Incoloy 800H Coil Tube Heater — Technical Specification
Product No.: 396 | Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd. | Category: Literature Learning / Advanced Alloy Coil Tube Systems
1. Product Overview
The Incoloy 800H Coil Tube Heater is a high-performance thermal exchange component engineered from the nickel-chromium-iron superalloy Incoloy 800H (UNS N08810). Designed for continuous operation in extreme thermal environments, this coil tube assembly serves as a critical heating element within industrial heat exchangers, reactor furnaces, and process heating systems. The coil tube geometry maximizes the surface-area-to-volume ratio, enabling efficient radiative and convective heat transfer under conditions where conventional stainless steel materials would suffer catastrophic degradation.
Wenzhou Jixing Metal Materials Co., Ltd. specializes in the fabrication of precision-wound coil tubes using advanced forming techniques and rigorous metallurgical controls. The Incoloy 800H variant is specifically formulated to resist high-temperature oxidation, thermal cycling fatigue, and sulfidation corrosion, making it the preferred choice for petrochemical, power generation, and specialty chemical processing applications.
2. Material & Properties
2.1 Base Alloy Composition (Incoloy 800H / UNS N08810)
| Element | Composition (wt%) | Element | Composition (wt%) |
|---|---|---|---|
| Nickel (Ni) | Balance (≥50.0) | Carbon (C) | ≤0.08 |
| Chromium (Cr) | 19.0 – 23.0 | Sulfur (S) | ≤0.03 |
| Iron (Fe) | 39.0 – 45.0 | Phosphorus (P) | ≤0.035 |
| Manganese (Mn) | ≤1.0 | Silicon (Si) | ≤0.50 |
| Copper (Cu) | 1.0 – 2.0 | Aluminum (Al) | 0.15 – 0.60 |
| Chromium (Cr, min) | — | Titanium (Ti) | 0.01 – 0.15 |
2.2 Key Mechanical & Thermal Properties
| Property | Specification |
|---|---|
| Tensile Strength (at 20°C / 68°F) | ≥ 515 MPa (74.7 ksi) |
| Yield Strength (0.2% Offset, at 20°C) | ≥ 205 MPa (29.7 ksi) |
| Elongation (at 20°C) | ≥ 30% |
| Maximum Continuous Service Temperature | 1100°C (2012°F) |
| Thermal Conductivity (at 100°C) | 11.4 W/(m·K) |
| Thermal Expansion Coefficient (20–100°C) | 13.1 × 10⁻⁶ /°C |
| Density | 8.12 g/cm³ |
| Modulus of Elasticity (at 20°C) | 200 GPa (29 × 10⁶ psi) |
| Creep Resistance | Superior up to 980°C (1800°F) |
2.3 Corrosion & Oxidation Resistance
- High-Temperature Oxidation: Incoloy 800H exhibits exceptional resistance to cyclic oxidation in air and sulfur-bearing atmospheres up to 1000°C, owing to its controlled carbon and sulfur content and the presence of aluminum and titanium stabilizers.
- Sulfidation Resistance: Superior performance in H₂S-containing environments compared to Incoloy 800, making it ideal for refinery and petrochemical service.
- Creep Strength: Enhanced long-term creep resistance at elevated temperatures (above 800°C) due to reduced carbon and sulfur levels, minimizing intergranular carbide precipitation.
- Thermal Fatigue: The alloy maintains structural integrity under repeated thermal cycling, a critical requirement for coil tube heater applications involving start-up and shutdown transients.
3. Specifications
| Parameter | Specification | Notes |
|---|---|---|
| Material Grade | Incoloy 800H (UNS N08810) | ASTM B407 / B463 compliant |
| Tube Form | Coil (helical winding) | Continuous or segmented coil configurations |
| Outer Diameter (OD) | 12.7 mm – 50.8 mm (½" – 2") | Custom diameters available |
| Wall Thickness | 0.5 mm – 3.0 mm (0.020" – 0.118") | Tolerance: ±10% |
| Coil Pitch | 15 mm – 80 mm (adjustable) | Determined by heat flux requirements |
| Coil Length (Unwound) | Up to 50 m per continuous coil | Segmented coils for larger assemblies |
| Surface Finish | Pickled & Passivated (P&P) | Ra ≤ 0.8 μm |
| End Treatment | Plain end / Beveled / Flanged / Threaded | Per customer specification |
| Operating Pressure | Up to 4.0 MPa (580 psi) | Dependent on OD, wall thickness, and temperature |
| Maximum Operating Temperature | 1100°C (2012°F) | Continuous duty rating |
| Minimum Operating Temperature | −196°C (−320°F) | Cryogenic capability verified |
| Winding Tolerance | ±0.5 mm (diameter), ±1.0 mm (pitch) | CNC-controlled winding |
| Heat Treatment | Solution Annealed (1050–1150°C, water quench) | Optional: Stress-relieved per ASTM B906 |
| Applicable Standards | ASTM B407, B463, B906; ASME BPV VIII | EN 10216-4; JIS H 4051 |
4. Manufacturing Process
The fabrication of Incoloy 800H coil tube heaters at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous, multi-stage manufacturing protocol designed to ensure metallurgical integrity, dimensional precision, and long-term service reliability.
