UNS S31254 (Alloy 254) Stainless Steel
S31254 stainless steel is an austenitic stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. S31254 is the UNS number for this material. Alloy 254 is the common industry name.
This material is well established: the Further Reading section below cites a number of published standards, and that list is not necessarily exhaustive.
It has a moderately low electrical conductivity among wrought austenitic stainless steels. In addition, it has a fairly high base cost and a fairly high embodied energy.
The graph bars on the material properties cards below compare S31254 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
190
Elastic (Young's, Tensile) Modulus
200 GPa 30 x 106 psi
Elongation at Break
40 %
Fatigue Strength
290 MPa 42 x 103 psi
Poisson's Ratio
0.28
Reduction in Area
56 %
Rockwell B Hardness
84
Shear Modulus
80 GPa 12 x 106 psi
Shear Strength
490 MPa 72 x 103 psi
Tensile Strength: Ultimate (UTS)
720 MPa 100 x 103 psi
Tensile Strength: Yield (Proof)
330 MPa 48 x 103 psi
Thermal Properties
Latent Heat of Fusion
300 J/g
Maximum Temperature: Corrosion
420 °C 800 °F
Maximum Temperature: Mechanical
1090 °C 1990 °F
Melting Completion (Liquidus)
1460 °C 2670 °F
Melting Onset (Solidus)
1420 °C 2580 °F
Specific Heat Capacity
460 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
14 W/m-K 8.1 BTU/h-ft-°F
Thermal Expansion
17 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
28 % relative
Density
8.0 g/cm3 500 lb/ft3
Embodied Carbon
5.5 kg CO2/kg material
Embodied Energy
74 MJ/kg 32 x 103 BTU/lb
Embodied Water
190 L/kg 22 gal/lb
Common Calculations
PREN (Pitting Resistance)
44
Resilience: Ultimate (Unit Rupture Work)
240 MJ/m3
Resilience: Unit (Modulus of Resilience)
270 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
25 points
Strength to Weight: Bending
22 points
Thermal Diffusivity
3.8 mm2/s
Thermal Shock Resistance
15 points
Alloy Composition
Among wrought stainless steels, the composition of S31254 stainless steel is notable for including copper (Cu) and containing a comparatively high amount of nickel (Ni). Copper is used to improve resistance to acids, and to improve formability. 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 | 51.4 to 56.3 | |
| Cr | 19.5 to 20.5 | |
| Ni | 17.5 to 18.5 | |
| Mo | 6.0 to 6.5 | |
| Cu | 0.5 to 1.0 | |
| Mn | 0 to 1.0 | |
| Si | 0 to 0.8 | |
| N | 0.18 to 0.22 | |
| P | 0 to 0.030 | |
| C | 0 to 0.020 | |
| S | 0 to 0.010 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM A473: Standard Specification for Stainless Steel Forgings
ASTM A479: Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels
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 A276: Standard Specification for Stainless Steel Bars and Shapes
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
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
Pressure Vessels: External Pressure Technology, 2nd ed., Carl T. F. Ross, 2011
Austenitic Stainless Steels: Microstructure and Mechanical Properties, P. Marshall, 1984