Stainless Steel Coil Tube for Fan Coil Unit Heat Exchangers
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 use in fan coil unit (FCU) air conditioning systems, heat exchangers, and thermal management applications. These coil tubes serve as critical heat transfer elements within dynamic HVAC (Heating, Ventilation, and Air Conditioning) control systems, where reliable thermal performance, corrosion resistance, and mechanical integrity are paramount.
Modern fan coil unit systems require coil tubes that can withstand continuous thermal cycling, fluid dynamic stresses, and varying environmental conditions. Wenzhou Jixing Metal Materials Co., Ltd. addresses these demanding requirements through advanced metallurgical processing and rigorous quality control, delivering coil tubes that meet international standards for industrial and commercial applications.
Material & Properties
The coil tube products are fabricated from high-grade austenitic stainless steel grades, including but not limited to AISI 304 (UNS S30400), AISI 316L (UNS S31603), and AISI 321 (UNS S32100), selected based on the specific thermal and chemical requirements of the end application.
- Corrosion Resistance: Superior resistance to pitting, crevice corrosion, and stress corrosion cracking, particularly in humid and chemically aggressive environments typical of HVAC systems.
- Thermal Conductivity: Optimized thermal transfer characteristics ensuring efficient heat exchange between the refrigerant/circulating fluid and the surrounding air stream in FCU applications.
- Mechanical Strength: High tensile and yield strength at both ambient and elevated operating temperatures, providing structural integrity under pressure differentials.
- Weldability: Excellent welding properties enabling reliable fabrication of fin-tube heat exchanger assemblies without compromising material integrity.
- Hygienic Surface Quality: Smooth interior and exterior surfaces minimizing fouling and biofilm accumulation, critical for air handling applications.
Specifications
| Parameter | Specification |
|---|---|
| Material Grades | AISI 304, 316L, 321, 310S (upon request) |
| Outer Diameter (OD) | 6.35 mm – 25.4 mm (¼" – 1") |
| Wall Thickness | 0.5 mm – 2.0 mm |
| Coil Diameter | 100 mm – 500 mm (configurable) |
| Tube Length (per coil) | Up to 200 m continuous coil |
| Surface Finish | Ba & E (Bright Annealed & Pickled), No. 4 Brushed |
| Maximum Operating Temperature | -60°C to +600°C (grade dependent) |
| Maximum Operating Pressure | Up to 1.6 MPa (16 bar) |
| Tolerance (OD) | ±0.05 mm |
| Tolerance (Wall Thickness) | ±10% of nominal |
| Standards Compliance | ASTM A269, ASTM A270, GB/T 12771, EN 10217 |
| Deliverable Form | Coiled (Coiltube), Cut Length, Formed Coil |
Manufacturing Process
The production of Wenzhou Jixing Metal Materials Co., Ltd. stainless steel coil tubes follows a multi-stage precision manufacturing process:
- Raw Material Selection: Sourcing of certified stainless steel strip or seamless tube stock from approved suppliers, with full chemical composition verification via spectroscopic analysis.
- Coil Winding & Forming: Precision coil winding on calibrated mandrels to achieve specified coil diameters with uniform curvature, preventing stress concentrations and residual deformation.
- Heat Treatment: Solution annealing at 1050°C – 1150°C followed by controlled cooling to restore full austenitic structure, eliminate residual stresses, and optimize corrosion resistance.
- Pickling & Passivation: Acid pickling to remove oxide scale, followed by passivation treatment to establish a protective chromium oxide film on the tube surface.
- Dimensional Inspection: In-line and end-of-line dimensional verification including outer diameter, wall thickness, straightness, and coil geometry using laser measurement and CMM (Coordinate Measurement Machine) systems.
- Pressure Testing: Hydrostatic or pneumatic pressure testing at 1.5× maximum operating pressure to verify leak-tightness and structural integrity.
- Packaging & Dispatch: Protective wrapping, moisture-barrier packaging, and labeling with full traceability documentation.
Applications
Primary Application: Fan Coil Unit (FCU) Air Conditioning Systems
Stainless steel coil tubes are integral components of fan coil unit heat exchangers used in commercial buildings, hospitals, laboratories, and industrial facilities. In these systems, the coil tubes facilitate heat exchange between a circulating refrigerant or hot water medium and the air stream driven by the fan, enabling precise temperature and humidity control.
Recent advances in dynamic control process simulation platforms—such as Modelica-based FCU system modeling—have demonstrated the critical importance of coil tube thermal performance characteristics in achieving optimal system dynamics. Accurate modeling of the heat transfer coefficients, fluid residence time, and thermal inertia of the coil tube assembly is essential for developing robust control algorithms that minimize energy consumption while maintaining occupant comfort.
Additional Applications
- Chiller and condenser heat exchanger assemblies
- Process cooling systems in food and pharmaceutical industries
- Automotive and marine HVAC systems
- Industrial heat recovery systems
- Water heating and solar thermal collector assemblies
- Cryogenic and low-temperature fluid transport systems
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework ensuring consistent product performance:
- ISO 9001:2015 – Quality Management System certification for consistent manufacturing processes
- ISO 14001:2015 – Environmental Management System certification for sustainable production practices
- CE Marking – Conformity with European health, safety, and environmental protection standards
- EN 10204 3.1 – Third-party inspection certificates for material compliance
- Mill Test Reports (MTR) – Full traceability documentation including chemical analysis, mechanical test results, and heat treatment records for every production lot
- NDT (Non-Destructive Testing) – Eddy current testing and hydrostatic testing for defect detection and pressure integrity verification
Unique Selling Points
Engineered for Dynamic HVAC Systems: Our coil tubes are specifically optimized for the thermal cycling and dynamic load conditions encountered in modern fan coil unit systems with advanced control algorithms, ensuring consistent performance throughout the equipment lifecycle.
- Precision Dimensional Control: Tight manufacturing tolerances ensure optimal fit within fin-tube heat exchanger assemblies, minimizing air bypass and maximizing heat transfer efficiency.
- Full Traceability: Every coil tube lot is accompanied by comprehensive documentation enabling complete supply chain traceability from raw material to finished product.
- Custom Configuration Capability: Flexible manufacturing capacity allows customization of coil diameter, tube dimensions, and surface treatments to meet specific OEM (Original Equipment Manufacturer) requirements.
- Extended Service Life: Superior corrosion resistance and fatigue performance result in significantly longer service intervals compared to carbon steel alternatives, reducing total cost of ownership.
- Integration with Advanced Control Systems: Product thermal properties are well-characterized and documented, facilitating accurate inclusion in Modelica and other simulation platforms for FCU dynamic control system development and optimization.
Wenzhou Jixing Metal Materials Co., Ltd. is committed to delivering premium stainless steel coil tube solutions that meet the exacting demands of modern HVAC engineering, industrial heat transfer, and thermal management applications worldwide.