Stainless Steel Coil Tube — HVAC Fan Coil Unit Application Series
Product Overview
The Stainless Steel Coil Tube (Product Code: No. 1129) is a precision-engineered tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd, specifically designed for integration into fan coil unit (FCU) systems and hydronic heating/cooling circuits. As a critical heat-exchange component, the coil tube facilitates efficient thermal transfer between circulating refrigerant or heating medium and the surrounding air stream. The product is engineered to withstand prolonged exposure to varying thermal loads, humidity, and chemical agents commonly encountered in commercial and residential HVAC (Heating, Ventilation, and Air Conditioning) environments.
This product series addresses the specific requirements outlined in industry research regarding the influence of air supply angles on indoor thermal comfort, ensuring that the coil geometry and material properties support optimal airflow distribution and heat dissipation performance across diverse installation configurations.
Material & Properties
The coil tube is fabricated from austenitic stainless steel, selected for its superior combination of corrosion resistance, mechanical strength, and thermal conductivity. The primary material grades employed are as follows:
- Grade 304 (UNS S30408): General-purpose grade with excellent corrosion resistance in atmospheric and mildly corrosive environments. Contains 18% Chromium (Cr) and 8% Nickel (Ni).
- Grade 316 (UNS S31608): Enhanced corrosion resistance due to the addition of 2–3% Molybdenum (Mo), suitable for applications involving chlorinated water or marine environments.
- Grade 316L (UNS S31603): Low-carbon variant of 316, offering improved weldability and resistance to intergranular corrosion in welded assemblies.
Key Material Properties:
- Density: 7.93 g/cm³
- Thermal Conductivity: 14.9–16.3 W/(m·K) at 20°C
- Maximum Service Temperature: 870°C (oxidizing atmosphere)
- Non-magnetic in annealed condition
- Excellent resistance to pitting, crevice, and intergranular corrosion
Specifications
| Parameter | Specification |
|---|---|
| Product Code | No. 1129 |
| Product Name | Stainless Steel Coil Tube (盘管) |
| Material Grade | SUS 304 / SUS 316 / SUS 316L |
| Outer Diameter (OD) | 6.35 mm – 25.4 mm (¼" – 1") |
| Wall Thickness | 0.5 mm – 1.5 mm |
| Coil Length | Custom (typically 1.5 m – 12 m per coil) |
| Coil Diameter | 200 mm – 1500 mm |
| Surface Finish | No. 1 / 2B / BA (Bright Annealed) / Hairline |
| Tolerance (OD) | ±0.1 mm |
| Tolerance (Wall Thickness) | ±10% |
| Maximum Working Pressure | 2.5 MPa (25 bar) |
| Operating Temperature Range | −40°C to +250°C |
| Standard | ASTM A213 / ASTM A269 / GB/T 12771 / EN 10217 |
| End Form | Plain / Beveled / Threaded / Flanged |
| Packaging | Wooden crate / Steel banding with moisture-proof wrapping |
Manufacturing Process
The production of the stainless steel coil tube follows a rigorous multi-stage manufacturing workflow to ensure dimensional accuracy, mechanical integrity, and surface quality:
- Raw Material Selection: Cold-rolled stainless steel strip (CRSS) conforming to ASTM A666 is procured from certified mills. Incoming material undergoes spectroscopic analysis to verify chemical composition.
- Slitting: The strip is slit to precise width using high-precision slitting lines, ensuring uniform edge quality and minimal burr formation.
- Coil Winding / Forming: The slitted strip is wound into coil form using CNC-controlled winding machines. The winding tension is carefully calibrated to prevent deformation and maintain uniform coil diameter.
- Welding (if applicable): Where continuous coil length is required, longitudinal welding is performed via Automatic Argon Arc (TIG) welding with inert gas shielding to prevent oxidation.
- Heat Treatment: Solution annealing is conducted at 1050–1100°C followed by controlled cooling (air or water quench) to relieve residual stresses and restore full austenitic microstructure.
- Surface Finishing: Mechanical polishing, electrolytic polishing, or passivation treatment is applied according to the required surface grade.
- Quality Inspection: Each coil undergoes dimensional verification, pressure testing, visual inspection, and (where specified) non-destructive testing (NDT) including eddy current or ultrasonic examination.
Applications
The stainless steel coil tube is engineered for a broad spectrum of thermal management and fluid transfer applications:
- HVAC Fan Coil Units: Primary heat-exchange coils in commercial and residential air handling systems, where optimized air supply angles and thermal performance are critical for indoor thermal comfort.
- Chilled Water Circulation Systems: Coil assemblies in constant-volume and variable-volume chilled water systems.
- Industrial Heat Exchangers: Shell-and-tube and plate-fin heat exchangers in chemical processing, pharmaceutical, and food-grade applications.
- Refrigeration Systems: Evaporator and condenser coils in commercial refrigeration equipment.
- Marine HVAC: Corrosion-resistant coils for marine and offshore HVAC installations where saltwater exposure is a concern.
- Food & Beverage Processing: Sanitary-grade coil tubing in pasteurization, brewing, and dairy processing equipment.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management framework ensuring compliance with international standards:
- ISO 9001:2015 — Quality Management System certification for consistent product quality and process control.
- ISO 14001:2015 — Environmental Management System certification demonstrating commitment to sustainable manufacturing practices.
- CE Marking (EU) — Conformity with European health, safety, and environmental protection standards.
- ASME Stamp — Pressure vessel and heat exchanger component certification where applicable.
- Mill Test Reports (MTR): Every batch is accompanied by a full chemical and mechanical test report traceable to the mill of origin.
Unique Selling Points:
- Precision coil geometry optimized for uniform airflow distribution and enhanced heat transfer efficiency in fan coil unit configurations.
- Grade flexibility (304/316/316L) enabling application-specific material selection for corrosion-critical environments.
- Full traceability from raw material to finished product, supported by comprehensive documentation and non-destructive testing protocols.
- Customizable dimensions, surface finishes, and end treatments to meet specific OEM and project requirements.
- Thermal performance validated against indoor thermal comfort research parameters, ensuring optimal integration into modern HVAC system designs.