Oxidation Carburization Resistance Incoloy 800H Nickel Iron Chromium Alloy
Incoloy 800H is a nickel-iron-chromium superalloy specifically designed and optimized for exceptional creep and rupture strength at elevated temperatures. Unlike the standard Incoloy 800 grade, Alloy 800H features a controlled carbon content range of 0.05-0.10%, which provides significantly enhanced mechanical stability and performance in the 593°C to 982°C (1100°F to 1800°F) service temperature range.
This austenitic alloy maintains a stable microstructure even after prolonged high-temperature exposure, offering excellent resistance to oxidation, carburization, and sulfidation. The carefully balanced chemistry of 30-35% nickel and 19-23% chromium ensures outstanding corrosion resistance in both high-temperature and aqueous environments. Alloy 800H is commonly supplied to ASTM B409, ASME SB-409, and ASTM B564 specifications, making it a preferred material for critical applications in petrochemical processing, power generation, and industrial furnace components.
- Controlled Carbon Content: 0.05-0.10% carbon optimizes creep and rupture strength
- High-Temperature Performance: Excellent mechanical properties from 593°C to 982°C (1100°F to 1800°F)
- Oxidation & Carburization Resistance: Superior performance in high-temperature atmospheres
- Creep & Rupture Strength: Significantly enhanced compared to standard Alloy 800
- ASTM Grain Size Control: Minimum grain size of ASTM 5 or coarser ensures stability
- Versatile Fabricability: Excellent weldability and formability using standard techniques
| Parameter | Details |
|---|---|
| Product Name | Incoloy 800H / Alloy 800H / Incoloy® 800H |
| UNS Designation | N08810 |
| Werkstoff Number | 1.4876 |
| EN Designation | 1.4958 |
| British Standard | BS 3072NA15 (Plate/Sheet), BS 3073NA15 (Strip), BS 3074NA15 (Seamless Tubes), BS 3075NA15 (Wire), BS 3076NA15 (Rod/Bar) |
| Common Trade Names | Nickelvac 800H, Nickel 800H, Ferrochronin 800H, Nicrofer 3220 |
| Product Forms | Plate, Sheet, Strip, Rod, Bar, Wire, Seamless Pipe, Welded Pipe, Seamless Tube, Welded Tube, Forgings, Forging Stock |
| Supply Condition | Solution Heat Treated (SHT), Annealed |
| Available Dimensions | Sheet/Plate: 0.3mm – 50mm thickness; Tube: 6mm – 219mm OD (custom available) |
| Standard Length | 2000mm, 2438mm, 3000mm, 6000mm (or as required) |
| Custom Sizes | Available upon request |
| Surface Finish | Annealed, Pickled, Descaled, Bright Annealed |
The chemical composition of Incoloy 800H complies with ASTM B408, B409, and B407 standards.
| Element | Content (%) | Notes |
|---|---|---|
| Nickel (Ni) | 30.0 – 35.0 | Provides austenitic stability and corrosion resistance |
| Chromium (Cr) | 19.0 – 23.0 | Enhances oxidation and carburization resistance |
| Iron (Fe) | ≥ 39.5 (balance) | Base element, balances cost and properties |
| Carbon (C) | 0.05 – 0.10 | Controlled range for optimized creep strength |
| Manganese (Mn) | ≤ 1.50 | Aids in hot workability |
| Silicon (Si) | ≤ 1.00 | Improves oxidation resistance |
| Phosphorus (P) | ≤ 0.045 | Minimized to maintain ductility |
| Sulfur (S) | ≤ 0.015 | Controlled for hot workability |
| Aluminum (Al) | 0.15 – 0.60 | Stabilizes against intergranular attack |
| Titanium (Ti) | 0.15 – 0.60 | Stabilizes against intergranular attack |
| Aluminum + Titanium | 0.30 – 1.20 | Combined stabilizer content |
| Copper (Cu) | ≤ 0.75 | Residual element |
| ASTM Grain Size | 5 or coarser | Ensures high-temperature stability |
Actual mill test certificates (EN 10204 3.1) available per batch.
