UNS S31100 (XM-26) Stainless Steel
S31100 stainless steel is a duplex stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. XM-26 is the ASTM designation for this material. S31100 is the UNS number.
It has the highest tensile strength among wrought duplex stainless steels. In addition, it has the lowest ductility and a moderately high thermal conductivity.
The graph bars on the material properties cards below compare S31100 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
270
Elastic (Young's, Tensile) Modulus
200 GPa 29 x 106 psi
Elongation at Break
4.5 %
Fatigue Strength
330 MPa 48 x 103 psi
Poisson's Ratio
0.27
Rockwell C Hardness
28
Shear Modulus
79 GPa 11 x 106 psi
Shear Strength
580 MPa 84 x 103 psi
Tensile Strength: Ultimate (UTS)
1000 MPa 150 x 103 psi
Tensile Strength: Yield (Proof)
710 MPa 100 x 103 psi
Thermal Properties
Latent Heat of Fusion
300 J/g
Maximum Temperature: Corrosion
470 °C 880 °F
Maximum Temperature: Mechanical
1100 °C 2010 °F
Melting Completion (Liquidus)
1420 °C 2590 °F
Melting Onset (Solidus)
1380 °C 2510 °F
Specific Heat Capacity
480 J/kg-K 0.12 BTU/lb-°F
Thermal Conductivity
16 W/m-K 9.1 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.0 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.4 % IACS
Otherwise Unclassified Properties
Base Metal Price
16 % relative
Density
7.7 g/cm3 480 lb/ft3
Embodied Carbon
3.1 kg CO2/kg material
Embodied Energy
44 MJ/kg 19 x 103 BTU/lb
Embodied Water
170 L/kg 20 gal/lb
Common Calculations
PREN (Pitting Resistance)
26
Resilience: Ultimate (Unit Rupture Work)
40 MJ/m3
Resilience: Unit (Modulus of Resilience)
1240 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
36 points
Strength to Weight: Bending
29 points
Thermal Diffusivity
4.2 mm2/s
Thermal Shock Resistance
28 points
Alloy Composition
Among wrought stainless steels, the composition of S31100 stainless steel is notable for containing a comparatively high amount of chromium (Cr) and including titanium (Ti). Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance. Titanium is used to broadly improve mechanical properties.
| Fe | 63.6 to 69 | |
| Cr | 25 to 27 | |
| Ni | 6.0 to 7.0 | |
| Mn | 0 to 1.0 | |
| Si | 0 to 1.0 | |
| Ti | 0 to 0.25 | |
| C | 0 to 0.060 | |
| 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 A693: Standard Specification for Precipitation-Hardening Stainless and Heat-Resisting Steel Plate, Sheet, and Strip
Duplex Stainless Steels, Iris Alvarez-Armas and Suzanne Degallaix-Moreuil (editors), 2009
Duplex Stainless Steels: Microstructure, Properties and Applications, Robert N. Gunn (editor), 1997
ASTM A959: Standard Guide for Specifying Harmonized Standard Grade Compositions for Wrought Stainless Steels
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