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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.

This material is available from:

Diversified Metals, Inc.

Where Quality Isn't Expensive....It's Priceless
Located Monson and Palmer, MA
Products Specialty and hard to find metals, specializing in naval defense alloys
Services Heat treatment, upgrade testing, UT/LP, and product size conversion
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Link Visit their website to enquire about AISI 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)

20

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 m2/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) 66.5 to 74
Chromium (Cr) 18 to 20
Nickel (Ni) 8.0 to 10.5
Manganese (Mn) 0 to 2.0
Silicon (Si) 0 to 0.75
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

Similar Alloys

Further Reading

ASTM A493: Standard Specification for Stainless Steel Wire and Wire Rods for Cold Heading and Cold Forging

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 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

Creep-Resistant Steels, Fujio Abe et al. (editors), 2008

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

Advanced Materials in Automotive Engineering, Jason Rowe (editor), 2012

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