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AISI 304 (S30400) Stainless Steel

AISI 304 stainless steel is an austenitic stainless steel formulated for primary forming into wrought products. 304 is the AISI designation for this material. S30400 is the UNS number. Additionally, the British Standard (BS) designation is 304S15. And the AFNOR (French) designation is Z7Cn18-09.

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

The properties of AISI 304 stainless steel include five common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare AISI 304 stainless steel to: wrought austenitic 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.

1/16-Hard 304 Stainless Steel 1/8-Hard 304 Stainless Steel

Annealed 304 Stainless Steel Half-Hard 304 Stainless Steel

Quarter-Hard 304 Stainless Steel

Mechanical Properties

Brinell Hardness

170 to 360

Elastic (Young's, Tensile) Modulus

200 GPa 29 x 10⁶ psi

Elongation at Break

8.0 to 43 %

Fatigue Strength

210 to 440 MPa 30 to 63 x 10³ psi

Poisson's Ratio

0.28

Shear Modulus

77 GPa 11 x 10⁶ psi

Shear Strength

400 to 690 MPa 58 to 100 x 10³ psi

Tensile Strength: Ultimate (UTS)

580 to 1180 MPa 84 to 170 x 10³ psi

Tensile Strength: Yield (Proof)

230 to 860 MPa 34 to 120 x 10³ psi

Thermal Properties

Latent Heat of Fusion

290 J/g

Maximum Temperature: Corrosion

420 °C 790 °F

Maximum Temperature: Mechanical

710 °C 1300 °F

Melting Completion (Liquidus)

1450 °C 2640 °F

Melting Onset (Solidus)

1400 °C 2550 °F

Specific Heat Capacity

480 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

16 W/m-K 9.2 BTU/h-ft-°F

Thermal Expansion

17 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

2.4 % IACS

Electrical Conductivity: Equal Weight (Specific)

2.7 % IACS

Otherwise Unclassified Properties

Base Metal Price

15 % relative

Calomel Potential

-80 mV

Density

7.8 g/cm³ 490 lb/ft³

Embodied Carbon

3.0 kg CO₂/kg material

Embodied Energy

43 MJ/kg 18 x 10³ BTU/lb

Embodied Water

150 L/kg 17 gal/lb

Common Calculations

PREN (Pitting Resistance)

Resilience: Ultimate (Unit Rupture Work)

86 to 250 MJ/m³

Resilience: Unit (Modulus of Resilience)

140 to 1870 kJ/m³

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

21 to 42 points

Strength to Weight: Bending

20 to 32 points

Thermal Diffusivity

4.2 mm²/s

Thermal Shock Resistance

12 to 25 points

Alloy Composition

Among wrought stainless steels, the composition of AISI 304 stainless steel is notable for containing comparatively high amounts of chromium (Cr) and nickel (Ni). Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance. Nickel is primarily used to achieve a specific microstructure. In addition, it has a beneficial effect on mechanical properties and certain types of corrosion.

Iron (Fe)Fe		66.5 to 74
Chromium (Cr)Cr		18 to 20
Nickel (Ni)Ni		8.0 to 10.5
Manganese (Mn)Mn		0 to 2.0
Silicon (Si)Si		0 to 0.75
Nitrogen (N)N		0 to 0.1
Carbon (C)C		0 to 0.080
Phosphorus (P)P		0 to 0.045
Sulfur (S)S		0 to 0.030