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UNS N08904 (904L) Stainless Steel

N08904 stainless steel is a superaustenitic (highly alloyed) stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. N08904 is the UNS number for this material. Additionally, the British Standard (BS) designation is 904S13. And the common industry name is Alloy 904L.

This material is well established: the Further Reading section below cites a number of published standards, and that list is not necessarily exhaustive.

It has a fairly low tensile strength among the wrought superaustenitic stainless steels in the database.

The graph bars on the material properties cards below compare N08904 stainless steel to: wrought superaustenitic stainless steels (top), all iron alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Brinell Hardness

170

Elastic (Young's, Tensile) Modulus

200 GPa 29 x 10⁶ psi

Elongation at Break

38 %

Fatigue Strength

200 MPa 30 x 10³ psi

Poisson's Ratio

0.28

Rockwell B Hardness

Shear Modulus

79 GPa 11 x 10⁶ psi

Shear Strength

370 MPa 53 x 10³ psi

Tensile Strength: Ultimate (UTS)

540 MPa 78 x 10³ psi

Tensile Strength: Yield (Proof)

240 MPa 35 x 10³ psi

Thermal Properties

Latent Heat of Fusion

300 J/g

Maximum Temperature: Corrosion

430 °C 800 °F

Maximum Temperature: Mechanical

1100 °C 2010 °F

Melting Completion (Liquidus)

1440 °C 2620 °F

Melting Onset (Solidus)

1390 °C 2530 °F

Specific Heat Capacity

470 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

12 W/m-K 6.8 BTU/h-ft-°F

Thermal Expansion

16 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

1.7 % IACS

Electrical Conductivity: Equal Weight (Specific)

1.9 % IACS

Otherwise Unclassified Properties

Base Metal Price

32 % relative

Density

8.1 g/cm³ 500 lb/ft³

Embodied Carbon

5.8 kg CO₂/kg material

Embodied Energy

79 MJ/kg 34 x 10³ BTU/lb

Embodied Water

200 L/kg 24 gal/lb

Common Calculations

PREN (Pitting Resistance)

Resilience: Ultimate (Unit Rupture Work)

170 MJ/m³

Resilience: Unit (Modulus of Resilience)

150 kJ/m³

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

19 points

Strength to Weight: Bending

18 points

Thermal Diffusivity

3.1 mm²/s

Thermal Shock Resistance

12 points

Alloy Composition

Among wrought stainless steels, the composition of N08904 stainless steel is notable for containing a comparatively high amount of nickel (Ni) and including copper (Cu). Nickel is primarily used to achieve a specific microstructure. In addition, it has a beneficial effect on mechanical properties and certain types of corrosion. Copper is used to improve resistance to acids, and to improve formability.

Iron (Fe)Fe		38.8 to 53
Nickel (Ni)Ni		23 to 28
Chromium (Cr)Cr		19 to 23
Molybdenum (Mo)Mo		4.0 to 5.0
Copper (Cu)Cu		1.0 to 2.0
Manganese (Mn)Mn		0 to 2.0
Silicon (Si)Si		0 to 1.0
Nitrogen (N)N		0 to 0.1
Phosphorus (P)P		0 to 0.045
Sulfur (S)S		0 to 0.035
Carbon (C)C		0 to 0.020