Stainless Steel Coil Tube for HVAC & Fan Coil Units
Product Overview
The stainless steel coil tube manufactured by Wenzhou Jixing Metal Materials Co., Ltd (Product Code: 1582) is a precision-engineered continuous loop tube specifically designed for use in air conditioning systems and fan coil units (FCUs). This coil tube serves as a critical heat exchanger component, facilitating efficient thermal transfer between the refrigerant and ambient air within HVAC (Heating, Ventilation, and Air Conditioning) installations.
Unlike standard straight-length stainless steel tubing, the coil tube is formed into a continuous helical or serpentine configuration, maximizing the surface area-to-volume ratio for optimal heat exchange performance. This design is essential for achieving high energy efficiency ratings in modern air conditioning and ventilation equipment, aligning with international standards such as GB 19576 (Minimum Energy Efficiency Limits for Room Air Conditioners) and ISO 16358 (Energy Performance of Air Conditioners with Split System).
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, selected for its superior corrosion resistance, thermal conductivity, mechanical strength, and long-term durability under demanding HVAC operating conditions.
- Primary Alloy Grades: SUS304 (AISI 304 / 1.4301) and SUS316 (AISI 316 / 1.4401)
- Corrosion Resistance: Excellent resistance to atmospheric corrosion, condensate water, and refrigerant fluids; SUS316 grade provides enhanced resistance to chloride-induced pitting corrosion
- Thermal Conductivity: Approximately 16.3 W/(m·K) at 20°C for SUS304, ensuring efficient heat transfer
- Mechanical Properties: Tensile strength ≥ 520 MPa; yield strength ≥ 205 MPa; elongation ≥ 40%
- Operating Temperature Range: −196°C to +870°C (SUS304); −196°C to +870°C (SUS316)
- Surface Finish: No. 2B, BA (Bright Annealed), or electropolished finish for reduced friction and enhanced heat transfer efficiency
- Hygienic Compliance: Suitable for applications requiring food-grade or pharmaceutical-grade sanitary conditions
Technical Specifications
| Parameter | Specification | Unit |
|---|---|---|
| Outer Diameter (OD) | 6.0 / 8.0 / 9.52 / 12.7 (customizable) | mm |
| Wall Thickness | 0.3 – 1.0 | mm |
| Coil Diameter (Mean) | 150 – 500 (configurable per design) | mm |
| Coil Height / Length | 50 – 3000 (per unit) | mm |
| Number of Turns | 3 – 30 | — |
| Tube Pitch (Center-to-Center) | 12 – 25 | mm |
| Material Grade | SUS304 / SUS316 / SUS321 | — |
| Maximum Working Pressure | 1.6 – 4.0 | MPa |
| Hydrostatic Test Pressure | 6.0 | MPa |
| Surface Roughness (Ra) | ≤ 0.8 | μm |
| Standard Reference | GB/T 14976, ASTM A269, EN 10216-5 | — |
| Connection Method | Brazed / Welded / Flanged / Compression fitting | — |
Manufacturing Process
The production of high-performance stainless steel coil tubes follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, mechanical integrity, and thermal efficiency:
- Material Selection & Incoming Inspection: Raw stainless steel coils are sourced from certified mills and subjected to spectroscopic analysis (PMI) to verify alloy composition compliance with specified grades.
- Pipe Forming (Cold Drawing / Cold Rolling): Flat stainless steel strip is cold-formed into seamless round or oval cross-section tubing using precision forming dies, ensuring uniform wall thickness and dimensional consistency.
- Coil Forming: The formed tube is wound into the required helical or serpentine coil geometry using computer-controlled CNC coil winding machinery, with precise control over coil diameter, pitch, and number of turns.
- Welding (if applicable): Longitudinal seams (for welded tube) are joined using TIG (Tungsten Inert Gas) welding under argon shielding to achieve penetration-free, hermetic welds with minimal heat-affected zone.
- Heat Treatment & Stress Relief: Annealing at 1050–1100°C followed by controlled cooling eliminates residual stresses introduced during cold forming, restoring full austenitic microstructure and mechanical properties.
- Surface Treatment: Pickling and passivation treatment removes scale and oxide layers, forming a protective chromium oxide passive film (Cr₂O₃) that ensures long-term corrosion resistance.
- Quality Testing: Each batch undergoes hydrostatic pressure testing, dimensional measurement (OD, wall thickness, coil diameter), surface inspection, and, where required, radiographic testing (RT) or dye penetrant testing (PT) of weld joints.
Applications
Stainless steel coil tubes from Wenzhou Jixing Metal Materials Co., Ltd are engineered for demanding thermal management applications where energy efficiency, durability, and corrosion resistance are paramount:
- Fan Coil Units (FCUs): Primary heat exchanger coils in residential and commercial FCU systems for space heating and cooling
- Split Air Conditioners: Indoor and outdoor unit evaporator and condenser coil assemblies
- VRF (Variable Refrigerant Flow) Systems: Multi-zone HVAC systems requiring high-performance heat exchange
- Industrial Process Cooling: Chilled water loops, glycol circulation systems, and thermal management in manufacturing facilities
- Food & Beverage Processing: Sanitary-grade heat exchangers for pasteurization, brewing, and dairy processing
- Pharmaceutical Equipment: Clean-in-place (CIP) compatible coil assemblies for sterile manufacturing environments
- Marine & Offshore HVAC: Corrosion-resistant coil tubes for shipboard air conditioning and ventilation systems
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management system and holds the following certifications and compliance credentials:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001:2015 — Environmental Management System certification
- CE Marking — Conformity with European directives for HVAC components
- RoHS Compliance — Restriction of Hazardous Substances in electrical/electronic equipment components
- EN 10204 Type 3.1 — Material test certificates per European standard
- GB/T 19001 — Chinese national standard for quality management
- Energy Efficiency Compliance: Products designed to meet or exceed requirements of GB 19576 (Room Air Conditioners), GB 21454 (Heat Pumps), and ISO 16358 (Energy Performance of Air Conditioners)
Unique Selling Points
1. Superior Energy Efficiency: The precision coil geometry and optimized tube pitch maximize heat transfer surface area, directly contributing to higher Seasonal Energy Efficiency Ratio (SEER) and Energy Efficiency Ratio (EER) ratings in end-use HVAC equipment.
2. Exceptional Corrosion Resistance: Austenitic stainless steel construction eliminates the risk of internal corrosion and scaling that plagues copper and carbon steel alternatives, extending service life beyond 25 years in most operating environments.
3. Hygienic & Food-Grade Compatible: Smooth inner surface finish (Ra ≤ 0.8 μm) prevents microbial colonization and facilitates easy cleaning, making these coils suitable for regulated industries.
4. Customizable Geometries: Flexible manufacturing capability allows tailoring of coil diameter, pitch, tube OD, and wall thickness to match specific OEM heat exchanger designs and energy efficiency targets.
5. Full Traceability: Every production batch is accompanied by material certification and test reports, ensuring complete supply chain traceability and compliance with international procurement standards.
Wenzhou Jixing Metal Materials Co., Ltd is committed to delivering premium-grade stainless steel coil tubes that enable HVAC manufacturers to achieve best-in-class energy efficiency while ensuring long-term reliability and sustainability across diverse global markets.