Seamless Incoloy 800HT Pipe
GZH, a professional Incoloy 800HT seamless pipe manufacturer and supplier based in Wenzhou, China, specializes in the production of high-quality nickel alloy seamless pipes using advanced hot extrusion and precision cold-finishing processes. We supply Incoloy 800HT seamless pipes in a wide range of outer diameters, wall thicknesses, and customized cut-to-length specifications to meet diverse industrial project requirements.
Our Incoloy 800HT seamless pipes are manufactured in compliance with international standards such as ASTM B407 and ASME SB407, ensuring consistent mechanical properties, dimensional accuracy, and long-term reliability under high-temperature service conditions. Each pipe undergoes comprehensive quality inspection, including hydrostatic testing, ultrasonic testing, eddy current testing, and PMI (Positive Material Identification), to guarantee performance integrity.
Widely used in petrochemical processing, heat treatment equipment, power generation plants, furnace components, and high-temperature piping systems, our Incoloy 800HT seamless pipes deliver superior strength and corrosion resistance in demanding environments.
With strict quality control, competitive pricing, and dependable global delivery, GZH has established a strong reputation as a trusted supplier of high-temperature nickel alloy seamless pipes worldwide.
Seamless Incoloy 800HT Pipe (UNS N08811): High-Temperature Creep Excellence
What Is a Seamless Incoloy 800HT Pipe?
ASeamless Incoloy 800HT Pipe is a high-performance, nickel-iron-chromium superalloy piping solution engineered for long-term service in extreme thermal environments. Produced from a single solid billet, this seamless pipe eliminates the risk of weld-seam failure, ensuring maximum structural integrity under high-stress conditions.
The"800HT"(UNS N08811) designation represents the most advanced grade in the 800-series family. It is a dual-certified version of Incoloy 800H with precisely controlled levels of carbon, aluminum, and titanium. When combined with a high-temperature solution annealing heat treatment, 800HT delivers significantly higher creep and stress-rupture properties at temperatures above 1100°F(593°C) compared to standard 800 or 800H grades.
Key Features and Advantages
- Superior Creep-Rupture Strength: The strict control of Al + Ti content (0.85% -1.20%) ensures the highest design allowable stresses for long-term high-temperature service.
- Exceptional Oxidation & Carburization Resistance: High chromium content provides a protective oxide scale, while the nickel content maintains stability in carburizing atmospheres.
- Excellent Metallurgical Stability: Designed to resist embrittlement and maintain ductility even after thousands of hours of service in the 1200°Fto
1600°F range.
- Seamless Reliability: Uniform grain structure and wall thickness provide higher safety margins for high-pressure applications in furnaces and power plants.
- Field-Proven Weldability: Easily welded using matching composition filler metals (e.g., Inconel 82 or 617) with excellent resistance to hot cracking.
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 800HT.
Table 1: Chemical Composition of Incoloy 800HT Under ASTM B407
The composition of Incoloy 800HT is carefully balanced to achieve its superior high-temperature strength and oxidation resistance.
| Grade | Ni | Cu | Fe | Mn | C | Si | S | Cr | Al | Ti | P | Other |
| 800 | 30.00-35.00 | ≤0.75 | ≥39.50 | ≤1.50 | ≤0.10 | ≤1.00 | ≤0.015 | 19.00-23.00 | 0.15-0.60 | 0.15-0.60 | ≤0.045 | - |
| 800H | 30.00-34.00 | ≤0.50 | ≥39.5 | ≤1.50 | ≤0.10 | ≤1.00 | ≤0.015 | 19.00-22.00 | - | 0.75-1.50 | - | - |
| 800HT | 30.00-35.00 | ≤0.75 | ≥39.5 | ≤1.50 | 0.05-0.10 | ≤1.00 | ≤0.015 | 19.00-23.00 | 0.15-0.60 | 0.25-0.60 | ≤0.045 | AL+Ti= 0.85-1.20 |
Table 2: Typical Mechanical Properties of Incoloy 800HT Under ASTM B407
Incoloy 800HT is specifically designed to maintain its strength and shape in high-stress, high-temperature environments.
| Tensile Strength | Yield Strength | Elongation | Hardness |
| ≥ 450 MPa | ≥ 170 MPa | ≥ 30% | ≤ 192 HBW |
Table 3: Typical Physical Properties of Incoloy 800HT Under ASTM B407
These physical properties highlight the material's ability to perform reliably under a wide range of conditions.
| Density | Melting Point | Thermal Expansion | Thermal Conductivity | Modulus of Elasticity | Electrical Resistivity |
| 8.03 g/cm³ | 1357 - 1400 °C approx. | 15.0 µm/m·°C (20-100°C) | 11.2 W/m·K (20°C) | 196 GPa | 1.06 x 10⁻⁶ Ω·m (20°C) |
Table 4: The Standard of ASTM B407 For Seamless Incoloy 800HT Pipe Size Tolerance Chart :
Cold-Finished Pipe and Tube:
| 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% |
Common Industrial Applications
- Petrochemical Processing: Ethylene pyrolysis furnace tubes and convection sections.
- Power Generation: Superheater and reheater tubing in advanced coal-fired and nuclear power plants.
- Thermal Processing: Radiant tubes, retorts, and muffles for industrial heat-treating furnaces.
- Hydrocarbon Processing: Components for steam/hydrocarbon reforming and pigtails.
Incoloy Series Comparison Reference:
| Grade | UNS Number | Primary Advantage |
| Incoloy 800 | N08800 | General corrosion and heat resistance. |
| Incoloy 800H | N08810 | Controlled carbon for improved creep strength. |
| Incoloy 800HT | N08811 | Optimized Al+Ti for maximum high-temp performance. |
| Incoloy 825 | N08825 | Superior resistance to sulfuric and phosphoric acids. |
Precision Manufacturing at Wenzhou Xinzhe Tech
AtWezhou Gang Zhen Hui Pipeline Project And Engineering Co.,Ltd., our 800HT seamless pipes undergo a rigorous multi-step process:
- Controlled Forging: Starting with high-purity billets with optimized chemistry.
- Precision Cold Working: Achieving exact tolerances per ASTM B407 Table 4 (Standard/Close tolerances).
- High-Temp Solution Annealing: Performed at a minimum of 2100°F (1150°C) to ensure grain size control (ASTM No. 5 or coarser), which is critical for creep strength.
- Non-Destructive Testing (NDT): 100% Eddy Current and Ultrasonic testing to verify subsurface integrity.
