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AISI 204 (S20400) Stainless Steel

AISI 204 stainless steel is an austenitic stainless steel formulated for primary forming into wrought products. 204 is the AISI designation for this material. S20400 is the UNS number.

It has the lowest base cost among wrought austenitic stainless steels. In addition, it has the lowest embodied energy and can have a moderately high tensile strength.

The properties of AISI 204 stainless steel include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare AISI 204 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.

Mechanical Properties

Brinell Hardness

210 to 330

Elastic (Young's, Tensile) Modulus

200 GPa 29 x 106 psi

Elongation at Break

23 to 39 %

Fatigue Strength

320 to 720 MPa 47 to 100 x 103 psi

Poisson's Ratio

0.28

Shear Modulus

77 GPa 11 x 106 psi

Shear Strength

500 to 700 MPa 73 to 100 x 103 psi

Tensile Strength: Ultimate (UTS)

730 to 1100 MPa 110 to 160 x 103 psi

Tensile Strength: Yield (Proof)

380 to 1080 MPa 55 to 160 x 103 psi

Thermal Properties

Latent Heat of Fusion

280 J/g

Maximum Temperature: Corrosion

410 °C 760 °F

Maximum Temperature: Mechanical

850 °C 1560 °F

Melting Completion (Liquidus)

1410 °C 2570 °F

Melting Onset (Solidus)

1370 °C 2490 °F

Specific Heat Capacity

480 J/kg-K 0.12 BTU/lb-°F

Thermal Conductivity

15 W/m-K 8.7 BTU/h-ft-°F

Thermal Expansion

17 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

2.4 % IACS

Electrical Conductivity: Equal Weight (Specific)

2.9 % IACS

Otherwise Unclassified Properties

Base Metal Price

10 % relative

Density

7.7 g/cm3 480 lb/ft3

Embodied Carbon

2.4 kg CO2/kg material

Embodied Energy

35 MJ/kg 15 x 103 BTU/lb

Embodied Water

130 L/kg 16 gal/lb

Common Calculations

PREN (Pitting Resistance)

20

Resilience: Ultimate (Unit Rupture Work)

240 to 250 MJ/m3

Resilience: Unit (Modulus of Resilience)

360 to 2940 kJ/m3

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

27 to 40 points

Strength to Weight: Bending

24 to 31 points

Thermal Diffusivity

4.1 mm2/s

Thermal Shock Resistance

16 to 24 points

Alloy Composition

Among wrought stainless steels, the composition of AISI 204 stainless steel is notable for containing a comparatively high amount of manganese (Mn). Manganese is used to improve ductility at elevated temperatures. It also permits a higher nitrogen content than would otherwise be possible.

Iron (Fe)Fe 69.6 to 76.4
Chromium (Cr)Cr 15 to 17
Manganese (Mn)Mn 7.0 to 9.0
Nickel (Ni)Ni 1.5 to 3.0
Silicon (Si)Si 0 to 1.0
Nitrogen (N)N 0.15 to 0.3
Phosphorus (P)P 0 to 0.040
Carbon (C)C 0 to 0.030
Sulfur (S)S 0 to 0.030

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

Followup Questions

Similar Alloys

Further Reading

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

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

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

Corrosion of Austenitic Stainless Steels: Mechanism, Mitigation and Monitoring, H. S. Khatak and B. Raj (editors), 2002

Austenitic Stainless Steels: Microstructure and Mechanical Properties, P. Marshall, 1984

Properties and Selection: Irons, Steels and High Performance Alloys, ASM Handbook vol. 1, ASM International, 1993

ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994

Advances in Stainless Steels, Baldev Raj et al. (editors), 2010