Stainless Steel Coil Tube (Coiltube) — Product Technical Specification
Product Overview
The Stainless Steel Coil Tube (Coiltube) is a precision-engineered continuous-loop tubing product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Designed primarily for HVAC (Heating, Ventilation, and Air Conditioning) systems and industrial heat exchange applications, this coil tube delivers superior thermal conductivity, corrosion resistance, and mechanical durability. The product is supplied in a coiled configuration to facilitate ease of installation, storage, and transport, making it an ideal solution for applications requiring flexible routing through complex architectural or mechanical layouts.
This product line has been extensively validated through experimental research on Fan Coil Unit (FCU) Dehumidification Performance, demonstrating its effectiveness in moisture control, thermal regulation, and energy-efficient operation within commercial and residential HVAC systems.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, selected for its exceptional balance of mechanical strength, thermal performance, and resistance to environmental degradation.
- Base Material: Austenitic Stainless Steel — conforming to AISI 304, AISI 316, and equivalent grades (UNS S30408, UNS S31603)
- Corrosion Resistance: Excellent resistance to atmospheric corrosion, chemical attack, and pitting, particularly in chloride-containing environments (316 grade)
- Thermal Conductivity: 14.9–16.3 W/(m·K) at 20°C, ensuring efficient heat transfer in heat exchanger and fan coil applications
- Mechanical Strength: Tensile strength of 515–720 MPa; yield strength ≥ 205 MPa
- Temperature Range: Continuous operation from −196°C to +870°C
- Surface Finish: Polished, pickled, or passivated surface with Ra ≤ 0.8 μm for reduced flow resistance and enhanced hygiene
- Hygienic Compliance: Suitable for food-grade and pharmaceutical applications where sanitary conditions are required
Technical Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | Φ6.0 mm — Φ25.4 mm (customizable) | ISO 14612 / GB/T 12771 |
| Wall Thickness | 0.5 mm — 2.0 mm | ASTM A269 / ASTM A312 |
| Coil Diameter (CD) | 300 mm — 1,200 mm | Manufacturer Specification |
| Coil Length | Up to 50 m per coil (continuous) | — |
| Material Grade | AISI 304 / AISI 316 / AISI 321 | ASTM A270 |
| Surface Condition | Pickled & Passivated / Mirror Polished | ASTM A403 |
| Welding Method | Automatic TIG (Tungsten Inert Gas) Orbital Welding | ISO 6846 |
| Maximum Working Pressure | 1.6 MPa (standard); up to 6.3 MPa (custom) | ASME B31.3 |
| Dimensional Tolerance | ±0.1 mm (OD); ±10% (wall thickness) | GB/T 14976 |
| Minimum Bend Radius | 2× OD (without mandrel); 1× OD (with mandrel) | — |
| End Condition | Plain end / Beveled end / Threaded (custom) | — |
| Delivery Condition | Coiled, bundled, and shrink-wrapped | — |
Manufacturing Process
The production of the Stainless Steel Coil Tube follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Selection: Virgin stainless steel strip is procured from certified mills, verified for chemical composition (spectrometric analysis) and mechanical properties.
- Coiling & Forming: The flat strip is fed through precision roll-forming dies that progressively shape the tube to the specified outer diameter and wall thickness. A continuous mandrel system maintains internal roundness and prevents ovality.
- Welding: A seamless-appearing longitudinal weld is formed using high-frequency induction welding (HF) or automatic TIG welding with inert gas shielding (argon) to prevent oxidation and ensure weld integrity.
- Heat Treatment: Solution annealing at 1050°C–1150°C followed by controlled cooling to restore full austenitic microstructure and eliminate residual stresses from forming and welding.
- Pickling & Passivation: The tube is immersed in a nitric-hydrofluoric acid solution to remove oxide scale and iron contamination, followed by a passivation treatment to form a protective chromium oxide film.
- Dimensional Inspection: Each coil undergoes ultrasonic wall thickness measurement, optical OD inspection, and hydrostatic pressure testing (typically at 1.5× working pressure) to verify leak-tightness.
- Coiling & Packaging: The finished tube is wound onto a steel core or coil former, wrapped in protective film, and secured with steel strapping for transport.
Applications
The Stainless Steel Coil Tube finds extensive use across multiple industrial and commercial sectors:
- HVAC & Fan Coil Units (FCU): Serves as the primary heat exchange element in fan coil units, providing efficient dehumidification, heating, and cooling performance. Experimental research has validated its superior moisture control characteristics in air conditioning applications.
- Refrigeration & Cold Storage: Utilized in evaporator and condenser coils for commercial refrigeration systems, cold chain logistics, and industrial freezing applications.
- Automotive Industry: Employed in engine cooling loops, intercooler piping, and HVAC systems within vehicles.
- Food & Beverage Processing: Used in pasteurization systems, brewing equipment, and sanitary fluid transfer lines due to its hygienic surface finish and corrosion resistance.
- Pharmaceutical & Biotechnology: Applied in process piping, heat exchangers, and clean-in-place (CIP) systems requiring high purity standards.
- Chemical Processing: Suitable for conveying aggressive fluids, acids, and alkaline solutions in chemical plants and refineries.
- Building Services & Plumbing: Used in radiant floor heating systems, domestic hot water recirculation loops, and central heating distribution networks.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework ensuring full traceability and compliance with international standards:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- ISO/TS 22163 — Automotive Quality Management System (IATF 16949 equivalent)
- CE Marking — Conformity with European directives for pressure equipment (PED 2014/68/EU)
- ASME Stamp — Certification for pressure-containing components (where applicable)
- EN 10204 3.1 — Third-party material certification and inspection reports provided with every shipment
- Mill Test Certificates (MTC): Full chemical analysis and mechanical property reports for each heat number
- Hydrostatic Testing: 100% pressure testing on all coils prior to dispatch
- Spectrometric Verification: On-site chemical composition verification using portable XRF (X-Ray Fluorescence) analyzers
Unique Selling Points
- Validated Dehumidification Performance: Backed by experimental research on fan coil unit dehumidification, demonstrating measurable improvements in latent heat removal efficiency compared to conventional copper-tube alternatives.
- Superior Corrosion Resistance: Eliminates the risk of tube degradation, scaling, and leakage associated with carbon steel or copper tubing in humid or chemically aggressive environments.
- Lightweight & Flexible: Lower specific weight than copper tubing (0.28–0.81 g/cm³ vs. 8.96 g/cm³), reducing structural support requirements and simplifying installation.
- Continuous Coil Format: Delivered in long, uninterrupted lengths, minimizing field joints and potential leak points while enabling custom cutting to exact project requirements.
- Hygienic & Non-Toxic: Suitable for food, beverage, and pharmaceutical applications without risk of metallic contamination or taste transfer.
- Full Customization: Available in a wide range of diameters, wall thicknesses, coil diameters, and surface finishes to meet project-specific engineering requirements.
- Environmentally Sustainable: Stainless steel is 100% recyclable with no loss of material properties, supporting circular economy and ESG (Environmental, Social, and Governance) objectives.
Conclusion
The Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd. represents a premium-grade solution for HVAC, heat exchange, and industrial fluid handling applications. Combining proven dehumidification performance, exceptional material durability, and rigorous quality assurance, this product delivers reliable long-term service with minimal maintenance requirements. Its versatile coiled configuration and comprehensive compliance with international standards make it a preferred choice for engineers, OEM manufacturers, and project contractors worldwide.