SS904L AISI 904L Stainless Steel (UNS N08904) Material Properties, Composition, Hardness

ASTM SAE AISI 904L Stainless Steel (UNS N08904)

AISI 904L stainless steel (UNS N08904) is a high alloy austenitic stainless steel. Compared with 316L, SS904L has lower carbon (C) content, higher chromium (Cr) content, and approximatively twice the nickel (Ni) and molybdenum (Mo) content of 316L, which makes it have higher high temperature oxidation resistance, pitting resistance, and resistance to reducing acid (eg, sulfuric acid). Nitrogen (N) can reduce the rate of chromium carbide precipitation, thereby reducing the sensitivity of sensitization, it also improve the resistance to pitting and crevice corrosion caused by chlorides. Especially its addition of copper (Cu) makes it useful for all concentrations of sulfuric acid.

Datasheet and Specification

The following data sheet summarizes the chemical composition, properties, heat treatment and equivalent grade of 904L stainless steel (SS904L).

Chemical Composition

The following data sheet gives SS 904L stainless steel chemical composition.

Chemical Composition, %
ASTM UNS Type C, ≤ Si, ≤ Mn, ≤ P, ≤ S, ≤ Cr Ni Mo N, ≤ Cu Notes (Product)
ASTM A276/A276M UNS S08904 904L 0.02 1.00 2.00 0.045 0.030 19.0-23.0 23.0-28.0 4.0-5.0 0.10 1.0-2.0 Bars and Shapes
ASTM A240/A240M Plate, Sheet, and Strip

Mechanical Properties

The following table lists Rolex 904L stainless steel (SS904L) mechanical properties such as yield strength, tensile strength, elongation and hardness.

AISI ASTM 904L Steel Mechanical Properties
ASTM AISI Type Tensile Strength, MPa (ksi), ≥ 0.2% Yield Strength, MPa (ksi), ≥ Elongation in 50 mm (2 in.), %, ≥ Rockwell Hardness (HRBW), ≤ Product forms Conditions
ASTM A276/A276M 904L (UNS N08904) 490 (71) 220 (31) 35 Bars and Shapes Annealed, Hot-finished or cold-finished
ASTM A240/A240M 490 (71) 220 (31) 35 90 Plate, Sheet, and Strip

Heat Treatment

Annealing: The recommended annealing temperatures for 904L wrought steel is 1095 °C (2000 °F).


Type 304 stainless steel can handle mild foods and vegetables, but sauces and pickle liquors are more corrosive and can even cause pitting corrosion on type 316 stainless steel. In order to improve pitting resistance, high alloy 904L stainless steel (SS904L) should be considered.


904L stainless steel (SS904L) is used in petroleum, chemical, fertilizer, marine development towers, tanks, pipes and tubes and heat exchangers. Rolex and other watch manufacturers also use it to make watches.

SS 904L Equivalent Grade

The datasheet below summarizes Rolex 904L stainless steel equivalent grade such as European EN (German DIN EN, British BS EN, French NF EN…), Chinese GB, ISO, Japanese JIS standard.

AISI 904L equivalent material
US European Union ISO Japan China Australia India Rusia Korea
Standard Type Standard Grade (Steel Number) Standard ISO Name (ISO Number) Standard Grade Standard Grade Standard Grade Standard Grade Standard Grade Standard Grade
AISI SAE; ASTM 904L (UNS N08904) EN 10088-2; EN 10088-3 X1NiCrMoCu25-20-5 (1.4539) ISO 15510 X1NiCrMoCu25-20-5 (4539-089-04-I) JIS G4303 SUS 890L GB/T 20878; GB/T 4237; GB/T 3280 015Cr21Ni26Mo5Cu2

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