UNS N08028 (Alloy 28) Stainless Steel
N08028 stainless steel is a superaustenitic (highly alloyed) stainless steel formulated for primary forming into wrought products. Cited properties are appropriate for the annealed condition. N08028 is the UNS number for this material. Alloy 28 is the common industry name.
It has a moderately high base cost among wrought superaustenitic stainless steels. In addition, it has a moderately high ductility and a moderately high embodied energy.
The graph bars on the material properties cards below compare N08028 stainless steel to: wrought superaustenitic 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 30 x 106 psi
Elongation at Break
45 %
Fatigue Strength
220 MPa 32 x 103 psi
Poisson's Ratio
0.28
Rockwell B Hardness
80
Shear Modulus
80 GPa 12 x 106 psi
Shear Strength
400 MPa 57 x 103 psi
Tensile Strength: Ultimate (UTS)
570 MPa 82 x 103 psi
Tensile Strength: Yield (Proof)
240 MPa 35 x 103 psi
Thermal Properties
Latent Heat of Fusion
320 J/g
Maximum Temperature: Corrosion
460 °C 850 °F
Maximum Temperature: Mechanical
1100 °C 2010 °F
Melting Completion (Liquidus)
1420 °C 2580 °F
Melting Onset (Solidus)
1370 °C 2490 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
12 W/m-K 6.9 BTU/h-ft-°F
Thermal Expansion
16 µm/m-K
Otherwise Unclassified Properties
Base Metal Price
37 % relative
Density
8.1 g/cm3 500 lb/ft3
Embodied Carbon
6.4 kg CO2/kg material
Embodied Energy
89 MJ/kg 38 x 103 BTU/lb
Embodied Water
240 L/kg 28 gal/lb
Common Calculations
PREN (Pitting Resistance)
39
Resilience: Ultimate (Unit Rupture Work)
210 MJ/m3
Resilience: Unit (Modulus of Resilience)
140 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
19 points
Strength to Weight: Bending
19 points
Thermal Diffusivity
3.2 mm2/s
Thermal Shock Resistance
12 points
Alloy Composition
Among wrought stainless steels, the composition of N08028 stainless steel is notable for containing comparatively high amounts of chromium (Cr) and manganese (Mn). Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance. Manganese is used to improve ductility at elevated temperatures. It also permits a higher nitrogen content than would otherwise be possible.
| Fe | 29 to 40.4 | |
| Ni | 30 to 34 | |
| Cr | 26 to 28 | |
| Mo | 3.0 to 4.0 | |
| Mn | 0 to 2.5 | |
| Cu | 0.6 to 1.4 | |
| Si | 0 to 1.0 | |
| C | 0 to 0.030 | |
| P | 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
ASTM B668: Standard Specification for UNS N08028 Seamless Pipe and Tube
ASTM B709: Standard Specification for Iron-Nickel-Chromium-Molybdenum Alloy (UNS N08028) Plate, Sheet, and Strip
Nickel Alloys, Ulrich Heubner (editor), 1998
Corrosion of Austenitic Stainless Steels: Mechanism, Mitigation and Monitoring, H. S. Khatak and B. Raj (editors), 2002
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
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015