4.1 Process Flowchart Overview
- Raw Material Procurement & Certification: Incoloy 800H seamless tubes are sourced from certified mills (e.g., Special Metals, Outokumpu, or equivalent) with full mill test certificates (MTC) conforming to ASTM B407/B463. Each heat lot undergoes spectroscopic verification of chemical composition.
- Incoming Inspection: Tubes are inspected for surface defects, dimensional conformity, and wall thickness uniformity using ultrasonic testing (UT) and eddy current (ET) methods. Visual inspection follows ASTM E1025 guidelines.
- Pre-Forming Annealing: Tubes are solution-annealed at 1050–1150°C followed by controlled water quenching to relieve residual stresses from prior forming operations and ensure a uniform austenitic microstructure.
- Precision Coil Winding: The annealed tubes are wound into helical coil geometries using CNC-controlled winding machines. The winding process employs calibrated mandrels and tension-control systems to maintain uniform pitch, consistent tube-to-tube spacing, and minimal cold-work deformation. Winding parameters (pitch, diameter, number of turns) are determined by thermal design calculations.
- Post-Winding Stress Relief: Wound coils undergo a controlled stress-relief anneal at 870–980°C (1598–1796°F) for a minimum of 2 hours per inch of wall thickness, followed by furnace cooling. This eliminates residual stresses introduced during winding and stabilizes the coil geometry.
- End Fabrication & Fitting: Coil ends are machined, beveled, or flanged per customer specifications. Welding (where applicable) is performed using matching filler metals (e.g., Incoloy 800H wire) in accordance with ASME Section IX, Qualification of Welding Procedures.
- Pickling & Passivation: Coils are subjected to acid pickling (HNO₃/HF mixture) to remove oxide scales, followed by passivation treatment to restore the protective chromium oxide film. Surface roughness is verified to Ra ≤ 0.8 μm.
- Final Quality Inspection: Comprehensive non-destructive testing (NDT) includes dye penetrant testing (PT) for surface defects, ultrasonic testing (UT) for internal discontinuities, and hydrostatic pressure testing at 1.5× the maximum design pressure. Dimensional verification is performed using laser scanning or coordinate measurement systems.
- Packaging & Documentation: Coils are packaged in protective crates with moisture-absorbing desiccants. Each shipment is accompanied by a comprehensive quality dossier including MTCs, NDT reports, dimensional certificates, and heat treatment records.
4.2 Critical Manufacturing Considerations
- Microstructure Control: The solution-annealed austenitic structure of Incoloy 800H must be maintained throughout fabrication. Excessive cold work during winding (>15% strain) can introduce deformation-induced martensite, compromising corrosion resistance and ductility.
- Welding Metallurgy: Welding of Incoloy 800H requires strict control of heat input (limited to 0.5–1.5 kJ/mm) to prevent grain growth and intergranular sensitization. Pre-heating is generally not required but post-weld stress relief is recommended.
- Dimensional Stability: The thermal expansion coefficient of Incoloy 800H (13.1 × 10⁻⁶ /°C) necessitates precise engineering of expansion loops and support structures in the final heater assembly to prevent thermal stress-induced failure.
5. Applications
The Incoloy 800H Coil Tube Heater finds extensive application across industries requiring reliable heat transfer in aggressive, high-temperature environments:
5.1 Petrochemical & Refining
- Catalytic reforming unit heater tubes and reboiler coil elements
- FCC (Fluid Catalytic Cracking) regenerator waste heat recovery coils
- Hydrotreating and hydrocracking process heaters
- Sulfur recovery unit thermal oxidizer tubes
5.2 Power Generation
- Boiler and superheater tube assemblies in fossil-fuel-fired power plants
- Waste heat boiler (WHRB) coil elements in combined cycle gas turbine (CCGT) plants
- Nuclear power plant auxiliary heating systems (non-nuclear containment)
5.3 Specialty Chemical Processing
- Chlor-alkali process heat exchangers and reactor heater coils
- Polymerization reactor internal heating elements
- Pharmaceutical process heating under GMP-compliant conditions
5.4 Aerospace & Defense
- Jet engine heat recovery systems and afterburner components
- Missile propulsion thermal management coils
5.5 Glass & Ceramics Industry
- Furnace heating elements for glass melting tanks
- Ceramic kiln radiant tube coils
6. Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework ensuring full traceability and compliance with international standards:
6.1 Quality Management Systems
- ISO 9001:2015 — Quality Management System certification for manufacturing processes
- ISO 14001:2015 — Environmental Management System
- ISO 4500