ASTM B409 Standard
ASTM B409 specification covers UNS N08120, UNS N08890, UNS N08800, UNS N08810, and UNS N088113 in the form of rolled plate, sheet, and strip. Alloy UNS N08800 is normally employed in service temperatures up to and including 1100°F (593°C). Alloys UNS N08120, UNS N08810, UNS N08811, and UNS N08890 are normally employed in service temperatures above 1100°F (593°C) where resistance to creep and rupture is required, and they are annealed to develop controlled grain size for optimum properties in this temperature range.
Key Structural Differences: N08800 vs. N08810 vs. N08811
While sharing the same base matrix of Nickel (30.0% to 35.0%) and Chromium (19.0% to 23.0%), these three variants are differentiated by tighter microstructural controls to maximize performance within specific heat ranges:
- UNS N08800 (Alloy 800): Optimized for low-to-moderate temperature service up to 593°C (1100°F). It is typically supplied in the mill-annealed state to ensure maximum process corrosion resistance.
- UNS N08810 (Alloy 800H): Specially engineered for service temperatures above 593°C (1100°F) where creep-rupture performance is required. It features a controlled carbon range (0.05% to 0.10%) and is high-temperature solution annealed to achieve a coarse grain size (ASTM No. 5 or coarser).
- UNS N08811 (Alloy 800HT): Further optimized variant of 800H, restricting the combined Aluminum + Titanium content to a narrow window (0.85% to 1.20%) to ensure exceptional long-term creep resistance in extreme environments up to 982°C (1800°F).
Chemical Composition Split (Weight %)
| Element Designation | UNS N08800 (Alloy 800) | UNS N08810 (Alloy 800H) | UNS N08811 (Alloy 800HT) |
| Nickel (Ni) | 30.0 – 35.0 | 30.0 – 35.0 | 30.0 – 35.0 |
| Chromium (Cr) | 19.0 – 23.0 | 19.0 – 23.0 | 19.0 – 23.0 |
| Iron (Fe) | 39.5 min (Balance) | 39.5 min (Balance) | 39.5 min (Balance) |
| Carbon (C) | 0.10 max | 0.05 – 0.10 | 0.06 – 0.10 |
| Aluminum (Al) | 0.15 – 0.60 | 0.15 – 0.60 | 0.25 – 0.60 |
| Titanium (Ti) | 0.15 – 0.60 | 0.15 – 0.60 | 0.25 – 0.60 |
| Al + Ti (Combined) | 0.30 – 1.20 | 0.30 – 1.20 | 0.85 – 1.20 |
SB409 N08800 N08810 N08811 properties
The ASME SB409 specification covers nickel-iron-chromium alloys (UNS N08800), nickel-iron-chromium-cobalt-molybdenum alloys (UNS N08810), and nickel-iron-chromium-molybdenum-copper alloys (UNS N08811) in the form of hot or cold-rolled plates, sheets, and strips.
Resistance Corrosion
These alloys 1.4876 material have exceptional corrosion resistance in environments containing sulfuric acid, hydrochloric acid, and phosphoric acid. They are also resistant to corrosion by seawater, high-temperature steam, and oxidizing gases. ASTM B409 UNS N08800, N08810, and N08811 are known for their high tensile strength, excellent weldability, and creep resistance properties.
Resist High Temperatures
One of the key benefits of these alloys is their ability to withstand high temperatures. Nickel-based alloys like SB409 N08800 Plate can operate at temperatures up to 1,100°C, while SB 409 alloy 800h can withstand even higher temperatures of up to 1,200°C. The most heat-resistant alloy, SB 409 UNS N08811, can operate at temperatures up to 1,315°C.
Applications
These high-temperature resistant Incoloy 800 800H 800HT alloys are used in a wide range of high-temperature applications such as gas turbines, boilers, heat exchangers, and exhaust systems. They are also used in the production of chemical and petrochemical equipment, where they must withstand high-temperature and corrosive environments.
In conclusion, ASME SB 409 UNS N08800, N08810, and N08811 are excellent high-temperature resistant alloys that offer exceptional corrosion resistance and can operate at extreme temperatures. They are widely used in various industries and applications where high-temperature performance is critical.
