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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.

Iron (Fe)Fe 46.7 to 56.5
Chromium (Cr)Cr 23 to 26
Nickel (Ni)Ni 19 to 22
Silicon (Si)Si 1.5 to 3.0
Manganese (Mn)Mn 0 to 2.0
Carbon (C)C 0 to 0.25
Phosphorus (P)P 0 to 0.045
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

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