AISI 314 (S31400) Stainless Steel
AISI 314 stainless steel is an austenitic stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. 314 is the AISI designation for this material. S31400 is the UNS number.
It has a moderately low electrical conductivity among wrought austenitic stainless steels. In addition, it has a moderately high base cost and a moderately high embodied energy.
The graph bars on the material properties cards below compare AISI 314 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
180
Elastic (Young's, Tensile) Modulus
200 GPa 29 x 106 psi
Elongation at Break
45 %
Fatigue Strength
210 MPa 30 x 103 psi
Poisson's Ratio
0.28
Reduction in Area
57 %
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 33 x 103 psi
Thermal Properties
Latent Heat of Fusion
330 J/g
Maximum Temperature: Corrosion
440 °C 830 °F
Maximum Temperature: Mechanical
1100 °C 2010 °F
Melting Completion (Liquidus)
1380 °C 2520 °F
Melting Onset (Solidus)
1340 °C 2440 °F
Specific Heat Capacity
490 J/kg-K 0.12 BTU/lb-°F
Thermal Conductivity
15 W/m-K 8.5 BTU/h-ft-°F
Thermal Expansion
15 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.0 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.3 % IACS
Otherwise Unclassified Properties
Base Metal Price
25 % relative
Density
7.7 g/cm3 480 lb/ft3
Embodied Carbon
4.3 kg CO2/kg material
Embodied Energy
62 MJ/kg 27 x 103 BTU/lb
Embodied Water
190 L/kg 23 gal/lb
Common Calculations
PREN (Pitting Resistance)
25
Resilience: Ultimate (Unit Rupture Work)
210 MJ/m3
Resilience: Unit (Modulus of Resilience)
130 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
3.9 mm2/s
Thermal Shock Resistance
14 points
Alloy Composition
Among wrought stainless steels, the composition of AISI 314 stainless steel is notable for containing comparatively high amounts of silicon (Si) and chromium (Cr). Silicon content is typically governed by metallurgical processing concerns, but it can also be added for the purpose of improving oxidation resistance. Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance.
| Fe | 46.7 to 56.5 | |
| Cr | 23 to 26 | |
| Ni | 19 to 22 | |
| Si | 1.5 to 3.0 | |
| Mn | 0 to 2.0 | |
| C | 0 to 0.25 | |
| 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
EN 10095: Heat resisting steels and nickel alloys
ASTM A473: Standard Specification for Stainless Steel Forgings
Welding Metallurgy and Weldability of Stainless Steels, John C. Lippold and Damian J. Kotecki, 2005
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