AISI 308 (S30800) Stainless Steel
AISI 308 stainless steel is an austenitic stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. 308 is the AISI designation for this material. S30800 is the UNS number.
The graph bars on the material properties cards below compare AISI 308 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
160
Elastic (Young's, Tensile) Modulus
200 GPa 29 x 106 psi
Elongation at Break
45 %
Fatigue Strength
210 MPa 31 x 103 psi
Poisson's Ratio
0.28
Reduction in Area
57 %
Rockwell B Hardness
76
Shear Modulus
78 GPa 11 x 106 psi
Shear Strength
410 MPa 60 x 103 psi
Tensile Strength: Ultimate (UTS)
590 MPa 85 x 103 psi
Tensile Strength: Yield (Proof)
230 MPa 34 x 103 psi
Thermal Properties
Latent Heat of Fusion
290 J/g
Maximum Temperature: Corrosion
420 °C 790 °F
Maximum Temperature: Mechanical
990 °C 1820 °F
Melting Completion (Liquidus)
1420 °C 2590 °F
Melting Onset (Solidus)
1380 °C 2510 °F
Specific Heat Capacity
480 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
15 W/m-K 8.8 BTU/h-ft-°F
Thermal Expansion
16 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.4 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.8 % IACS
Otherwise Unclassified Properties
Base Metal Price
17 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
3.2 kg CO2/kg material
Embodied Energy
46 MJ/kg 20 x 103 BTU/lb
Embodied Water
150 L/kg 18 gal/lb
Common Calculations
PREN (Pitting Resistance)
20
Resilience: Ultimate (Unit Rupture Work)
210 MJ/m3
Resilience: Unit (Modulus of Resilience)
140 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
21 points
Strength to Weight: Bending
20 points
Thermal Diffusivity
4.1 mm2/s
Thermal Shock Resistance
13 points
Alloy Composition
Among wrought stainless steels, the composition of AISI 308 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.
| Fe | 64.1 to 71 | |
| Cr | 19 to 21 | |
| Ni | 10 to 12 | |
| Mn | 0 to 2.0 | |
| Si | 0 to 0.75 | |
| C | 0 to 0.080 | |
| P | 0 to 0.045 | |
| S | 0 to 0.030 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM A167: Standard Specification for Stainless and Heat-Resisting Chromium-Nickel Steel Plate, Sheet, and Strip
ASTM A473: Standard Specification for Stainless Steel Forgings
Welding Metallurgy of Stainless Steels, Erich Folkhard et al., 2012
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