Stainless Steel Coil Tube for External Ice-Melting Trough Systems
Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered tubular product specifically designed for integration into external ice-melting trough systems. This coil tube serves as the primary heat-transfer conduit in de-icing and anti-icing applications, where controlled thermal distribution is critical to achieving uniform melting across the trough surface. The product is engineered to withstand cyclic thermal loading, mechanical stress from ice accumulation, and prolonged exposure to corrosive winter environmental conditions including road salts, de-icing chemicals, and freeze-thaw cycles.
Drawing upon extensive experimental research into the temperature distribution characteristics of coil-tube-based external ice-melting troughs, this product line embodies the culmination of metallurgical optimization and thermal-hydraulic design principles. The coil tube geometry ensures efficient heat dissipation through extended surface area while maintaining structural integrity under dynamic operational loads.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, predominantly utilizing the following alloy grades:
- SAE 304 / ASTM A312 TP304 — Chromium-Nickel austenitic stainless steel offering excellent general corrosion resistance and weldability, suitable for standard de-icing environments.
- SAE 316 / ASTM A312 TP316 — Molybdenum-enhanced austenitic stainless steel providing superior resistance to chloride-induced pitting and crevice corrosion, recommended for coastal or heavily salted roadway applications.
- SAE 321 / ASTM A312 TP321 — Titanium-stabilized austenitic stainless steel offering enhanced resistance to intergranular corrosion at elevated operating temperatures.
Key Mechanical and Thermal Properties
- Tensile Strength (UTS): ≥ 515 MPa (304); ≥ 515 MPa (316)
- Yield Strength (0.2% Proof Stress): ≥ 205 MPa
- Elongation: ≥ 40% (minimum)
- Thermal Conductivity: 16.3 W/(m·K) at 100°C (304 grade)
- Linear Thermal Expansion Coefficient: 17.3 × 10⁻⁶ /°C (10–100°C)
- Operating Temperature Range: −196°C to +870°C
- Corrosion Resistance: Excellent resistance to atmospheric, aqueous, and chemical corrosion including sodium chloride solutions up to 5% concentration
- Cryogenic Performance: Maintains ductility and toughness at sub-zero temperatures without brittle fracture susceptibility
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Manufacturer | Wenzhou Jixing Metal Materials Co., Ltd. |
| Catalogue No. | 1232 |
| Material Grade | SAE 304 / 316 / 321 (per customer specification) |
| Standard Compliance | ASTM A312 / A269; GB/T 12771; EN 10216-5 |
| Outer Diameter (OD) | 6.0 mm – 32.0 mm (customizable) |
| Wall Thickness | 0.5 mm – 2.0 mm (customizable) |
| Coil Diameter | 300 mm – 1200 mm |
| Coil Length | 15 m – 120 m per coil |
| Surface Finish | Mirror polished (Ra ≤ 0.4 μm) / Brushed / Passivated |
| End Condition | Plain cut / Beveled / Flanged (on request) |
| Tolerance (OD) | ±0.05 mm (precision grade); ±0.10 mm (standard grade) |
| Tolerance (Wall) | ±10% of nominal |
| Forming Method | Cold-rolled & cold-drawn seamless |
| Heat Treatment | Solution annealed (1050–1150°C) + Water quench |
| Passivation | ASTM A967 / A380 compliant |
| Testing | Hydrostatic (2× working pressure); Eddy current; PMI |
| Packaging | Wooden crate / Steel drum with desiccant |
| Minimum Order Quantity | 500 kg per grade |
Manufacturing Process
The production of this stainless steel coil tube follows a rigorous, multi-stage manufacturing protocol designed to ensure dimensional accuracy, metallurgical homogeneity, and surface integrity:
- Raw Material Selection: Only certified vacuum-induction melted (VIM) or argon-oxygen decarburization (AOD) stainless steel billets or slabs are accepted. Each heat is verified through Positive Material Identification (PMI) via optical emission spectrometry (OES) and confirmed against the mill test certificate (MTC).
- Hot Rolling & Annealing: Billets are hot-rolled into seamless tube blanks, followed by solution annealing at 1050–1150°C with rapid water quenching to achieve a fully austenitic microstructure free of carbide precipitation.
- Cold Reduction (Cold Rolling / Cold Drawing): The tube blanks undergo multiple passes of cold reduction to achieve target outer diameter and wall thickness. This process imparts beneficial work hardening while refining grain structure for enhanced mechanical properties.
- Intermediate Annealing: At prescribed reduction intervals, tubes are re-annealed to prevent excessive strain hardening and maintain ductility for subsequent forming operations.
- Coil Forming: The precision-drawn tubes are coiled onto designated coil diameters using automated coiling equipment with controlled tension to prevent ovality or distortion.
- Surface Treatment: Tubes undergo pickling and passivation per ASTM A967 to remove scale, oxide films, and iron contamination, establishing a protective chromium oxide layer. Mirror polishing is achieved through multi-stage buffing and electropolishing where specified.
