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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

77

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)

37

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

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

ASTM B673: Standard Specification for UNS N08904, UNS N08925, and UNS N08926 Welded Pipe

ASTM B674: Standard Specification for UNS N08904, UNS N08925, and UNS N08926 Welded Tube

ASTM B677: Standard Specification for UNS N08904, UNS N08925, and UNS N08926 Seamless Pipe and Tube

ASTM B649: Standard Specification for Ni-Fe-Cr-Mo-Cu Low-Carbon Alloy (UNS N08904), Ni-Fe-Cr-Mo-Cu-N Low-Carbon Alloys (UNS N08925, UNS N08031, and UNS N08926), and Cr-Ni-Fe-N Low-Carbon Alloy (UNS R20033) Bar and Wire

ASTM A182: Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service

ASTM A276: Standard Specification for Stainless Steel Bars and Shapes

Nickel Alloys, Ulrich Heubner (editor), 1998

ASTM A240: Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications

Welding Metallurgy of Stainless Steels, Erich Folkhard et al., 2012

ASTM A959: Standard Guide for Specifying Harmonized Standard Grade Compositions for Wrought Stainless Steels