UNS S32750 (Alloy 2507) Stainless Steel
S32750 stainless steel is a duplex stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. S32750 is the UNS number for this material. Alloy 2507 is the common industry name.
It has a fairly low ductility among wrought duplex stainless steels. In addition, it has a moderately high tensile strength and a moderately high base cost.
The graph bars on the material properties cards below compare S32750 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
210 GPa 30 x 106 psi
Elongation at Break
17 %
Fatigue Strength
360 MPa 52 x 103 psi
Poisson's Ratio
0.27
Rockwell C Hardness
28
Shear Modulus
81 GPa 12 x 106 psi
Shear Strength
530 MPa 77 x 103 psi
Tensile Strength: Ultimate (UTS)
860 MPa 130 x 103 psi
Tensile Strength: Yield (Proof)
590 MPa 86 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)
1450 °C 2640 °F
Melting Onset (Solidus)
1400 °C 2560 °F
Specific Heat Capacity
480 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
15 W/m-K 8.7 BTU/h-ft-°F
Thermal Expansion
12 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.2 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.5 % IACS
Otherwise Unclassified Properties
Base Metal Price
21 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
4.1 kg CO2/kg material
Embodied Energy
56 MJ/kg 24 x 103 BTU/lb
Embodied Water
180 L/kg 21 gal/lb
Common Calculations
PREN (Pitting Resistance)
43
Resilience: Ultimate (Unit Rupture Work)
130 MJ/m3
Resilience: Unit (Modulus of Resilience)
860 kJ/m3
Stiffness to Weight: Axial
15 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
31 points
Strength to Weight: Bending
26 points
Thermal Diffusivity
4.0 mm2/s
Thermal Shock Resistance
25 points
Alloy Composition
Among wrought stainless steels, the composition of S32750 stainless steel is notable for containing a comparatively high amount of chromium (Cr) and including copper (Cu). Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance. Copper is used to improve resistance to acids, and to improve formability.
| Fe | 58.1 to 66.8 | |
| Cr | 24 to 26 | |
| Ni | 6.0 to 8.0 | |
| Mo | 3.0 to 5.0 | |
| Mn | 0 to 1.2 | |
| Si | 0 to 0.8 | |
| N | 0.24 to 0.32 | |
| Cu | 0 to 0.5 | |
| P | 0 to 0.035 | |
| C | 0 to 0.030 | |
| S | 0 to 0.020 |
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
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 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
Pressure Vessels: External Pressure Technology, 2nd ed., Carl T. F. Ross, 2011
Corrosion of Stainless Steels, A. John Sedriks, 1996
ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994