UNS N08800 (Alloy 800) Stainless Steel
N08800 stainless steel is a superaustenitic (highly alloyed) stainless steel formulated for primary forming into wrought products. N08800 is the UNS number for this material. Alloy 800 is the common industry name. Additionally, the British Standard (BS) designation is NA15. And the AFNOR (French) designation is 25NC35-20.
This material is well established: the Further Reading section below cites a number of published standards, and that list is not necessarily exhaustive.
It can have the highest tensile strength among wrought superaustenitic stainless steels. In addition, it can have the lowest ductility and has a moderately low base cost.
The properties of N08800 stainless steel include four common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare N08800 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
Elastic (Young's, Tensile) Modulus
200 GPa 29 x 106 psi
Elongation at Break
4.5 to 34 %
Fatigue Strength
150 to 390 MPa 22 to 56 x 103 psi
Poisson's Ratio
0.28
Shear Modulus
77 GPa 11 x 106 psi
Shear Strength
340 to 580 MPa 49 to 84 x 103 psi
Tensile Strength: Ultimate (UTS)
500 to 1000 MPa 73 to 150 x 103 psi
Tensile Strength: Yield (Proof)
190 to 830 MPa 28 to 120 x 103 psi
Thermal Properties
Curie Temperature
-120 °C -180 °F
Latent Heat of Fusion
300 J/g
Maximum Temperature: Corrosion
490 °C 920 °F
Maximum Temperature: Mechanical
1100 °C 2010 °F
Melting Completion (Liquidus)
1390 °C 2530 °F
Melting Onset (Solidus)
1360 °C 2470 °F
Specific Heat Capacity
480 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
12 W/m-K 6.6 BTU/h-ft-°F
Thermal Expansion
14 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
1.7 % IACS
Electrical Conductivity: Equal Weight (Specific)
1.9 % IACS
Otherwise Unclassified Properties
Base Metal Price
30 % relative
Density
8.0 g/cm3 500 lb/ft3
Embodied Carbon
5.3 kg CO2/kg material
Embodied Energy
76 MJ/kg 33 x 103 BTU/lb
Embodied Water
200 L/kg 24 gal/lb
Common Calculations
PREN (Pitting Resistance)
21
Resilience: Ultimate (Unit Rupture Work)
42 to 160 MJ/m3
Resilience: Unit (Modulus of Resilience)
96 to 1740 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
18 to 35 points
Strength to Weight: Bending
18 to 28 points
Thermal Diffusivity
3.0 mm2/s
Thermal Shock Resistance
13 to 25 points
Alloy Composition
Among wrought stainless steels, the composition of N08800 stainless steel is notable for including aluminum (Al) and titanium (Ti). Aluminum is used to improve oxidation resistance. It can also enhance the effects of heat treatment. Titanium is used to broadly improve mechanical properties.
| Fe | 39.5 to 50.7 | |
| Ni | 30 to 35 | |
| Cr | 19 to 23 | |
| Mn | 0 to 1.5 | |
| Si | 0 to 1.0 | |
| Al | 0.15 to 0.6 | |
| Ti | 0.15 to 0.6 | |
| Cu | 0 to 0.75 | |
| C | 0 to 0.1 | |
| P | 0 to 0.045 | |
| S | 0 to 0.015 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B514: Standard Specification for Welded Nickel-Iron-Chromium Alloy Pipe
ASTM B515: Standard Specification for Welded UNS N08120, UNS N08800, UNS N08810, and UNS N08811 Alloy Tubes
ASTM B409: Standard Specification for Nickel-Iron-Chromium Alloy Plate, Sheet, and Strip
ASTM B407: Standard Specification for Nickel-Iron-Chromium Alloy Seamless Pipe and Tube
ASTM B564: Standard Specification for Nickel Alloy Forgings
EN 10095: Heat resisting steels and nickel alloys
ASM Specialty Handbook: Nickel, Cobalt, and Their Alloys, Joseph R. Davis (editor), 2000
Nickel Alloys, Ulrich Heubner (editor), 1998
ASTM A240: Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
ASTM A959: Standard Guide for Specifying Harmonized Standard Grade Compositions for Wrought Stainless Steels