Stainless Steel Coil Tube for Fan Coil Unit Applications
Product Overview
The Stainless Steel Coil Tube (Product No. 1687) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered tubular product specifically designed for use in fan coil unit (FCU) systems and HVAC (Heating, Ventilation, and Air Conditioning) applications. These coil tubes serve as the primary heat exchange elements within fan coil systems, facilitating efficient thermal transfer between the circulating medium (water, refrigerant, or glycol solution) and the ambient air stream. The product is engineered to meet the demanding requirements of modern building climate control systems, ensuring optimal performance in both heating and cooling cycles.
Material & Properties
The coil tubes are fabricated from high-grade austenitic stainless steel, selected for their superior corrosion resistance, mechanical integrity, and thermal conductivity characteristics. The material composition and key physical properties are as follows:
- Base Material: Austenitic Stainless Steel (SAE 304 / SAE 316L grade options available)
- Corrosion Resistance: Excellent resistance to pitting, crevice corrosion, and intergranular corrosion in aqueous environments
- Operating Temperature Range: −196°C to +870°C (−321°F to +1,598°F)
- Thermal Conductivity: 14.9–16.3 W/(m·K) at 20°C
- Non-magnetic: Naturally non-magnetic in annealed condition, ensuring compatibility with sensitive electromagnetic environments
- Hygienic Surface: Low surface roughness (Ra ≤ 0.4 μm) suitable for potable water and sanitary applications
- Weldability: Excellent weldability with minimal distortion, enabling reliable joint integrity in coil assembly
Specifications
| Parameter | Specification | Unit |
|---|---|---|
| Outer Diameter (OD) | 9.52 / 12.70 / 15.88 / 19.05 | mm |
| Wall Thickness | 0.50 – 1.00 | mm |
| Coil Pitch (Center-to-Center) | 6.00 – 12.00 | mm |
| Number of Rows | 2 / 4 / 6 (configurable) | — |
| Coil Length (Tube Length per Pass) | 1,200 – 3,000 | mm |
| Fin Type | Aluminum louvered / plain / corrugated fins | — |
| Fin Density | 10 – 14 | fins/inch |
| Working Pressure | Up to 1.6 MPa (232 psi) | MPa |
| Test Pressure | 2.4 MPa (348 psi) | MPa |
| Tolerance (OD) | ±0.05 | mm |
| Tolerance (Wall Thickness) | ±0.03 | mm |
| Surface Finish | Mirror polished / electropolished / brushed | — |
| End Treatment | Deburred, chamfered, or flared per customer specification | — |
| Packaging | Wooden crate / export-grade container with protective wrapping | — |
Manufacturing Process
The production of these coil tubes follows a rigorous, multi-stage manufacturing process designed to ensure dimensional accuracy, metallurgical soundness, and functional reliability:
- Raw Material Selection & Inspection: Certified stainless steel strip or wire is sourced from approved mills, with full chemical composition analysis and mechanical property verification prior to processing.
- Coil Forming: High-precision CNC (Computer Numerical Control) coiling machinery is employed to form the tube into the specified helical geometry, maintaining consistent pitch and alignment throughout the coil length.
- Welding: Where continuous tube length is required, orbital TIG (Tungsten Inert Gas) welding is utilized to create seamless internal joints with full-penetration weld integrity, minimizing flow turbulence and pressure drop.
- Heat Treatment: Solution annealing is performed at temperatures between 1,010°C and 1,150°C followed by controlled cooling to restore full austenitic microstructure and relieve residual stresses induced during forming.
- Surface Treatment: Electropolishing or mechanical polishing is applied to achieve the required surface roughness, enhancing both aesthetic quality and fluid dynamics performance within the coil channels.
- Fin Application: Aluminum fins are mechanically bonded to the stainless steel coil tube using high-conductivity thermal interface material, ensuring maximum heat transfer area and thermal contact efficiency.
- Quality Inspection: Each unit undergoes dimensional verification (CMM — Coordinate Measuring Machine), pressure testing, visual inspection, and eddy current testing to detect subsurface defects.
Applications
The Stainless Steel Coil Tube is engineered for a broad spectrum of thermal management applications, with particular emphasis on fan coil unit systems. Key application domains include:
- HVAC Fan Coil Units: Primary heat exchange coil for commercial and residential fan coil systems, delivering efficient heating and cooling in centralized air conditioning architectures.
- Chilled Water Systems: Integration into chilled water distribution networks for large-scale commercial buildings, hospitals, and institutional facilities.
- Refrigeration Systems: Use as evaporator or condenser coil elements in commercial refrigeration and cold storage applications.
- Process Cooling: Application in industrial process control systems requiring precise temperature regulation with corrosion-resistant components.
- Food & Beverage Industry: Sanitary-grade heat exchangers in dairy processing, brewing, and pharmaceutical manufacturing where hygienic standards are paramount.
- Marine & Offshore: Corrosion-resistant coil assemblies for marine HVAC systems exposed to high-salinity environments.
- Renewable Energy Systems: Heat recovery coils in heat pump systems and solar thermal installations.
Unique Selling Points
Engineering Excellence for Thermal Performance: Wenzhou Jixing Metal Materials Co., Ltd. leverages advanced coil-forming technology and premium austenitic stainless steel grades to deliver coil tubes that combine superior corrosion resistance with optimal thermal conductivity. The precision-manufactured geometry ensures uniform flow distribution and minimal pressure drop across the coil face, directly translating to reduced fan energy consumption and enhanced system efficiency. The product's versatility in configuration—supporting multiple row counts, fin types, and dimensional variants—enables seamless integration into diverse fan coil unit designs and HVAC system architectures, from compact residential units to large-scale commercial installations.
- Full traceability from raw material to finished product with comprehensive documentation
- Customizable geometry to match specific fan coil unit design requirements
- Extended service life exceeding 25 years under normal operating conditions
- Low maintenance requirement due to inherent corrosion resistance of stainless steel
- Environmentally sustainable — fully recyclable material with zero chlorine or fluoride emissions
Quality Certifications & Compliance
The product line adheres to internationally recognized quality management systems and industry standards, ensuring consistent performance and regulatory compliance:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001:2015 — Environmental Management System certification
- ASTM A213 / A269 — Seamless and welded austenitic stainless steel tubing standards
- EN 10216 — European standard for seamless and welded heat exchanger tubes
- GB/T 12771 — Chinese national standard for stainless steel welded tubes for fluid transport
- ASME B31.5 — Compliance with pressure vessel and piping code requirements
- NSF/ANSI 61 — Drinking water system components certification (where applicable)
- CE Marking — Conformity with European health, safety, and environmental protection standards
- Mill Test Reports (MTR): Provided with every shipment, documenting chemical composition, mechanical properties, and traceability information
Each production batch is subjected to rigorous incoming material inspection, in-process quality control, and final product verification, ensuring that every coil tube delivered meets the exacting specifications required for reliable fan coil unit operation in critical HVAC applications.