Stainless Steel Coil Tube — Coiltube for Heat Exchange & Ice Melting Applications
Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered continuous tube formed into a helical coil configuration, specifically designed for thermal management applications including ice melting troughs, heat exchangers, and refrigeration systems. This product series (Catalog No. 1232) has been extensively studied in academic research concerning the Temperature Distribution Characteristics in Coil-Type External Ice Melting Troughs, validating its superior thermal performance and structural reliability under cryogenic and sub-zero operating conditions.
The coil tube serves as the core heat transfer element in external ice melting trough systems, where it circulates a heat transfer medium (typically water, brine, or glycol solution) to facilitate controlled ice melting on external surfaces. The helical geometry maximizes the heat exchange surface area within a compact footprint, enabling efficient thermal energy transfer while maintaining structural integrity under cyclic thermal loading.
Material & Properties
The coil tube is fabricated from high-grade stainless steel conforming to internationally recognized metallurgical standards. The primary material grades offered include:
- AISI 304 (UNS S30400 / 1.4301) — General-purpose austenitic stainless steel offering excellent corrosion resistance and formability.
- AISI 316 (UNS S31600 / 1.4401) — Molybdenum-enhanced austenitic grade providing superior resistance to chloride-induced pitting and crevice corrosion.
- AISI 316L (UNS S31603 / 1.4404) — Low-carbon variant of 316L, suitable for cryogenic service and welding applications.
- AISI 321 (UNS S32100 / 1.4541) — Titanium-stabilized grade for elevated-temperature applications.
| Property | Specification |
|---|---|
| Density | 8.00 g/cm³ (7990 kg/m³) |
| Thermal Conductivity | 14.2–16.3 W/(m·K) at 20°C |
| Thermal Expansion Coefficient | 16.0–17.5 × 10⁻⁶ /K (20–100°C) |
| Specific Heat Capacity | 498 J/(kg·K) at 20°C |
| Yield Strength (0.2% Offset) | ≥ 205 MPa (AISI 304, annealed) |
| Tensile Strength | 515–720 MPa |
| Elongation at Break | ≥ 40% |
| Operating Temperature Range | −196°C to +870°C |
| Corrosion Resistance | Excellent in atmospheric, aqueous, and mildly corrosive environments |
| Surface Finish | 2B (cold-rolled), BA (Bright Annealed), No. 4 Brushed, or Custom |
Specifications
| Parameter | Specification Range |
|---|---|
| Outer Diameter (OD) | 6 mm – 108 mm |
| Wall Thickness | 0.5 mm – 6.0 mm |
| Coil Inner Diameter (CID) | 50 mm – 1500 mm |
| Coil Length (per coil) | Up to 2000 m (continuous) |
| Coil Pitch | Configurable: 10 mm – 150 mm |
| Number of Turns | Configurable per application requirements |
| Tube Configuration | Single-helix, double-helix, serpentine, or custom multi-pass |
| End Treatment | Plain end, beveled end, threaded end, or flanged connection |
| Tolerance on OD | ± 0.1 mm (standard); ± 0.05 mm (precision grade) |
| Tolerance on Wall Thickness | ± 10% of nominal |
| Material Standard | ASTM A269, ASTM A270, ASME SA-269, EN 10217-7, GB/T 12771 |
| Heat Treatment | Solution annealed (1040–1120°C, water or air quenched) |
| Maximum Working Pressure | Up to 4.0 MPa (depending on OD and wall thickness) |
| Surface Roughness (Ra) | ≤ 1.6 μm (standard); ≤ 0.4 μm (polished) |
Manufacturing Process
The production of stainless steel coil tubes at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous multi-stage manufacturing process ensuring dimensional accuracy, metallurgical quality, and mechanical integrity:
- Raw Material Sourcing & Inspection: Cold-rolled stainless steel coils are sourced from certified mills and subjected to incoming quality control (IQC), including spectroscopic analysis (PMI — Positive Material Identification), visual inspection, and dimensional verification.
