Stainless Steel Coil Tube for External Ice-Melting Trough Systems
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd. | Product Code: JX-CT-1299
1. Product Overview
The JX-CT-1299 Stainless Steel Coil Tube is a precision-engineered coiled tube product designed for advanced thermal management applications, particularly in external ice-melting trough (de-icing channel) systems. Based on extensive experimental research into temperature distribution characteristics within coiled tube configurations, this product leverages optimized coil geometry to achieve uniform heat transfer and efficient ice-melting performance. The coil tube serves as the core heat-exchange element in trough-based de-icing installations, where a heated fluid (typically low-pressure hot water or thermal oil) circulates through the coiled structure to melt accumulated ice layers on exposed surfaces.
Unlike conventional straight-pipe heating elements, the coiled configuration provides significantly greater surface area per unit volume, enabling more compact system design while maintaining superior thermal efficiency. Extensive laboratory and field testing have validated the temperature distribution uniformity across the coil, demonstrating that carefully designed coil pitch and tube diameter ratios minimize thermal gradients and ensure consistent melting performance throughout the trough length.
2. Material & Properties
The coil tube is manufactured from high-grade austenitic stainless steel, selected for its exceptional corrosion resistance, thermal conductivity, and mechanical integrity under cyclic thermal loading conditions typical of ice-melting applications.
- Base Material: AISI 304 (1.4301) or AISI 316L (1.4401) austenitic stainless steel, conforming to ASTM A269 / ASME SA-269 specifications
- Corrosion Resistance: Superior resistance to chlorinated de-icing agents, road salts, and atmospheric pollutants; 316L grade offers enhanced pitting resistance via 2.0–2.5% Ni and 2.0–3.0% Mo content
- Thermal Conductivity: 14.9–16.3 W/(m·K) at 20°C, providing efficient heat transfer from the working fluid to the trough surface
- Operating Temperature Range: −60°C to +350°C, accommodating extreme winter conditions and high-temperature working fluids
- Mechanical Properties: Tensile strength ≥ 515 MPa; Yield strength ≥ 205 MPa; Elongation ≥ 40% (annealed condition)
- Surface Finish: Pickled and passivated (2B finish, Ra ≤ 0.8 μm) or electropolished (Ra ≤ 0.4 μm) for reduced friction and enhanced corrosion resistance
- Non-Magnetic: Austenitic structure ensures non-magnetic properties (μr ≤ 1.05) in annealed condition
3. Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Tube Outer Diameter (OD) | Φ6 mm, Φ8 mm, Φ10 mm, Φ12 mm, Φ16 mm (custom sizes available) | ASTM A269 |
| Wall Thickness | 0.5 mm – 2.0 mm (typical: 0.8 mm – 1.2 mm) | ASTM A269 / ASME SA-269 |
| Coil Diameter (Mean) | 50 mm – 300 mm (configurable per trough geometry) | ISO 4427 |
| Coil Pitch (Center-to-Center Spacing) | 10 mm – 40 mm (optimized for uniform temperature distribution) | Internal design specification |
| Coil Length | 1 m – 50 m (continuous or segmented per application) | Custom |
| Maximum Working Pressure | 1.0 – 4.0 MPa (depending on OD and wall thickness) | ASME B31.3 |
| Hydrostatic Test Pressure | 1.5× maximum working pressure | ASME B31.3 |
| Maximum Flow Velocity | ≤ 3.0 m/s (working fluid) | Engineering practice |
| Surface Tolerance | ±0.05 mm (OD); ±0.05 mm (wall thickness) | ISO 4427 |
| End Preparation | Beveled ends (37.5° ±1°) or plain cut; threaded ends (NPT/BSP) available | ASME B36.10M |
| Coating Options | None (bare stainless); PTFE-lined; Silicone-coated | ASTM F2130 (PTFE) |
| Delivery Form | Coiled on spool; pre-shaped to trough profile; custom bent configurations | — |
4. Manufacturing Process
The production of the JX-CT-1299 coil tube follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, metallurgical integrity, and functional performance:
- Raw Material Inspection: Incoming stainless steel seamless tubes undergo 100% ultrasonic testing (UT) per ASTM A777 and chemical composition verification via optical emission spectrometry (OES) to confirm grade compliance.
- Cold Coil Forming: Tubes are precisely coiled using CNC-controlled coiling machines with calibrated dies to achieve exact mean coil diameter and pitch specifications. The forming process is conducted at controlled ambient temperatures (18–25°C) to minimize work-hardening effects and maintain ductility.
- Stress Relief Annealing: Post-coiling annealing at 1050–1100°C followed by controlled cooling restores full austenitic structure, relieves residual stresses, and ensures dimensional stability during thermal cycling.
- Pickling and Passivation: Tubes are immersed in a mixed acid solution (HNO₃/HF) to remove oxide scale and form a stable chromium oxide passive film (Cr₂O₃), enhancing long-term corrosion resistance.
