Stainless Steel Coil Tube (Coiltube) — Wenzhou Jixing Metal Materials Co., Ltd.
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered tubular product designed for demanding thermal management and fluid transport applications. This product is supplied in continuous coil form, enabling efficient downstream processing, cutting, and forming without the need for additional welding or joint fabrication. The coil configuration offers superior material utilization, reduced waste, and enhanced logistics efficiency compared to straight-length pipe products.
Based on extensive experimental research into direct evaporative coil tube external ice storage mechanisms, this product line has been optimized for high-performance thermal exchange applications, including ice storage air conditioning systems, heat recovery units, and advanced refrigeration circuits. The coil tube's geometry and material properties are specifically tailored to maximize heat transfer efficiency while maintaining structural integrity under cyclic thermal loading conditions.
2. Material & Properties
The Coil Tube is fabricated from high-grade austenitic stainless steel, primarily conforming to the following alloy designations:
- AISI 304 (UNS S30400): The standard grade offering excellent general corrosion resistance, good formability, and wide temperature range suitability.
- AISI 316 (UNS S31600): Enhanced corrosion resistance due to molybdenum addition (2–3% Mo), suitable for aggressive chemical and marine environments.
- AISI 316L (UNS S31603): Low-carbon variant of 316L providing superior weldability and resistance to intergranular corrosion.
- AISI 321 (UNS S32100): Titanium-stabilized grade offering enhanced resistance to intergranular corrosion at elevated temperatures (450–850°C).
- AISI 310S (UNS S31008): High-temperature grade with exceptional oxidation resistance up to 1150°C.
Key mechanical and physical properties include:
- Tensile Strength (UTS): 515–720 MPa (grade dependent)
- Yield Strength (0.2% Proof Stress): 205–310 MPa
- Elongation at Break: ≥ 35% (minimum)
- Operating Temperature Range: −196°C to +870°C (304/316 grades)
- Thermal Conductivity: 14.9–16.3 W/(m·K) at 20°C
- Specific Heat Capacity: ~500 J/(kg·K)
- Corrosion Resistance: Excellent resistance to atmospheric, aqueous, and chemical corrosion; pitting resistance number (PREN) ≥ 19 for 316L
3. Specifications
| Parameter | Specification / Range |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Manufacturer | Wenzhou Jixing Metal Materials Co., Ltd. |
| Catalog Reference No. | 1375 |
| Outer Diameter (OD) | Φ3.0 mm – Φ50.8 mm (custom sizes available) |
| Wall Thickness | 0.3 mm – 3.0 mm (tolerance ±0.05 mm) |
| Coil Inner Diameter (ID) | Φ100 mm – Φ600 mm |
| Coil Length per Spool | 100 m – 500 m (standard); up to 1000 m (special order) |
| Surface Finish | No. 1, 2B, BA (Bright Annealed), Electropolished (Ra ≤ 0.4 μm) |
| Manufacturing Standard | ASTM A213/A213M, ASTM A269/A269M, GB/T 12771, EN 10216-5 |
| Available Grades | 304, 304L, 316, 316L, 321, 310S, 2205 (Duplex) |
| End Condition | Plain cut, sealed ends, or customized |
| Packaging | Wooden crate / steel drum with moisture-proof wrapping |
4. Manufacturing Process
The production of Wenzhou Jixing's Stainless Steel Coil Tube follows a rigorous, multi-stage manufacturing process to ensure dimensional accuracy, metallurgical quality, and surface integrity:
- Material Selection & Incoming Inspection: Raw stainless steel strip or seamless tube blanks are procured from certified mills. Each batch undergoes spectrographic analysis (PMI — Positive Material Identification) to verify chemical composition compliance.
- Slitting & Cutting: Wide-strip material is precision-slitted to the target coil tube blank width using high-speed slitting lines with laser-guided edge tracking.
- Forming & Welding (Welded Coil Tube): The slit strip is formed into a helical coil using precision roll-forming equipment. A continuous TIG (Tungsten Inert Gas) welding process is applied under argon shielding to produce a fusion-welded coil tube with a smooth, clean weld seam.