Comparison with 800 and 800HT Grades:
| Element | 800 (N08800) | 800H (N08810) | 800HT (N08811) |
|---|---|---|---|
| Carbon (C) | ≤ 0.10% | 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 | 0.30 – 1.20% | 0.30 – 1.20% | 0.85 – 1.20% |
| Grain Size | Not specified | 5 or coarser | 5 or coarser |
| Key Feature | Standard grade | Controlled carbon | Highest creep strength |
Room Temperature Properties (Annealed / Solution Heat Treated)
| Property | Metric (MPa) | Imperial (ksi) |
|---|---|---|
| Tensile Strength (Rm) | 550 – 750 | 80 – 109 |
| Yield Strength 0.2% Proof (Rp0.2) | 240 – 310 | 35 – 45 |
| Elongation (A) | ≥ 45% | ≥ 45% |
| Hardness (HB) | 140 – 190 | 140 – 190 |
| Density | 7.94 g/cm³ | 0.287 lb/in³ |
| Melting Point | 1350 – 1400°C | 2460 – 2550°F |
| Modulus of Elasticity | 196 GPa | 28.4 x 10³ ksi |
High-Temperature Mechanical Properties (Typical for 800H and 800HT)
| Temperature | Hardness | Tensile Strength | Yield Strength (0.2% Offset) | |||
|---|---|---|---|---|---|---|
| °F | °C | BHN | ksi | MPa | ksi | MPa |
| 80 | 27 | 126 | 77.8 | 536 | 21.7 | 150 |
| 800 | 425 | — | 67.5 | 465 | 18.8 | 130 |
| 1000 | 540 | 90 | 62.7 | 432 | 13.0 | 90 |
| 1200 | 650 | 84 | 54.8 | 378 | 13.5 | 93 |
| 1300 | 705 | 82 | 47.7 | 329 | 15.8 | 109 |
| 1400 | 760 | 74 | 34.2 | 236 | 13.1 | 90 |
Operating Temperature Ranges:
- Incoloy 800 (Standard Grade): Up to approximately 816°C (1500°F)
- Incoloy 800H: 593°C to 982°C (1100°F to 1800°F) — optimized for creep resistance
- Incoloy 800HT: 593°C to 982°C (1100°F to 1800°F) — highest creep rupture strength
Typical Rod & Bar Properties:
- 0.2% Yield Strength: 30 – 60 ksi (205 – 415 MPa)
- Tensile Strength: 75 – 100 ksi (515 – 690 MPa)
- Elongation: 60 – 30%
| Product Form | ASTM | ASME | BS | EN/DIN |
|---|---|---|---|---|
| Rod & Bar | B408 | SB408 | BS 3076NA15 | DIN 17460, EN 10095 |
| Wire | — | — | BS 3075NA15 | — |
| Plate & Sheet | B409, B906 | SB409, SB906 | BS 3072NA15 | DIN 17460, EN 10028-7, EN 10095 |
| Strip | — | — | BS 3073NA15 | — |
| Seamless Tube | B163, B407 | SB163, SB407 | BS 3074NA15 | DIN 17459 |
| Welded Tube | B515 | SB515 | — | — |
| Seamless Pipe | B407, B829 | SB407, SB829 | — | — |
| Welded Pipe | B514, B775 | SB514, SB775 | — | — |
| Forgings | B564 | SB564 | — | — |
| Fittings | B366 | SB366 | — | — |
ASME Code Cases: Case 1325 (All Product Forms), Case 2339 (Plate), Case 1983 (Seamless Pipe & Tubes)
Incoloy 800H is widely used across industries requiring reliable performance in high-temperature and corrosive environments, particularly where creep and rupture resistance are critical:
Petrochemical & Chemical Processing
- Process piping and heat exchangers in refineries and petrochemical plants
- Ammonia effluent coolers and reformers
- Ethylene pyrolysis tubes and cracking furnace components
- Hydrocarbon processing equipment and reformers
- Chemical processing vessels and piping systems
Industrial Heating & Heat Treatment
- Radiant tubes and furnace muffles for industrial heating
- Carburizing fixtures, retorts, and baskets in heat treatment furnaces
- Heating element sheathing and furnace rollers
- Industrial furnace components and hardware
- High-temperature springs and fasteners
Power Generation
- Steam generator tubing in conventional and nuclear power plants
- Superheater and reheater tube support systems
- Nuclear reactor components
- Heat recovery steam generator (HRSG) components
Oil & Gas Industries
- Downhole tubing and components
- Wellhead equipment and valves
- Gas turbine components
Aerospace & Gas Turbines
- Commercial gas turbine engine components
- Combustion chambers and transition ducts
- High-temperature fasteners
Other Critical Applications
- Food processing equipment requiring high-temperature stability
- Electric range heating-element sheathing
- Cryogenic storage tanks
- Pressure vessels
- Thermal processing equipment
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