- Coil Slitting & Leveling: Master coils are slit to the required width and cold-rolled into flat strip stock. The strip is then leveled to eliminate residual stresses and ensure flatness within tolerance.
- Tube Forming (Roll Forming): The flat strip is passed through a series of precision-formed rollers in a progressive roll-forming machine. Each roller station progressively bends the strip into the final circular cross-section. The forming process is performed at room temperature to preserve the material's cold-worked strength characteristics.
- Welding (if applicable): For welded coil tubes, the longitudinal seam is welded using Auto-Capillary TIG (Gas Tungsten Arc Welding) with inert gas shielding (Argon, 99.99% purity). The welding parameters are precisely controlled to minimize heat-affected zone (HAZ) distortion and ensure a fully fused, corrosion-resistant seam. Alternatively, seamless coil tubes are produced via cold-drawing or cold-rolling processes.
- Helical Coiling: The formed tube is fed through a precision coiling machine that wraps the tube into the specified helical geometry. The coiling process is controlled by CNC (Computer Numerical Control) to maintain consistent pitch, coil diameter, and number of turns.
- Heat Treatment (Solution Annealing): Coiled tubes are solution-annealed at 1040–1120°C followed by controlled cooling to restore full austenitic structure, relieve residual stresses, and achieve maximum ductility and corrosion resistance.
- Pickling & Passivation: The surface is cleaned via acid pickling (typically nitric-hydrofluoric acid blend or citric acid for environmental compliance) to remove oxide scale. A subsequent passivation treatment (nitric acid or citric acid) establishes a stable chromium oxide passive layer, enhancing corrosion resistance.
- Surface Finishing: Depending on the application, tubes may undergo electropolishing, mechanical polishing, or brushing to achieve the specified surface finish.
- Pressure Testing & Non-Destructive Testing (NDT): Every coil tube is hydrostatically pressure-tested to 1.5× the maximum working pressure for a minimum hold time of 30 seconds. Additionally, eddy current testing (ECT) and dye penetrant testing (PT) are performed to detect surface and near-surface defects.
- Final Inspection & Packaging: Dimensional verification, visual inspection, and material certification documentation are completed. Tubes are packaged in protective wrapping with end caps and shipped on wooden pallets or in steel drums.
Applications
The stainless steel coil tube is a versatile component deployed across a wide range of industrial and commercial applications:
- Ice Melting Trough Systems: As validated by academic research on temperature distribution in coil-type external ice melting troughs, the coil tube serves as the primary heat transfer medium in de-icing systems for aircraft runways, industrial storage tanks, and food processing facilities. The helical configuration ensures uniform temperature distribution along the trough surface, preventing localized thermal stress and achieving consistent ice melt rates.
- Heat Exchangers: Compact coil-type heat exchangers for HVAC (Heating, Ventilation, and Air Conditioning) systems, refrigeration plants, and process cooling applications.
- Refrigeration & Cryogenic Systems: Evaporator coils and condenser coils in commercial refrigeration units, cold storage facilities, and cryogenic equipment operating at temperatures as low as −196°C.
- Food & Beverage Industry: Pasteurization systems, brewing equipment, dairy processing coils, and sanitary-grade heat transfer applications where hygienic surface finishes are mandated.
- Pharmaceutical Industry: Clean-in-place (CIP) systems, reactor heating/cooling coils, and process piping in GMP (Good Manufacturing Practice) environments.
- Chemical Processing: Corrosion-resistant heat transfer coils for aggressive chemical environments, distillation columns, and reactor jacket systems.
- Power Generation: Boiler economizer tubes, condenser tubes, and waste heat recovery systems in thermal power plants.
- Automotive & Aerospace: Radiator cores, fuel system cooling coils, and thermal management components in high-performance vehicles and aerospace systems.
- Marine & Offshore: Seawater heat exchangers, ballast water treatment systems, and shipboard refrigeration coils requiring resistance to saltwater corrosion.
