AISI 312 (S31200) Stainless Steel
AISI 312 stainless steel is a duplex stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. 312 is the AISI designation for this material. S31200 is the UNS number.
It has a moderately high thermal conductivity and a moderately low electrical conductivity among wrought duplex stainless steels.
The graph bars on the material properties cards below compare AISI 312 stainless steel to: wrought duplex 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
250
Elastic (Young's, Tensile) Modulus
200 GPa 29 x 106 psi
Elongation at Break
28 %
Fatigue Strength
370 MPa 54 x 103 psi
Poisson's Ratio
0.27
Reduction in Area
56 %
Rockwell C Hardness
27
Shear Modulus
80 GPa 12 x 106 psi
Shear Strength
510 MPa 73 x 103 psi
Tensile Strength: Ultimate (UTS)
780 MPa 110 x 103 psi
Tensile Strength: Yield (Proof)
510 MPa 74 x 103 psi
Thermal Properties
Latent Heat of Fusion
300 J/g
Maximum Temperature: Corrosion
450 °C 840 °F
Maximum Temperature: Mechanical
1100 °C 2010 °F
Melting Completion (Liquidus)
1430 °C 2610 °F
Melting Onset (Solidus)
1390 °C 2530 °F
Specific Heat Capacity
480 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
16 W/m-K 9.2 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.1 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.5 % IACS
Otherwise Unclassified Properties
Base Metal Price
17 % relative
Density
7.7 g/cm3 480 lb/ft3
Embodied Carbon
3.4 kg CO2/kg material
Embodied Energy
48 MJ/kg 20 x 103 BTU/lb
Embodied Water
170 L/kg 20 gal/lb
Common Calculations
PREN (Pitting Resistance)
33
Resilience: Ultimate (Unit Rupture Work)
190 MJ/m3
Resilience: Unit (Modulus of Resilience)
640 kJ/m3
Stiffness to Weight: Axial
15 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
28 points
Strength to Weight: Bending
24 points
Thermal Diffusivity
4.3 mm2/s
Thermal Shock Resistance
21 points
Alloy Composition
Among wrought stainless steels, the composition of AISI 312 stainless steel is notable for containing a comparatively high amount of chromium (Cr). Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance.
| Fe | 62.2 to 69.2 | |
| Cr | 24 to 26 | |
| Ni | 5.5 to 6.5 | |
| Mo | 1.2 to 2.0 | |
| Mn | 0 to 2.0 | |
| Si | 0 to 1.0 | |
| N | 0.14 to 0.2 | |
| P | 0 to 0.045 | |
| 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
Duplex Stainless Steels, Iris Alvarez-Armas and Suzanne Degallaix-Moreuil (editors), 2009
Duplex Stainless Steels: Microstructure, Properties and Applications, Robert N. Gunn (editor), 1997
Machining of Stainless Steels and Super Alloys: Traditional and Nontraditional Techniques, Helmi A. Youssef, 2016
ASTM A182: Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service
ASTM A240: Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
Welding Metallurgy of Stainless Steels, Erich Folkhard et al., 2012
Corrosion of Stainless Steels, A. John Sedriks, 1996
ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994
Advances in Stainless Steels, Baldev Raj et al. (editors), 2010