260,S32507,405,409,429,430,430F,434,444,403,410S,410,416,420,420F,431F,440A
440B,440C,440F,610,630,631,632,635,660,Alloy 200,Monel 400 ,Alloy K-500 ,Inconel 600 , Incconel 601,
Inconel 625 , Inconel 718 , Alloy 800 ,Alloy 800H,Alloy 800HT,Inconel 825,Alloy 276, Alloy 20, Alloy 59

Stainless Steel Plate/Coil/Flat Bar Process