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AISI 304 (1.4301, S30400) Stainless Steel

AISI 304 stainless steel is an austenitic stainless steel. 304 is the AISI designation for this material. 1.4301 is the EN numeric designation. S30400 is the UNS number. Additionally, the EN chemical designation is X5CrNi18-10. And the British Standard (BS) designation is 304S15.

It has five common variants, each represented as a separate material. The material properties section shows ranges encompassing all variants. To see the details of each variant on a separate page, follow the links in the Variant Materials section further below.

Mechanical Properties

Graph bars compare AISI 304 stainless steel to other materials. From top to bottom: austenitic stainless steel, iron alloys, and the entire database.

Elastic (Young's, Tensile) Modulus

220 GPa 32 x 106 psi

Elongation at Break

8.1 to 44 %

Modulus of Resilience (Unit Resilience)

130 to 1730 kJ/m3

Poisson's Ratio


Strength to Weight Ratio

76 to 150 kN-m/kg

Tensile Strength: Ultimate (UTS)

590 to 1200 MPa 86 to 170 x 103 psi

Tensile Strength: Yield (Proof)

240 to 870 MPa 34 to 130 x 103 psi

Unit Rupture Work (Ultimate Resilience)

89 to 260 MJ/m3

Thermal Properties

Melting Onset (Solidus)

1400 °C 2550 °F

Specific Heat Capacity

450 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

16 W/m-K 9.2 BTU/h-ft-°F

Thermal Diffusivity

4.5 m2/s

Thermal Expansion

13 µm/m-K

Other Material Properties

Base Metal Price

25 % relative

Calomel Potential

-80 mV


7.8 g/cm3 490 lb/ft3

Electrical Conductivity: Equal Volume

13 % IACS

Electrical Conductivity: Equal Weight (Specific)

15 % IACS

Electrical Resistivity Order of Magnitude

-6.5 10x Ω-m

Embodied Carbon

3.0 kg CO2/kg material

Embodied Energy

43 MJ/kg 18 x 103 BTU/lb

Embodied Water

140 L/kg 17 gal/lb

PREN (Pitting Resistance)


Alloy Composition

Iron (Fe) 66.5 to 74.5
Chromium (Cr) 17.5 to 20
Nickel (Ni) 8.0 to 10.5
Manganese (Mn) 0 to 2.0
Silicon (Si) 0 to 1.0
Nitrogen (N) 0 to 0.1
Carbon (C) 0 to 0.080
Phosphorus (P) 0 to 0.045
Sulfur (S) 0 to 0.030

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

Followup Questions

Variant Materials

Similar Alloys

Further Reading

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

ASTM A276: Standard Specification for Stainless Steel Bars and Shapes

ASTM A473: Standard Specification for Stainless Steel Forgings

ASTM A479: Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels

ASTM A666: Standard Specification for Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate, and Flat Bar

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

EN 10088-1: Stainless steels - Part 1: List of stainless steels

EN 10088-2: Stainless steels - Technical delivery conditions for sheet/plate and strip of corrosion resisting steels for general purposes