Stainless Steel Coil Tube — Fan Coil Unit Application Grade
Product Overview
The Stainless Steel Coil Tube (产品编号: 1684) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered coiled tubular product specifically designed for integration into large-capacity fan coil units (FCUs) and hydronic HVAC (Heating, Ventilation, and Air Conditioning) systems. These coil tubes serve as the primary heat exchange medium, facilitating efficient thermal transfer between circulating coolant (water or refrigerant) and ambient air drawn through the fan assembly.
As a specialized product within the Documentary Learning (文献学习) category, this coil tube has been rigorously evaluated and characterized through extensive field studies referenced in industry publications such as "Selection and Application of Large Fan Coil Units" (《大风机盘管的选择与应用》). The product represents a mature, application-validated solution for commercial and industrial climate control infrastructure.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, selected for its superior corrosion resistance, thermal conductivity, and long-term structural integrity under cyclic thermal loading conditions.
- Base Material: Austenitic Stainless Steel (奥氏体不锈钢), conforming to ASTM A269 / EN 10216-5 specifications
- Typical Grade: SUS304 (18-8 Chromium-Nickel) or SUS316L (with Molybdenum for enhanced chloride resistance)
- Surface Finish: Mill finish or electropolished (Ra ≤ 0.4 μm for hygienic applications)
- Thermal Conductivity: 14–16 W/(m·K) at 20°C
- Operating Temperature Range: −40°C to +250°C (continuous service)
- Corrosion Resistance: Excellent resistance to atmospheric, aqueous, and mildly acidic environments
- Mechanical Strength: Minimum tensile strength ≥ 520 MPa (SUS304); ≥ 485 MPa (SUS316L)
Specifications
| Parameter | Specification | Unit |
|---|---|---|
| Outer Diameter (OD) | Φ9.52 / Φ12.7 / Φ15.88 / Φ19.05 | mm |
| Wall Thickness | 0.50 / 0.65 / 0.80 / 1.00 | mm |
| Coil Diameter (CD) | 50 – 300 | mm |
| Tube Length (per coil) | 6 – 30 | m |
| Fin Pitch (if finned) | 1.5 – 2.5 | mm |
| Row Configuration | 2 / 3 / 4 rows | — |
| Pressure Rating | ≤ 1.6 (standard) / ≤ 2.5 (reinforced) | MPa |
| Heat Transfer Coefficient | ≥ 800 (air side) / ≥ 3000 (water side) | W/(m²·K) |
| Connection Type | Flared / Threaded / Welded / Brazed | — |
| Maximum Airflow Velocity | ≤ 2.5 | m/s |
Manufacturing Process
The production of these stainless steel coil tubes follows a rigorous multi-stage manufacturing sequence to ensure dimensional accuracy, surface integrity, and mechanical reliability:
- Coil Unwinding & Straightening: Raw stainless steel tube stock is unwound from master coils and cold-straightened to eliminate residual curvature.
- Precision Bending: CNC-controlled mandrel bending machines form the tube into the required serpentine or helical coil geometry with consistent bend radii (typically ≥ 3× OD to prevent wall thinning).
- Hydroforming / Fin Integration: Where applicable, aluminum fins are mechanically integrated onto the coil tube surface to maximize heat exchange surface area.
- Welding & Brazing: Header connections are fabricated using TIG (Tungsten Inert Gas) welding or silver brazing to ensure leak-tight integrity.
- Pressure Testing: Each coil assembly undergoes 100% pneumatic or hydraulic pressure testing at 1.5× the design pressure to verify structural soundness.
- Surface Treatment: Final cleaning, passivation (HNO₃ or citric acid treatment), and optional electropolishing to enhance corrosion resistance.
- Quality Inspection: Dimensional verification via CMM (Coordinate Measuring Machine), visual inspection, and magnetic particle testing (MT) for subsurface defect detection.
Applications
The stainless steel coil tube is a critical component in a wide range of thermal management systems, particularly where large fan coil units are deployed:
- Commercial HVAC Systems: Large-capacity fan coil units in office buildings, shopping malls, hospitals, and educational facilities
- Industrial Process Cooling: Heat rejection in manufacturing environments requiring precise temperature control
- Pharmaceutical & Food Processing: Cleanroom HVAC systems where corrosion resistance and hygienic surface finish are mandatory
- Marine & Coastal Applications: HVAC systems in marine environments where chloride-induced corrosion is a primary concern (SUS316L grade recommended)
- Commercial Refrigeration: Evaporator coils in walk-in coolers, freezers, and display refrigeration units
- District Heating Systems: Terminal heat exchange units in centralized heating networks
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality assurance systems to ensure product conformity with international standards:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System
- ASTM A269 / A270 — Standard specification for seamless and welded austenitic stainless steel tubing
- EN 10216-5 — European standard for non-ferrous metal tubes and pipes
- JIS G3445 — Japanese Industrial Standard for seamless stainless steel tubes
- GB/T 12771 — Chinese National Standard for stainless steel seamless tubes
- ASME B31.9 — Pressure Piping, Refrigeration Piping and Heat Transfer Components
- Third-Party Testing: Material certification per EN 10204 3.1, with optional 3.2 certification for critical applications
Unique Selling Points
- Application-Validated Design: Product specifications derived from documented field performance data in large fan coil unit installations
- Corrosion-Resistant Longevity: Stainless steel construction ensures service life exceeding 25 years in aggressive environments, eliminating copper tube replacement cycles
- Customizable Geometry: Flexible coil configurations (diameter, pitch, row count) tailored to specific FCU design requirements
- Leak-Proof Integrity: 100% pressure-tested assemblies with welded or brazed connections superior to mechanical crimp joints
- Environmental Compliance: Lead-free, recyclable stainless steel construction supporting sustainable building design and LEED certification goals
Note: All specifications are subject to confirmation based on specific project requirements. Wenzhou Jixing Metal Materials Co., Ltd. offers custom engineering solutions and technical consultation for specialized fan coil unit coil tube applications. Contact the engineering department for detailed dimensional drawings, material test reports, and performance data sheets.