- Building Services: Underfloor heating coils, radiant heating systems, and domestic hot water generation coils.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications and complies with the following international standards:
- ISO 9001:2015 — Quality Management Systems certification, demonstrating systematic commitment to quality and customer satisfaction.
- ISO 14001:2015 — Environmental Management Systems certification, ensuring environmentally responsible manufacturing practices.
- ISO 45001:2018 — Occupational Health and Safety Management Systems certification.
- ASME BPV Section VIII — Compliance with the American Society of Mechanical Engineers Boiler and Pressure Vessel Code for pressure-containing equipment.
- EN 10204 3.1 / 3.2 — Material certification per European standard, including third-party inspection (3.2) for critical applications.
- NADCAP — National Aerospace and Defense Contractors Accreditation Program (where applicable for aerospace supply chain).
- CE Marking (EU) — Conformity with European directives including the Pressure Equipment Directive (PED 2014/68/EU).
- NSF/ANSI 61 — Drinking water system components certification (for food-grade and potable water applications).
- 3-A Sanitary Standards — Compliance with the International Sanitary Joint Committee standards for dairy, food, and beverage processing equipment.
- Material Traceability: Full mill test certificates (MTC), heat number traceability, and chemical/mechanical test reports provided with every shipment.
Unique Selling Points
- Academically Validated Performance: The coil tube design has been rigorously studied in peer-reviewed research on temperature distribution in coil-type external ice melting troughs, providing empirical data-backed assurance of thermal performance and uniformity.
- Precision CNC Coiling: Computer-controlled coiling ensures repeatable, dimensionally accurate coil geometry with consistent pitch and turn count — critical for predictable heat transfer performance.
- Wide Material Grade Selection: Availability in multiple stainless steel grades (304, 316, 316L, 321, and custom alloys) allows precise material selection tailored to specific corrosion, temperature, and mechanical requirements.
- End-to-End Manufacturing Control: Vertical integration from strip sourcing through coiling, heat treatment, surface finishing, and testing ensures consistent quality and reduced supply chain risk.
- Custom Engineering Capability: Flexible configuration options including single-helix, double-helix, serpentine, and multi-pass coil geometries with customizable pitch, diameter, and end treatments to meet application-specific design requirements.
- Superior Cryogenic Performance: Maintains full mechanical properties and fracture toughness at temperatures as low as −196°C, making it ideal for cryogenic and sub-zero applications where carbon steel would become brittle.
- Long Service Life & Low Maintenance: Exceptional corrosion resistance eliminates the need for protective coatings or cathodic protection, resulting in decades of reliable service with minimal maintenance intervention.
- Hygienic Surface Options: Electropolished surfaces with Ra ≤ 0.4 μm meet the most stringent sanitary requirements for food, pharmaceutical, and biotechnology applications.
- Comprehensive Quality Documentation: Every product is accompanied by full traceability documentation, including mill certificates, chemical analysis reports, mechanical test results, and pressure test records.
Engineering Note: The helical coil geometry of this product creates a naturally enhanced turbulence regime within the tube bore, increasing the internal heat transfer coefficient by 20–40% compared to equivalent straight-tube configurations. This passive enhancement, combined with the high thermal conductivity of austenitic stainless steel, results in compact and highly efficient thermal management solutions. The temperature distribution characteristics documented in academic research confirm that coil-type configurations achieve more uniform surface temperatures along the trough length, reducing thermal gradients and minimizing the risk of thermal fatigue cracking at connection points.
Technical Support & Ordering Information
Wenzhou Jixing Metal Materials Co., Ltd. provides comprehensive technical support including:
- Thermal performance modeling and Finite Element Analysis (FEA) for custom coil tube designs.
- Material selection guidance based on application-specific operating conditions.
- Prototype fabrication and performance validation testing.
- Long-term supply agreements with guaranteed material quality and lead time commitments.
- On-site installation guidance and post-delivery technical consulting.
For detailed quotations, custom engineering proposals, or technical inquiries, please contact the sales and engineering team at Wenzhou Jixing Metal Materials Co., Ltd. with your specific application requirements, operating parameters, and applicable standards.