UNS S81921 Stainless Steel
S81921 stainless steel is a duplex stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. It has a moderately low tensile strength and a moderately high ductility among wrought duplex stainless steels.
The graph bars on the material properties cards below compare S81921 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
260
Elastic (Young's, Tensile) Modulus
200 GPa 29 x 106 psi
Elongation at Break
29 %
Fatigue Strength
370 MPa 54 x 103 psi
Poisson's Ratio
0.28
Rockwell C Hardness
27
Shear Modulus
79 GPa 11 x 106 psi
Shear Strength
460 MPa 67 x 103 psi
Tensile Strength: Ultimate (UTS)
710 MPa 100 x 103 psi
Tensile Strength: Yield (Proof)
500 MPa 73 x 103 psi
Thermal Properties
Latent Heat of Fusion
290 J/g
Maximum Temperature: Corrosion
430 °C 800 °F
Maximum Temperature: Mechanical
990 °C 1810 °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
15 W/m-K 8.5 BTU/h-ft-°F
Thermal Expansion
13 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
14 % relative
Density
7.7 g/cm3 480 lb/ft3
Embodied Carbon
2.9 kg CO2/kg material
Embodied Energy
41 MJ/kg 18 x 103 BTU/lb
Embodied Water
150 L/kg 18 gal/lb
Common Calculations
PREN (Pitting Resistance)
28
Resilience: Ultimate (Unit Rupture Work)
180 MJ/m3
Resilience: Unit (Modulus of Resilience)
630 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
25 points
Strength to Weight: Bending
23 points
Thermal Diffusivity
4.0 mm2/s
Thermal Shock Resistance
20 points
Alloy Composition
Among wrought stainless steels, the composition of S81921 stainless steel is notable for containing comparatively high amounts of manganese (Mn) and chromium (Cr). Manganese is used to improve ductility at elevated temperatures. It also permits a higher nitrogen content than would otherwise be possible. Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance.
| Fe | 66.7 to 75.9 | |
| Cr | 19 to 22 | |
| Mn | 2.0 to 4.0 | |
| Ni | 2.0 to 4.0 | |
| Mo | 1.0 to 2.0 | |
| Si | 0 to 1.0 | |
| N | 0.14 to 0.2 | |
| P | 0 to 0.040 | |
| 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
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
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
Advances in Stainless Steels, Baldev Raj et al. (editors), 2010