Stainless Steel Coil Tube for Organic Heat Carrier Heating Furnaces
Product Overview
The stainless steel coil tube (Coil Tube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a high-performance tubular component specifically engineered for organic heat carrier (OHC) heating furnace systems. This product represents a critical structural and functional element in industrial thermal energy transfer processes, designed to maximize heat exchange efficiency while maintaining structural integrity under prolonged thermal cycling conditions.
Coil tubes are arranged in helical configurations within furnace chambers, facilitating optimal heat transfer between the heat source and the circulating organic heat carrier fluid. The helical geometry provides a significantly larger surface area-to-volume ratio compared to straight tube designs, enabling superior thermal performance and compact system footprints.
Material & Properties
Coil tubes are fabricated from high-grade austenitic stainless steel grades selected for their exceptional resistance to thermal fatigue, oxidation, and corrosion under aggressive operating environments. The primary material grades include:
- 304 Stainless Steel (UNS S30400) – General-purpose grade with excellent formability and resistance to moderate temperatures up to 870°C (1,598°F).
- 321 Stainless Steel (UNS S32100) – Titanium-stabilized grade offering superior resistance to intergranular corrosion and sustained service temperatures up to 900°C (1,652°F).
- 310S Stainless Steel (UNS S31008) – High-temperature grade suitable for continuous service up to 1,150°C (2,094°F) with exceptional oxidation resistance.
- 316L Stainless Steel (UNS S31603) – Molybdenum-enhanced grade for applications requiring resistance to chloride-induced pitting and crevice corrosion.
Key mechanical and thermal properties include:
- Tensile strength: 515–750 MPa (depending on grade and condition)
- Yield strength: 205–310 MPa
- Elongation at break: ≥35%
- Thermal conductivity: 14–16 W/(m·K) at 25°C
- Linear thermal expansion coefficient: 16–18 × 10⁻⁶/K
- Maximum continuous service temperature: up to 1,150°C (grade-dependent)
Specifications
| Parameter | Specification |
|---|---|
| Product Category | Coil Tube (盘管) for Organic Heat Carrier Systems |
| Outer Diameter (OD) | 12 mm – 159 mm (customizable) |
| Wall Thickness | 1.0 mm – 6.0 mm |
| Coil Pitch (Helix Spacing) | 15 mm – 50 mm (configurable per thermal design) |
| Coil Diameter | 100 mm – 3,000 mm |
| Tube Length per Coil | 5 m – 100 m (adjustable) |
| Material Grades | 304, 304L, 316L, 321, 310S, 347H (ASTM/ASME) |
| Surface Finish | No. 2B, BA (Bright Annealed), or 240–320 grit ground |
| End Condition | Plain, beveled, threaded, or flanged connections |
| Operating Temperature Range | −50°C to 1,150°C (grade-dependent) |
| Operating Pressure | Up to 1.6 MPa (design-dependent) |
| Heat Carrier Fluids | Thermal oil, synthetic heat transfer fluids, molten salts |
| Applicable Standards | ASTM A213, ASTM A269, ASME B31.3, EN 10216-5 |
| Manufacturing Standard | ISO 9001:2015 certified production |
Manufacturing Process
The coil tube manufacturing process at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous multi-stage procedure to ensure dimensional accuracy, metallurgical soundness, and thermal performance:
- Raw Material Selection and Inspection – Ingot certification verification, chemical composition analysis (spectroscopic testing), and mechanical property validation per ASTM standards.
- Hot Rolling / Cold Drawing – Seamless tubes are produced via hot piercing or cold drawing methods to achieve precise wall thickness and dimensional tolerances (±0.05 mm).
- Heat Treatment (Solution Annealing) – Tubes are annealed at 1,050–1,150°C followed by rapid quenching to achieve a uniform austenitic microstructure free of residual stresses.
- Coil Forming (Helical Bending) – Precision CNC-controlled coil forming machines shape the straight tubes into helical configurations with controlled pitch, diameter, and spring-back compensation.
- Post-Forming Heat Treatment – Stress-relief annealing to eliminate residual stresses introduced during the coiling process, ensuring dimensional stability during thermal cycling.
- Surface Treatment – Pickling and passivation to remove scale and restore chromium oxide protective layer; optional bright annealing (BA) for enhanced surface finish.
- Non-Destructive Testing (NDT) – 100% eddy current testing (ECT) for wall thickness and surface defect detection; hydrostatic pressure testing per ASTM A751.
- Final Dimensional Inspection – Laser-based measurement of coil diameter, pitch uniformity, and total length to confirm compliance with engineering drawings.
Applications
Stainless steel coil tubes are integral components in a wide range of industrial heating and thermal processing systems:
- Organic Heat Carrier (OHC) Heating Furnaces – Primary application where coil tubes serve as heat exchangers for thermal oil systems operating at 250–350°C.
- Industrial Drying and Curing Systems – Paper manufacturing, textile processing, and food dehydration facilities requiring uniform radiant heat distribution.
- Chemical Process Heating – Reactor jacket heating, distillation column reboilers, and process fluid preheating in petrochemical and pharmaceutical plants.
- Power Generation Auxiliary Systems – Feedwater heaters and economizer sections in combined heat and power (CHP) installations.
- Plastic and Rubber Processing – Extruder barrel heating elements and mold temperature control systems.
- Municipal Heating Systems – District heating distribution networks utilizing low-temperature organic heat transfer fluids.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management systems and product certifications to ensure consistent performance and regulatory compliance:
- ISO 9001:2015 – Quality Management System certification covering all manufacturing operations.
- ISO 14001:2015 – Environmental Management System certification demonstrating sustainable production practices.
- CE Marking (EU) – Compliance with European Pressure Equipment Directive (PED 2014/68/EU) for pressure-containing components.
- ASTM Material Certification – Full chemical and mechanical test reports per ASTM A751/A751M for each production lot.
- TÜV Inspection – Third-party verification of manufacturing processes and product conformity.
- ASME "U" Stamp – Authorized manufacturer designation for pressure vessel and piping components where applicable.
- Mill Test Certificates (MTC) – EN 10204 Type 3.1 certificates provided with every shipment.
Unique Selling Points
- Enhanced Thermal Efficiency Design – Optimized helical geometry with variable pitch configurations that improve convective heat transfer coefficients by up to 30% compared to conventional straight-tube designs, as validated through CFD (Computational Fluid Dynamics) simulations.
- Superior Thermal Fatigue Resistance – Custom heat treatment protocols ensuring minimum 50,000 thermal cycling endurance without cracking or deformation.
- Custom Engineering Capability – Full design flexibility in coil diameter, pitch, tube specification, and end connections to match specific furnace layouts and thermal requirements.
- Extended Service Life – 310S and 321 grade options providing operational lifetimes exceeding 15 years in continuous thermal oil service environments.
- Integrated Supply Chain – End-to-end manufacturing from raw material procurement through coil forming and final testing, ensuring full traceability and quality control.