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.
| Fe | 69.6 to 76.4 | |
| Cr | 15 to 17 | |
| Mn | 7.0 to 9.0 | |
| Ni | 1.5 to 3.0 | |
| Si | 0 to 1.0 | |
| N | 0.15 to 0.3 | |
| P | 0 to 0.040 | |
| C | 0 to 0.030 | |
| 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