Stainless Steel Coil Tube (Fan Coil Unit Application Series)
Product Code: JX-CT-410 | Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd. (温州吉兴金属材料有限公司)
Product Category: Coiled Stainless Steel Tubing for HVAC Heat Exchange Systems
1. Product Overview
The JX-CT-410 Stainless Steel Coil Tube is a precision-engineered coiled tube product specifically designed for integration into Fan Coil Units (FCUs) and similar HVAC (Heating, Ventilation, and Air Conditioning) systems. This product represents a critical component in room thermal coupling applications, where efficient heat transfer between the coil tube and ambient air determines overall system performance.
Based on advanced research in fan coil unit on/off control strategies coupled with room thermal dynamics, this coil tube series has been optimized to achieve superior thermal response characteristics, minimal pressure drop, and extended service life. The coiled geometry provides a high surface-area-to-volume ratio, enabling rapid heat exchange during both heating and cooling cycles.
The product is manufactured by Wenzhou Jixing Metal Materials Co., Ltd., a leading supplier of specialty stainless steel tube products based in Wenzhou, Zhejiang Province, China, with decades of expertise in precision tubing fabrication.
2. Material & Properties
2.1 Base Material
The coil tube is fabricated from high-grade austenitic stainless steel, primarily conforming to the following grades:
- ASTM A213 TP304 / TP316L — General purpose and enhanced corrosion resistance applications
- SUS304 / SUS316L — Japanese Industrial Standard equivalent grades
- 12Cr18Ni9 / 022Cr17Ni12Mo2 — Chinese National Standard (GB/T) designations
2.2 Key Material Properties
- Thermal Conductivity: 16.3 W/(m·K) at 100°C (typical for 304 SS)
- Specific Heat Capacity: 0.50 kJ/(kg·K)
- Corrosion Resistance: Excellent resistance to atmospheric, aqueous, and chemical corrosion
- Operating Temperature Range: −196°C to +870°C
- Mechanical Strength: Tensile strength ≥ 520 MPa; Yield strength ≥ 205 MPa
- Surface Finish: Mirror polish (Ra ≤ 0.4 μm) or industrial finish (Ra ≤ 1.6 μm)
2.3 Performance Advantages
The austenitic stainless steel matrix ensures non-magnetic properties, resistance to intergranular corrosion, and excellent weldability — all critical attributes for coil tubes operating within closed-loop refrigerant or hot water circulation systems. The material's low carbon variant (316L) further eliminates the risk of sensitization during welding operations.
3. Specifications
| Parameter | Specification | Tolerance |
|---|---|---|
| Outer Diameter (OD) | 6.35 mm / 8.00 mm / 9.53 mm / 12.70 mm | ±0.05 mm |
| Wall Thickness (WT) | 0.40 mm / 0.50 mm / 0.60 mm / 0.80 mm | ±0.03 mm |
| Coil Pitch (Turn Spacing) | 10.0 – 25.0 mm (configurable) | ±0.2 mm |
| Coil Diameter | φ100 mm – φ300 mm | ±2 mm |
| Tube Length (per coil) | 1.5 m – 6.0 m | ±10 mm |
| Number of Turns | 50 – 200 turns (standard) | ±2 turns |
| End Form | Flat cut / Beveled / Flared / Threaded | Per drawing |
| Surface Treatment | Pickled & Passivated / Electropolished | — |
| Maximum Working Pressure | 1.6 MPa (standard) / 4.0 MPa (heavy-wall) | Hydro-tested at 1.5× |
| Refrigerant Compatibility | R22, R410A, R32, R134a, R407C, R404A | — |
| Heat Medium | Water / Glycol solution / Refrigerant | — |
| Applicable Standards | ASTM A213, GB/T 14976, EN 10216-5 | — |
| Coating (Optional) | Nickel plating / Passivation film | — |
4. Manufacturing Process
4.1 Process Flow
- Raw Material Selection: Cold-rolled stainless steel strip/coil from certified mills (e.g., Outokumpu, POSCO, Taigang) with full mill test certificates (MTC).
- Coil Forming: Precision CNC-controlled coil winding on high-torque winding machines to ensure uniform pitch and diameter throughout the entire length.
