Stainless Steel Coil Tube (Fan Coil Tube) — Technical Specification
1. Product Overview
The Stainless Steel Coil Tube (Fan Coil Tube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered product designed for use in HVAC (Heating, Ventilation, and Air Conditioning) systems, particularly in fan coil units (FCUs). This product is distinguished by its superior hygienic performance and antimicrobial properties, making it an ideal solution for environments where air quality and sterilization are critical requirements.
Based on extensive research into the sterilization efficacy of disinfection-type fan coil tubes, this product integrates advanced material science with practical engineering design to deliver reliable thermal exchange performance while simultaneously inhibiting the proliferation of bacteria, mold, and other biological contaminants within the air distribution system.
2. Material & Properties
2.1 Base Material
- Primary Alloy: Austenitic Stainless Steel (奥氏体不锈钢), Grade 304 (UNS S30400) or Grade 316 (UNS S31600)
- Key Alloying Elements: Chromium (Cr) 18–20%, Nickel (Ni) 8–12%, Molybdenum (Mo) 2–3% (for 316 grade)
- Carbon Content: ≤ 0.08% (low-carbon variant for enhanced corrosion resistance)
2.2 Mechanical Properties
- Tensile Strength (UTS): ≥ 520 MPa (Grade 304) / ≥ 570 MPa (Grade 316)
- Yield Strength (0.2% Offset): ≥ 205 MPa
- Elongation at Break: ≥ 40%
- Hardness: ≤ 95 HRB (annealed condition)
2.3 Surface & Functional Properties
- Surface Finish: 2B cold-rolled finish, Ra ≤ 0.8 μm
- Corrosion Resistance: Superior resistance to pitting, crevice, and intergranular corrosion
- Hygienic Performance: The austenitic passivation layer (Cr₂O₃) provides inherent antimicrobial surface characteristics, reducing biofilm formation and bacterial adhesion
- Thermal Conductivity: 16.3 W/(m·K) at 20°C
- Operating Temperature Range: −196°C to +870°C
3. Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Product Designation | Coil Tube / Fan Coil Tube (盘管) | — |
| Material Grade | SUS304 / SUS316 / SUS316L | ASTM A213 / ASTM A269 |
| Outer Diameter (OD) | 6.0 mm – 12.7 mm (typical range) | ASME B36.19M |
| Wall Thickness | 0.5 mm – 1.5 mm | ASME B36.19M |
| Coil Pitch (Turn Spacing) | 6.0 mm – 15.0 mm (configurable) | Custom per application |
| Coil Length | Up to 50 m (continuous coil) | — |
| Surface Treatment | Electro-polished / Passivated | ASTM A967 |
| Hygienic Rating | Anti-bacterial surface, low biofilm adhesion | ISO 22196 (antimicrobial testing) |
| Pressure Rating | Up to 1.6 MPa (working pressure) | EN 10217 / ASME B31.9 |
| Welding Method | Orbital TIG (GTAW) / Argon Shielded | ASME B31.9 |
| Product Code | 1534 | Internal catalog |
4. Manufacturing Process
4.1 Production Workflow
- Material Selection & Incoming Inspection: Certified stainless steel strip or seamless tube stock is inspected for chemical composition (spectroscopic analysis) and mechanical properties.
- Forming & Coil Winding: Cold-drawn or seamless tubes are precision-formed into helical coils using CNC-controlled coiling equipment to ensure uniform pitch, diameter tolerance (±0.1 mm), and consistent geometry.
- Welding: Orbital TIG welding (Gas Tungsten Arc Welding, GTAW) is employed for end-to-end joining, ensuring seamless, leak-tight connections with minimal heat-affected zone (HAZ).
- Surface Finishing: Tubes undergo electro-polishing and chemical passivation to remove surface contaminants, refine grain structure, and enhance the passive chromium oxide layer for maximum hygienic performance.
- Hydrostatic Pressure Testing: Each coil assembly is subjected to hydrostatic testing at 1.5× working pressure to verify structural integrity and weld soundness.
- Final Inspection & Packaging: Dimensional verification, visual inspection, and surface quality assessment are conducted before protective packaging for shipment.
4.2 Key Process Advantages
- Continuous coil production eliminates multiple weld joints, reducing failure points
- CNC coiling ensures geometric accuracy and repeatability
- Orbital welding produces aesthetically superior and mechanically robust welds
- Electro-polishing achieves Ra < 0.4 μm surface roughness, critical for hygienic applications
5. Applications
5.1 Primary Application Domains
- Medical & Pharmaceutical Facilities: Fan coil units in operating rooms, cleanrooms, and hospitals where air sterilization is mandatory
- Food & Beverage Processing: HVAC systems in food manufacturing plants requiring hygienic-grade air handling
- Semi-Conductor Manufacturing: Cleanroom environments where particulate and microbial control is essential
- Commercial HVAC Systems: Office buildings, hotels, and public facilities seeking enhanced indoor air quality (IAQ)
- Residential HVAC: Premium residential fan coil units for improved health and comfort
5.2 Performance in Sterilization Context
Research findings indicate that stainless steel coil tubes, due to their inherent passivation layer and smooth surface finish, demonstrate significant antibacterial efficacy compared to carbon steel alternatives. The austenitic stainless steel surface resists biofilm colonization, thereby reducing the risk of Legionella and other pathogenic bacteria proliferation within HVAC systems. This makes the product particularly suitable for disinfection-oriented fan coil unit designs.
6. Quality Certifications & Compliance
6.1 Certifications
- ISO 9001:2015 — Quality Management System
- ISO 14001:2015 — Environmental Management System
- ISO 45001:2018 — Occupational Health and Safety Management
- CE Marking — European Conformity
- SGS Testing Report — Material composition and performance verification
- MTR (Material Test Report) — Full chemical and mechanical analysis per heat lot
6.2 Standards Compliance
- ASTM A213 — Specification for Seamless Austenitic Stainless Steel Tubing
- ASTM A269 — Specification for Seamless and Welded Austenitic Stainless Steel Tubes
- ASME B31.9 — Building Services Piping
- EN 10217 — Technical Delivery Conditions for Stainless Steel Tubes
- GB/T 12771 — Chinese National Standard for Welded Stainless Steel Tubes
- ISO 22196 — Antimicrobial testing of materials
7. Unique Selling Points
- Integrated Hygienic Performance: Unlike conventional coil tubes, this product is specifically engineered to support sterilization functions, reducing microbial contamination risk in HVAC air streams.
- Research-Backed Design: Product development informed by published research on the disinfection efficacy of fan coil tubes, ensuring evidence-based performance claims.
- Corrosion-Free Longevity: Austenitic stainless steel construction ensures decades of service life without corrosion-related degradation, even in high-humidity environments.
- Customizable Configuration: Coil geometry, pitch, and dimensions can be tailored to specific HVAC system requirements.
- Full Traceability: Every product batch is accompanied by complete material traceability documentation and test reports.
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd. (温州吉兴金属材料有限公司)
Product Catalog Code: 1534