- Non-Destructive Testing (NDT): Every coil undergoes 100% eddy current inspection for wall thickness uniformity and surface defect detection. Hydrostatic testing is performed at twice the maximum working pressure for a minimum dwell time of 10 seconds.
- Final Inspection & Certification: Each coil is subjected to dimensional verification, visual inspection, and chemical composition confirmation. Full EN 10204 Type 3.1 mill test certificates are issued with each shipment.
Applications
The stainless steel coil tube is purpose-engineered for the following application domains:
- External Ice-Melting Trough Systems: Primary application in airport runway, helipad, and industrial platform de-icing troughs where the coil tube circulates heated fluid (water, glycol-water mixture, or thermal oil) to maintain surface temperatures above freezing. Experimental research on temperature distribution in such systems has demonstrated that coil-tube configurations achieve superior thermal uniformity compared to straight-pipe arrangements.
- Rooftop and Balcony De-Icing: Integration into building envelope heating systems to prevent ice dam formation and ice accumulation on elevated structures.
- Industrial Anti-Icing: Deployment in cold-storage facility loading docks, outdoor conveyor systems, and process equipment in sub-zero environments.
- Marine and Offshore De-Icing: Application on naval vessels and offshore platforms where chloride-rich ice and snow accumulation must be managed without compromising structural integrity.
- Food Processing Equipment: Utilization in hygienic heat-transfer applications where stainless steel's sanitary properties are mandated.
- Automotive Test Facilities: Integration into environmental simulation chambers and cold-weather testing platforms requiring precise thermal control.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management and product certification frameworks:
- ISO 9001:2015 — Quality Management System certification covering all manufacturing processes from raw material procurement through final dispatch.
- ISO 14001:2015 — Environmental Management System certification ensuring environmentally responsible manufacturing practices.
- EN 10204 Type 3.1 — Inspection Certificate confirming that test results are derived from independent third-party inspection of actual product.
- CE Marking — Compliance with European Economic Area health, safety, and environmental protection standards.
- ASTM A312 / A269 Compliance — Conformance to American Society for Testing and Materials specifications for austenitic stainless steel welded and seamless tubes.
- GB/T 12771 — Compliance with Chinese national standard for welded stainless steel tubes for general use.
- EN 10216-5 — Compliance with European standard for seamless and welded austenitic stainless steel tubes for mechanical and technical applications.
- Third-Party Testing — Products are available for independent verification by SGS, BV (Bureau Veritas), or TÜV upon customer request.
Unique Selling Points
The following differentiators distinguish this product from competing offerings in the market:
- Research-Validated Thermal Performance: Product design is informed by peer-reviewed experimental studies on temperature distribution in coil-tube ice-melting trough systems, ensuring optimized thermal uniformity across the trough surface with minimal cold spots or thermal gradients.
- Precision Dimensional Control: Tight tolerances (±0.05 mm on OD for precision grade) ensure reliable integration into pre-engineered trough assemblies without the need for on-site modification.
- Superior Cryogenic Toughness: Full austenitic microstructure eliminates the risk of ductile-to-brittle transition, ensuring reliable performance at temperatures as low as −196°C — critical for Arctic and polar applications.
- Extended Service Life: Solution-annealed and passivated surface provides corrosion resistance exceeding 25 years in typical de-icing environments, significantly outperforming carbon steel alternatives.
- Customizable Coil Configuration: Flexible range of coil diameters (300–1200 mm) and lengths accommodates diverse trough geometries and installation constraints.
- Comprehensive Traceability: Full heat-to-heat traceability from raw material mill certificate through final product inspection ensures complete supply chain accountability.
- Hygienic Surface Finish: Mirror-polished finish (Ra ≤ 0.4 μm) eliminates crevice corrosion initiation sites and facilitates inspection for early-stage defect detection.
Technical Note on Thermal Distribution Performance
Experimental investigations into coil-tube-based external ice-melting trough systems have demonstrated that the helical geometry of the coil tube promotes superior convective heat transfer coefficients compared to straight-pipe configurations. The continuous curvature induces secondary flow patterns within the working fluid, enhancing turbulent mixing and reducing thermal stratification. This results in a more uniform surface temperature profile across the trough width, minimizing localized ice accumulation and reducing overall energy consumption by an estimated 15–25% relative to conventional straight-pipe heating systems of equivalent surface area.
Ordering Information
Customers are advised to specify the following parameters when placing orders:
- Material grade (304, 316, 321, or custom)
- Outer diameter and wall thickness (nominal and tolerance class)
- Coil diameter and preferred coil length
- Surface finish requirement (polished, brushed, passivated, or bare)
- End condition (plain, beveled, or flanged)
- Required certifications and testing protocols
- Special environmental or performance requirements
For detailed quotations, technical consultation, and sample availability, contact Wenzhou Jixing Metal Materials Co., Ltd. directly. Engineering support is available for system-level design optimization of ice-melting trough installations incorporating this coil tube product.