- Welding: TIG (Tungsten Inert Gas) welding for tube-to-tube joints and tube-to-header connections, using matching filler wire (ER308L/ER316L).
- Pickling & Passivation: Immersion in nitric-hydrofluoric acid solution followed by passivation treatment to remove weld discoloration and restore the protective chromium oxide layer.
- Pressure Testing: Hydrostatic pressure test at 1.5× the maximum working pressure to verify integrity and absence of leaks.
- Surface Finishing: Optional electropolishing or mirror polishing to achieve specified surface roughness for enhanced heat transfer efficiency.
- Quality Inspection: Dimensional verification, visual inspection, and spectroscopic composition analysis.
4.2 Quality Control Measures
- 100% visual inspection of all weld joints
- Random sampling for ultrasonic thickness measurement
- Spectrometer verification of chemical composition (PMI testing)
- Batch hydrostatic pressure testing with documented results
- Coil geometry verification using laser measurement systems
5. Applications
5.1 Primary Applications
- Fan Coil Units (FCUs): Core heat exchange element in commercial and residential HVAC systems, providing room-level temperature control through forced air convection.
- Chiller & Condenser Coils: Evaporator and condenser components in central air conditioning systems.
- Industrial Heat Exchangers: Shell-and-tube and plate-fin heat exchanger tubing for process heating and cooling.
- Refrigeration Systems: Evaporator coils in commercial refrigeration equipment and cold storage facilities.
5.2 Secondary Applications
- Automotive heating, ventilation, and air conditioning (HVAC) components
- Building management systems (BMS) thermal control loops
- Food processing and pharmaceutical industry sanitary heat exchangers
- Marine and offshore HVAC systems requiring corrosion-resistant tubing
- Solar thermal collector systems
5.3 Thermal Performance Context
Research on fan coil unit on/off control strategies coupled with room thermal dynamics has demonstrated that coil tube geometry — including pitch, diameter, and tube count — directly influences the system's thermal inertia and response time. Optimized coil configurations enable reduced energy consumption by 15–25% through improved part-load efficiency and minimized short-cycling.
6. Quality Certifications & Standards Compliance
6.1 Certifications
- ISO 9001:2015 — Quality Management System
- ISO 14001:2015 — Environmental Management System
- ISO 45001:2018 — Occupational Health & Safety Management
- CE Marking — Conformity with European directives
- SGS Testing Reports — Third-party material and dimensional verification
- Mill Test Certificates (MTC) — EN 10204 3.1 Type for each batch
6.2 Applicable Standards
- ASTM A213 — Standard Specification for Seamless Austenitic Stainless Steel Tubing for High-temperature Service
- GB/T 14976 — Cold-rolled or cold-drawn seamless stainless steel tubes
- EN 10216-5 — Non-alloy and alloy steel tubes for pressure purposes
- ASME B31.5 — Refrigeration Piping and Heat Transfer Components
- ASHRAE 34 — Standard for Refrigerant Safety Classification
7. Unique Selling Points
- Superior Thermal Response: Optimized coil geometry minimizes thermal lag, enabling rapid temperature stabilization in coupled room environments.
- Extended Service Life: Austenitic stainless steel construction provides 20+ year service life without corrosion-related degradation.
- Precision Manufacturing: CNC-controlled coil forming ensures consistent pitch and diameter, reducing turbulence and pressure drop.
- Customizable Configurations: Wide range of OD, wall thickness, and coil dimensions available to match specific FCU design requirements.
- Full Traceability: Each batch is accompanied by complete documentation including MTC, pressure test records, and dimensional inspection reports.
- Environmental Compliance: RoHS compliant; no lead, cadmium, or mercury in material composition.
- Energy Efficiency Contribution: Reduced pressure drop translates to lower fan power consumption in FCU systems, contributing to overall energy savings.
8. Packaging & Delivery
- Individual coil tubes packed in moisture-proof polyethylene bags
- Stacked on wooden pallets with protective corner guards
- Export-grade packaging for international shipping (ISPM 15 compliant pallets)
- Lead time: 15–25 working days for standard orders; 30–40 days for custom specifications
- Minimum Order Quantity (MOQ): 500 meters per specification
Document Reference: JX-CT-410-TS-2024 | Wenzhou Jixing Metal Materials Co., Ltd. | Technical Specification Rev. 1.0