- Alternative — Seamless Coil Tube: For critical applications, seamless coil tubes are produced via cold-drawing or cold-rolling of seamless tube blanks, eliminating the weld seam entirely.
- Heat Treatment & Annealing: Continuous annealing in a protective atmosphere (nitrogen or hydrogen) restores the austenitic microstructure, relieves residual stresses, and achieves the desired mechanical properties.
- Pickling & Passivation: The tube surface is treated with a mixed acid solution (nitric + hydrofluoric acid) to remove scale and oxide layers, followed by passivation to establish a protective chromium oxide film.
- Precision Coiling & Winding: The finished tube is wound onto a precision coil former at controlled tension to achieve the specified coil inner diameter with uniform layer-to-layer spacing.
- Quality Inspection: Every coil undergoes hydrostatic testing (pressure test at 1.5× working pressure), dimensional measurement, surface inspection, and (where applicable) radiographic testing (RT) of weld seams.
- Packaging & Dispatch: Coils are wrapped in VCI (Vapor Corrosion Inhibitor) film, secured on wooden or steel spools, and labeled with full traceability documentation.
5. Applications
The Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd. serves a diverse range of industrial and commercial applications:
- Ice Storage Air Conditioning Systems: As demonstrated in experimental research on direct evaporative coil tube external ice storage mechanisms, these coil tubes function as the primary heat exchange element in thermal energy storage (TES) systems, enabling efficient off-peak cooling and peak-load shifting.
- Refrigeration & HVAC: Evaporator and condenser coils for commercial refrigeration units, chillers, heat pumps, and air-handling units.
- Food & Beverage Processing: Heat exchangers, pasteurization circuits, and sanitary piping systems requiring high corrosion resistance and cleanability.
- Pharmaceutical & Biotechnology: CIP (Clean-In-Place) systems, bioreactor heat exchange coils, and process piping in GMP-regulated environments.
- Chemical Processing: Reactor coil jackets, distillation column internals, and corrosive fluid transfer lines.
- Automotive & Aerospace: Fuel lines, hydraulic circuits, and thermal management systems requiring lightweight, corrosion-resistant tubing.
- Heat Recovery & Waste Heat Utilization: Economizers, air preheaters, and thermal recovery units in industrial processes.
- Marine & Offshore: Seawater heat exchanger coils and ballast water system components benefiting from 316L's superior chloride resistance.
6. Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework ensuring full traceability and international compliance:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- EN 10204 Type 3.1 — Inspection Certificate (Mill Test Certificate with independent inspection)
- CE Marking — Conformity with European standards for pressure equipment and construction products
- ASME — American Society of Mechanical Engineers certification for pressure-containing applications
- GB/T Standards Compliance — Full conformity with Chinese national standards for stainless steel pipe and tube products
Each production batch is accompanied by a Mill Test Certificate (MTC) documenting chemical composition (via optical emission spectrometry), mechanical test results, heat treatment records, and dimensional verification data. Third-party inspection by agencies such as SGS, Bureau Veritas, or TÜV is available upon request.
7. Unique Selling Points
The integration of experimental research findings on direct evaporative coil tube ice storage mechanisms into product design gives Wenzhou Jixing's Coil Tube a distinctive advantage in thermal energy storage applications. The optimized coil geometry, combined with high-purity austenitic stainless steel, delivers superior heat transfer coefficients and long-cycle durability under repeated freeze-thaw conditions.
- Research-Backed Design: Product specifications informed by peer-reviewed experimental research on ice storage thermal dynamics, ensuring proven performance in TES systems.
- Continuous Coil Configuration: Eliminates field welding, reduces leak risk, and minimizes installation labor and cost.
- Customizability: Wide range of diameters, wall thicknesses, surface finishes, and grades to meet specific engineering requirements.
- Full Traceability: Every coil is traceable to its mill heat number through complete digital documentation.
- Cost Efficiency: Coil form factor maximizes material utilization (up to 98% yield rate) and reduces logistics costs per meter of finished tube.