Stainless Steel Coil Tube (Coiltube) — AFCR-04 Fan Coil Unit Grade
Product Overview
The Stainless Steel Coil Tube (Product No. 921) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered coiled tubing product specifically designed for integration into AFCR-04 Fan Coil Unit (FCU) systems. Fan Coil Units are terminal air-handling devices widely deployed in commercial and residential HVAC (Heating, Ventilation, and Air Conditioning) systems. The coil tube serves as the core heat-exchange element within these units, enabling efficient thermal transfer between circulating refrigerant or hot water and ambient air.
This product represents a high-performance solution for HVAC applications where corrosion resistance, thermal conductivity, and mechanical durability are critical requirements. The coiled configuration maximizes surface area within a compact footprint, ensuring optimal heat exchange efficiency in space-constrained installations.
Material & Properties
The coil tube is fabricated from premium-grade Stainless Steel, selected for its exceptional combination of corrosion resistance, thermal stability, and long-term structural integrity. Key material properties include:
- Base Material: Austenitic stainless steel conforming to ASTM A269 / ASTM A312 specifications (grades 304 and 316L available)
- Corrosion Resistance: Superior resistance to pitting, crevice corrosion, and atmospheric degradation, particularly in high-humidity HVAC environments
- Thermal Conductivity: Optimized for efficient heat transfer between the working fluid and the surrounding air stream
- Mechanical Strength: High tensile strength and fatigue resistance to withstand cyclic thermal loading and pressure differentials inherent in fan coil unit operation
- Hygienic Surface Finish: Passivated surface that inhibits microbial growth, ensuring indoor air quality compliance
Compared to traditional copper coil alternatives, the stainless steel construction offers significantly enhanced resistance to chemical attack from cleaning agents, refrigerant additives, and ambient pollutants, extending the service life of the heat exchange assembly.
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Product Code | 921 |
| Designated Application | AFCR-04 Fan Coil Unit |
| Material Grade | ASTM A269 / A312 — Type 304, Type 316L |
| Outer Diameter (OD) | 6.35 mm (1/4"), 9.52 mm (3/8"), 12.7 mm (1/2") — configurable |
| Wall Thickness | 0.5 mm – 1.5 mm (customizable per application) |
| Coil Pitch | 12 mm – 25 mm (application-dependent) |
| Coil Diameter | Customized per AFCR-04 unit housing dimensions |
| Surface Finish | Mirror polished (Ra ≤ 0.4 μm) or matte passivated |
| Operating Temperature Range | −40°C to +250°C (−40°F to +482°F) |
| Maximum Working Pressure | Up to 1.6 MPa (232 psi) — subject to dimensional configuration |
| Standards Compliance | ASTM A269, ASTM A312, EN 10216-5, ISO 3506 |
| Surface Treatment | Acid pickling and passivation (per ASTM A967) |
Manufacturing Process
The production of the stainless steel coil tube follows a rigorous multi-stage manufacturing protocol to ensure dimensional accuracy, material integrity, and surface quality:
- Material Selection & Incoming Inspection: Raw stainless steel seamless tube stock is procured from certified mills and subjected to spectrographic analysis, tensile testing, and visual inspection to verify compliance with ASTM A269/A312 requirements.
- Coil Forming (Cold Bending): The tube is cold-formed into the required coil geometry using precision CNC-controlled coiling equipment. Controlled bending radii prevent material deformation, wall thinning, and stress concentration that could compromise structural integrity.
- Heat Treatment (as applicable): Post-forming stress relief annealing may be applied to eliminate residual stresses introduced during cold forming, ensuring dimensional stability under thermal cycling.
- Surface Finishing: The formed coil tube undergoes acid pickling and passivation treatment to remove scale, oxide films, and contaminants, establishing a protective chromium oxide passive layer on the surface.
- Quality Control & Testing: Each batch undergoes dimensional verification (OD, wall thickness, coil pitch), pressure testing, and visual inspection. Non-destructive testing (NDT) methods including eddy current inspection may be employed to detect subsurface defects.
- Final Assembly & Packaging: Inspected coil tubes are packaged in protective packaging suitable for transport and installation into AFCR-04 fan coil unit assemblies.
Applications
The stainless steel coil tube is engineered for deployment in a diverse range of HVAC and thermal management applications, with primary emphasis on the AFCR-04 Fan Coil Unit system:
- Commercial HVAC Systems: Primary heat exchange element in fan coil units for office buildings, shopping centers, and institutional facilities
- Residential Climate Control: Ducted and ductless fan coil units for premium residential HVAC installations
- Industrial Process Cooling: Chilled water coil assemblies in manufacturing facilities requiring corrosion-resistant heat exchange
- Medical & Cleanroom Environments: Fan coil units in hospitals, pharmaceutical facilities, and laboratories where hygienic standards and corrosion resistance are mandatory
- Marine & Coastal Installations: HVAC systems in environments exposed to salt-laden atmospheres, leveraging the superior corrosion resistance of stainless steel
Quality Certifications & Standards
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management systems and certifications to assure product reliability and regulatory compliance:
- ISO 9001:2015 — Quality Management Systems certification
- ISO 14001 — Environmental Management Systems certification
- ASTM A269 / A312 — Material conformity for stainless steel seamless and welded tubing
- EN 10216-5 — European standard for welded austenitic stainless steel tubes
- ISO 3506 — Chemical composition and mechanical properties of stainless steels
- ASTM A967 — Standard practice for chemical cleaning and passivation of stainless steel parts
Unique Selling Points: The AFCR-04 grade stainless steel coil tube distinguishes itself through its superior corrosion resistance compared to conventional copper coil alternatives, extended service life in aggressive HVAC environments, hygienic surface finish ensuring indoor air quality compliance, and precision manufacturing tolerances that guarantee optimal heat exchange performance within fan coil unit assemblies. The product delivers a compelling total-cost-of-ownership advantage through reduced maintenance frequency and minimal replacement cycles.