What Is a Seamless Incoloy 800H Pipe?
A Seamless Incoloy 800H Pipe is a premium nickel-iron-chromium superalloy piping solution engineered for sustained performance in high-temperature industrial environments. Unlike welded alternatives, our seamless pipes are hot-pierced and cold-finished from a single solid billet, ensuring a uniform grain structure and superior burst pressure resistance.
The”800H”(UNS N08810) variant is specifically designed to bridge the gap between standard alloys and ultra-high-temp superalloys. By precisely controlling the carbon content （0.05% to 0.10%） and applying a specialized solution annealing treatment, Incoloy 800H achieves significantly enhanced creep and stress-rupture strength at service temperatures exceeding 1100∘F （593℃）.
Key Features and Advantages
- Enhanced Creep-Rupture Properties: The controlled chemistry and high-temperature anneal stabilize the grain size (typically ASTM No. 5 or coarser), providing maximum resistance to long-term deformation.
- Oxidation & Carburization Resistance: The high chromium (19% to 23%) and nickel (30% to 35%) content creates a robust protective layer against aggressive flue gases and carburizing atmospheres.
- Structural Integrity under Thermal Cycling: The seamless construction eliminates the Heat Affected Zone (HAZ) vulnerabilities, making it ideal for systems with frequent temperature fluctuations.
- Corrosion Versatility: Beyond heat resistance, it maintains excellent stability in various aqueous environments, resisting stress-corrosion cracking (SCC) better than standard stainless steels.
- Excellent Fabricability: Despite its high strength, 800H maintains good ductility and can be easily welded using standard industrial techniques (GTAW/GMAW).
Technical Specifications & Standards
At WENZHOU XINZHE TECH CO., LTD., our Incoloy 800H pipes are manufactured to meet and exceed global engineering requirements:
- ASTM B407 / ASME SB407: Standard Specification for Nickel-Iron-Chromium Alloy Seamless Pipe and Tube.
- ASTM B829: General requirements for nickel and nickel alloy seamless pipes.
- UNS N08810: Ensuring precise chemical balance for high-temp stability.
Product Specifications and Data
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for Incoloy 800H.
The composition of Incoloy 800H is carefully balanced to achieve its superior high-temperature strength and oxidation resistance.
Incoloy 800H is specifically designed to maintain its strength and shape in high-stress, high-temperature environments.
These physical properties highlight the material’s ability to perform reliably under a wide range of conditions.
Cold-Finished Pipes and Tubes:
| Specified/Calculated Nominal OD (Inches) | Permissible Variation (Inches) | Specified/Calculated Nominal OD (mm) | Permissible Variation (mm) |
| 0.500 to 5⁄8, excl. | ±0.005 | 12.7 to 15.8, excl. | ±0.127 |
| 5⁄8 to 1 1⁄2, incl. | ±0.0075 | 15.8 to 38.1, incl. | ±0.190 |
| Over 1 1⁄2 to 3 1⁄2, incl. | ±0.010 | Over 38.1 to 88.9, incl. | ±0.254 |
| Over 3 1⁄2 to 4 1⁄2, incl. | ±0.015 | Over 88.9 to 114.3, incl. | ±0.381 |
| Over 4 1⁄2 to 6, incl. | ±0.020 | Over 114.3 to 152.4, incl. | ±0.508 |
| Over 6 to 6 5⁄8, incl. | ±0.025 | Over 152.4 to 168.3, incl. | ±0.635 |
| Specified/Calculated Nominal OD (Inches) | Permissible Variation (Inches) | Specified/Calculated Nominal OD (mm) | Permissible Variation (mm) |
| 2 1⁄2 to 5 1⁄2, excl. | ±0.031 | 63.5 to 139.7, excl. | ±0.787 |
| 5 1⁄2 to 9 1⁄4, incl. | ±0.047 | 139.7 to 234.9, incl. | ±1.19 |
| Condition | Specified/Calculated Nominal OD (Inches) | Permissible Variation (Wall Thickness) |
| Cold-Finished | 0.500 to 5⁄8, excl. | ±15.0% |
| 5⁄8 to 4 1⁄2, incl. | ±10.0% | |
| Over 4 1⁄2 to 6 5⁄8, incl. | ±12.5% | |
| Hot-Finished | 2 1⁄2 to 9 1⁄4, incl. | ±12.5% |
Industrial Applications of Seamless Incoloy 800H Pipe
The unique combination of high-temperature creep strength and exceptional oxidation resistance makes Seamless Incoloy 800H (UNS N08810) the preferred alloy for critical thermal processing environments:
Heat Treating & Industrial Furnaces
Essential for radiant tubes, furnace muffles, retorts, and high-temperature fixtures where structural stability is required up to 1500°F(815℃).
Power Generation & Utilities
Widely utilized in superheater and reheater tubing for fossil-fired and nuclear power plants, as well as steam generator components.
Petrochemical & Refining
Ideal for ethylene pyrolysis furnace tubes (pigtails and headers), steam/hydrocarbon reforming, and high-temperature burner components.
Waste-to-Energy
High-durability components for waste incinerators, combustion chambers, and exhaust systems handling aggressive flue gases.
Advanced Manufacturing Process
AtWenzhou Xinzhe Tech, the production of Incoloy 800H seamless alloy steel pipes follows a rigorous, multi-stage metallurgical process to ensure peak performance in extreme service:
1. Precision Heating & Billet Preparation
High-purityUNS N08810 solid billets are heated in a controlled-atmosphere rotary furnace to the optimal forging temperature, ensuring uniform material plasticity.
2. Hot Piercing (Hollow Shell Formation)
A heavy-duty piercing mill drives a precision mandrel through the center of the incandescent billet. This creates a seamless hollow shell, eliminating the structural vulnerabilities found in welded tubing.
3. Cold Drawing & Pilgering (Sizing)
To achieve exacting dimensional tolerances and superior surface density, the hollow shells undergo multiple passes of cold drawing or cold pilgering. This process refines the wall thickness and outside diameter (OD) to meet ASTM B407standards.
4. Solution Annealing (Metallurgical Optimization)
The pipes are subjected to a critical high-temperature solution annealing (typically above 2100°F(1150℃). This step is vital to ensure a coarse grain structure (ASTM No. 5 or coarser), which is the key to Incoloy 800H’s superior creep-rupture strength.
5. Straightening & Finishing
After heat treatment, pipes are precision-straightened and cut to specified lengths. Every pipe undergoes a series of rigorous inspections:
NDT Testing: 100% Eddy Current (ET) and Ultrasonic Testing (UT) to detect subsurface flaws.
Hydrostatic Testing: Verifying pressure containment integrity.
Dimensional Audit: Ensuring compliance with close-tolerance engineering requirements.
