UNS S31730 Stainless Steel
S31730 stainless steel is an austenitic stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition.
It has a fairly low tensile strength among wrought austenitic stainless steels. In addition, it has a moderately high embodied energy and a moderately high base cost.
The graph bars on the material properties cards below compare S31730 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
40 %
Fatigue Strength
170 MPa 25 x 103 psi
Poisson's Ratio
0.28
Rockwell B Hardness
78
Shear Modulus
77 GPa 11 x 106 psi
Shear Strength
370 MPa 54 x 103 psi
Tensile Strength: Ultimate (UTS)
540 MPa 79 x 103 psi
Tensile Strength: Yield (Proof)
200 MPa 29 x 103 psi
Thermal Properties
Latent Heat of Fusion
290 J/g
Maximum Temperature: Corrosion
420 °C 780 °F
Maximum Temperature: Mechanical
990 °C 1820 °F
Melting Completion (Liquidus)
1430 °C 2610 °F
Melting Onset (Solidus)
1390 °C 2530 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Expansion
16 µm/m-K
Otherwise Unclassified Properties
Base Metal Price
24 % relative
Density
8.0 g/cm3 500 lb/ft3
Embodied Carbon
4.6 kg CO2/kg material
Embodied Energy
63 MJ/kg 27 x 103 BTU/lb
Embodied Water
180 L/kg 21 gal/lb
Common Calculations
PREN (Pitting Resistance)
30
Resilience: Ultimate (Unit Rupture Work)
170 MJ/m3
Resilience: Unit (Modulus of Resilience)
99 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
19 points
Strength to Weight: Bending
18 points
Thermal Shock Resistance
12 points
Alloy Composition
Among wrought stainless steels, the composition of S31730 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 | 52.4 to 61 | |
| Cr | 17 to 19 | |
| Ni | 15 to 16.5 | |
| Cu | 4.0 to 5.0 | |
| Mo | 3.0 to 4.0 | |
| Mn | 0 to 2.0 | |
| Si | 0 to 1.0 | |
| N | 0 to 0.045 | |
| P | 0 to 0.040 | |
| C | 0 to 0.030 | |
| S | 0 to 0.010 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
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 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
ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994
Advances in Stainless Steels, Baldev Raj et al. (editors), 2010