Stainless Steel Coil Tube — HVAC Fan Coil Unit Heat Exchanger Tube
Product Overview
The Stainless Steel Coil Tube (Catalog No. 343) manufactured by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered seamless coil tube specifically designed for use in Fan Coil Units (FCUs) and other HVAC (Heating, Ventilation, and Air Conditioning) heat exchange applications. This product represents a critical component in modern building climate control systems, where thermal efficiency, corrosion resistance, and long-term reliability are paramount.
Derived from extensive research into Fan Coil Unit Energy Efficiency Coefficients (EER), this coil tube is engineered to maximize heat transfer performance while minimizing pressure drop across the coil, thereby contributing directly to improved system COP (Coefficient of Performance) and overall energy efficiency in commercial and residential HVAC installations.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, selected for its superior combination of mechanical strength, thermal conductivity, and resistance to oxidation and corrosion under aggressive environmental conditions.
- Base Material: Austenitic Stainless Steel (SAE 304 / SAE 316 / SAE 321)
- Corrosion Resistance: Excellent resistance to atmospheric, aqueous, and chemical corrosion; particularly suited for humid and saline environments
- Thermal Conductivity: Optimized for efficient heat exchange between circulating fluid and ambient air
- Mechanical Strength: Maintains structural integrity under cyclic thermal loading and pressure differentials
- Surface Finish: Electro-polished or mechanically finished interior surface to minimize fouling and reduce hydraulic resistance
- Operating Temperature Range: −40 °C to +250 °C (−40 °F to +482 °F)
- Maximum Working Pressure: Up to 1.6 MPa (232 psi), depending on tube diameter and wall thickness
Technical Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Product Catalog No. | 343 | Internal Classification |
| Product Type | Seamless Coil Tube (盘管) | — |
| Material Grade | SAE 304 / SAE 316 / SAE 321 | ASTM A213 / ASTM A269 |
| Outer Diameter (OD) | 6.0 mm – 12.7 mm (1/4" – 1/2") | ASTM A213 Table 1 |
| Wall Thickness | 0.5 mm – 1.2 mm | ISO 3505 |
| Coil Diameter | 150 mm – 500 mm (configurable) | Custom per application |
| Tube Length per Coil | 3 m – 20 m (continuous) | — |
| Surface Treatment | Electro-polished / Passivated | ASTM A967 |
| Joining Method | Orbitron TIG (Tungsten Inert Gas) welding | ASME B31.9 |
| Hydrostatic Test Pressure | 1.5× working pressure (minimum) | EN 10216-5 |
| Applicable Standards | ASTM, ASME, EN, ISO, GB | Multi-standard compliance |
| Application Category | HVAC Heat Exchanger / Fan Coil Unit | — |
Manufacturing Process
The production of this coil tube follows a rigorous multi-stage manufacturing protocol designed to ensure dimensional accuracy, metallurgical homogeneity, and consistent mechanical performance:
- Hot Rolling & Annealing: Stainless steel ingots are hot-rolled into seamless tube blanks and subsequently annealed to achieve the desired austenitic microstructure and relieve residual stresses.
- Cold Drawing: The tube blanks undergo precision cold drawing through calibrated dies to achieve exact outer diameter and wall thickness tolerances (±0.05 mm), enhancing surface finish and mechanical properties.
- Coiling: The drawn tube is wound into precise coil configurations using CNC-controlled coiling equipment, ensuring uniform curvature radius and minimal mechanical deformation.
- Surface Finishing: Interior and exterior surfaces are electro-polished or mechanically buffed to achieve a Ra (Surface Roughness Average) of ≤0.4 μm, critical for minimizing flow resistance and fouling.
- Passivation & Cleaning: The tube undergoes chemical passivation to remove surface contaminants and establish a stable chromium oxide protective layer (ASTM A967).
- Quality Inspection: Each coil undergoes non-destructive testing (NDT) including eddy current inspection (ECT) for wall thickness uniformity and surface defect detection, followed by hydrostatic pressure testing.
- Packaging & Dispatch: Certified coils are wrapped in protective film, secured on wooden pallets, and labeled with material traceability documentation prior to shipment.
Applications
This coil tube is engineered for a broad spectrum of thermal management applications, with particular emphasis on HVAC systems where energy efficiency is a governing design parameter:
- Fan Coil Units (FCUs): Primary heat exchange element in commercial and residential fan coil systems for space heating and cooling
- Chilled Water / Hot Water Coils: Integrated into air handling units (AHUs) and rooftop units (RTUs)
- Condenser & Evaporator Coils: Used in refrigeration and air conditioning systems
- Heat Recovery Systems: Deployed in energy recovery ventilators (ERVs) and heat exchangers
- Industrial Process Cooling: Applicable in food processing, pharmaceutical, and chemical manufacturing heat exchangers
- Marine HVAC Systems: Suitable for saltwater and high-humidity environments due to 316-grade corrosion resistance
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management framework ensuring full compliance with international and national standards:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001:2015 — Environmental Management System certification
- CE Marking — Conformity with European directives for safety and performance
- ASTM A213 / A269 Compliance — Seamless austenitic stainless steel tube standards
- EN 10216-5 — European standard for heat exchanger and boiler tubes
- GB/T 14976 — Chinese national standard for seamless stainless steel tubes
- ASME B31.9 — Pressure piping for refrigeration and air-conditioning
Unique Selling Points
Energetically Optimized Design: Informed by research into Fan Coil Unit Energy Efficiency Coefficients, this coil tube geometry is designed to maximize surface-area-to-volume ratio while minimizing flow resistance, directly contributing to improved EER and system COP.
- Enhanced Heat Transfer Performance: Precision-drawn interior surfaces and optimized coil geometry reduce thermal boundary layer resistance, increasing heat exchange efficiency by up to 15% compared to conventional coil tubes.
- Superior Corrosion Durability: Available in SAE 316 grade with molybdenum addition for exceptional resistance to chloride-induced pitting and crevice corrosion, extending service life in aggressive environments.
- Full Traceability: Each coil is accompanied by a Mill Test Certificate (MTC) and heat-number traceability documentation ensuring complete material provenance.
- Customizable Configurations: Flexible manufacturing capability allows customization of coil diameter, tube length, OD, wall thickness, and surface finish to meet specific OEM requirements.
- Reduced Lifecycle Cost: The combination of corrosion resistance, low fouling tendency, and high thermal efficiency results in lower maintenance frequency and energy consumption over the product lifecycle.
Wenzhou Jixing Metal Materials Co., Ltd — A trusted manufacturer of precision stainless steel tubing and coil products, committed to delivering engineering excellence, regulatory compliance, and value-driven solutions for the global HVAC and industrial heat exchange markets.