- Dimensional Verification: Each coil is inspected for OD tolerance, wall thickness uniformity (ultrasonic thickness gauging), and coil geometry accuracy (laser scanning).
- Pressure Testing: Every production lot undergoes hydrostatic pressure testing at 1.5× the rated working pressure, held for a minimum of 30 seconds with zero leakage acceptance criteria.
- Final Quality Inspection (FQI): Comprehensive documentation including material certificates (Mill Test Reports), dimensional reports, and visual inspection records are compiled for each batch.
5. Applications
The JX-CT-1299 Stainless Steel Coil Tube is specifically engineered for the following critical applications:
- External Ice-Melting Trough Systems: Primary application in road de-icing channels, airport runway edge de-icing troughs, and industrial conveyor belt de-icing systems where heated coil tubes embedded within trough structures provide continuous, uniform ice melting
- Airport Runway and Taxiway De-Icing: Integrated coil tube troughs along runway edges for passive de-icing without chemical application
- Highway and Bridge De-Icing Channels: Permanent trough installations along roadways and bridge decks for winter maintenance
- Industrial Process Heating: Heat exchanger coil assemblies in food processing, pharmaceutical manufacturing, and chemical production where stainless steel purity is required
- Refrigeration and Cold Storage Systems: Evaporator coils in cryogenic applications requiring stainless steel construction
- Marine and Offshore Platforms: De-icing and anti-icing systems for marine superstructures in polar and sub-polar operating environments
- Solar Thermal Collectors: Coil tube absorbers in concentrated solar thermal systems
6. Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework ensuring product compliance with international standards:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001:2015 — Environmental Management System certification
- ISO/IEC 17025 — Laboratory testing and calibration competency
- EN 10204 3.1 — Material inspection certificates (Mill Test Reports) provided with every shipment
- CE Marking — Conformity with European directives for pressure equipment (PED 2014/68/EU)
- NACE MR0175 / ISO 15156 — Compliance for sour service applications (316L grade)
- ASTM / ASME — Full compliance with American material and fabrication standards
- GB/T — Chinese national standards compliance for domestic market applications
7. Unique Selling Points
Research-Validated Thermal Performance: The coil tube geometry has been validated through rigorous experimental study of temperature distribution in external ice-melting trough configurations. Research findings confirm that the optimized coil pitch-to-diameter ratio achieves temperature uniformity within ±3°C across the trough surface, significantly outperforming straight-pipe alternatives.
- Superior Thermal Uniformity: Experimental research demonstrates that the coiled configuration provides 25–35% more uniform temperature distribution compared to parallel straight-pipe heating elements of equivalent total length, directly translating to more consistent ice-melting performance across the entire trough surface.
- Compact Design Advantage: Coil tube configurations achieve equivalent heat transfer surface area in 60–70% less installed volume than straight-pipe arrays, reducing system footprint and installation complexity.
- Enhanced Flow Dynamics: The curved geometry induces secondary flow patterns (Dean vortices) within the tube, promoting turbulence at lower Reynolds numbers and improving convective heat transfer coefficients by 15–20% over straight tubes at identical flow rates.
- Reduced Pressure Drop: Despite enhanced heat transfer, the optimized coil geometry maintains manageable pressure drops, with experimental data showing ΔP values 10–15% lower than equivalent-length straight tubes at matched heat flux conditions.
- Thermal Cycling Durability: The combination of austenitic stainless steel and stress-relieved coil geometry provides excellent fatigue resistance under repeated freeze-thaw thermal cycling, with demonstrated service life exceeding 20,000 thermal cycles without degradation.
- Custom Configurations: Flexible manufacturing capability allows tailoring of coil diameter, pitch, length, and end configurations to match specific trough geometries and thermal design requirements.
8. Technical Notes & Recommendations
Based on experimental research into temperature distribution within coiled tube ice-melting troughs, the following engineering recommendations are provided for optimal system design:
- Coil Pitch Optimization: A pitch-to-OD ratio of 3.0–5.0 is recommended for balanced thermal uniformity and flow resistance in ice-melting trough applications.
- Working Fluid Selection: Low-pressure hot water (40–70°C) is the preferred working fluid, offering the best balance of safety, efficiency, and operating cost.
- Flow Rate Sizing: Minimum flow velocities of 1.0 m/s are recommended to maintain turbulent flow conditions and prevent localized cold spots within the coil.
- Insulation Integration: The coil tube trough system should be integrated with thermal insulation (mineral wool or PIR foam, ≥50mm thickness) to minimize heat losses to ambient and direct thermal energy to the ice-melting interface.
- Monitoring: Installation of temperature sensors at 1/4, 1/2, and 3/4 trough length positions is recommended for real-time performance monitoring and control system calibration.
For detailed technical inquiries, custom configuration requests, or sample evaluations, please contact Wenzhou Jixing Metal Materials Co., Ltd. technical sales department.