Stainless Steel Coil Tube (Coiltube) — Fan Coil Unit Grade
Product Overview
The Stainless Steel Coil Tube (Coiltube) is a precision-engineered, continuously wound tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Designed primarily for use in Fan Coil Units (FCU) and HVAC (Heating, Ventilation, and Air Conditioning) systems, this coil tube delivers superior thermal conductivity, corrosion resistance, and mechanical integrity under demanding operating conditions. The product is supplied in continuous coil form, enabling efficient downstream processing into finned tubes, heat exchangers, and other thermal management components.
This coil tube has been validated and characterized through rigorous performance testing on Fan Coil Unit Performance Test Benches (风机盘管机组性能试验台), ensuring that every production lot meets or exceeds the thermal and mechanical requirements specified for commercial and industrial HVAC applications.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, selected for its excellent combination of corrosion resistance, weldability, and thermal performance. The following material characteristics define the product:
- Base Material: Austenitic stainless steel (grades including SUS304, SUS316, or equivalent per ASTM/EN standards)
- Corrosion Resistance: Excellent resistance to atmospheric corrosion, condensation water, and mild chemical exposure typical in HVAC environments
- Thermal Conductivity: Optimized for efficient heat transfer in air-to-water and air-to-air heat exchange applications
- Mechanical Strength: Adequate tensile strength and fatigue resistance to withstand pressure cycling and thermal expansion/contraction in FCU operation
- Surface Finish: Smooth internal and external surfaces to minimize flow resistance and facilitate fin attachment
- Hygienic Properties: Non-toxic, non-reactive, and resistant to biofilm formation, suitable for potable water and indoor air quality applications
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Catalog No. | 1322 |
| Material Grade | SUS304 / SUS316 (ASTM A213, ASTM A269) |
| Outer Diameter (OD) | 6.0 mm – 12.7 mm (custom sizes available) |
| Wall Thickness | 0.4 mm – 1.0 mm (tolerance ±0.05 mm) |
| Coil Width | Standard and custom configurations |
| Coil Diameter | 180 mm – 600 mm (inner coil diameter) |
| Surface Treatment | Pickled and Passivated (PP), Bright Annealed (BA) |
| Working Pressure | Up to 1.6 MPa (tested per FCU performance standards) |
| Operating Temperature Range | −40°C to +200°C |
| Tensile Strength | ≥ 520 MPa (SUS304); ≥ 515 MPa (SUS316) |
| Elongation | ≥ 30% |
| Standard Compliance | ASTM A213/A213M, GB/T 12771, EN 10217-7 |
Manufacturing Process
The production of the stainless steel coil tube follows a tightly controlled multi-stage process to ensure dimensional accuracy, material homogeneity, and surface quality:
- Material Selection & Inspection: Virgin stainless steel strip is procured from certified mills and subjected to incoming quality inspection including chemical composition analysis (spectrometry), mechanical property verification, and visual surface examination.
- Slitting & Leveling: The strip is slit to precise width tolerances and leveled to eliminate coil set, ensuring uniform forming behavior in downstream processes.
- Precision Winding & Forming: The strip is wound into tube form using high-precision CNC-controlled winding equipment. Wall thickness uniformity is maintained through real-time thickness monitoring systems.
- Welding (if applicable): Longitudinal weld seams are produced using automatic TIG (Tungsten Inert Gas) or orbital welding processes with full penetration and minimal heat-affected zone.
- Heat Treatment: Solution annealing is performed at 1050°C–1150°C followed by controlled cooling to restore full austenitic structure, eliminate residual stresses, and maximize corrosion resistance.
- Pickling & Passivation: The tube surface is cleaned of oxide scale through acid pickling, followed by passivation to form a protective chromium oxide film (Cr₂O₃), enhancing long-term corrosion resistance.
- Performance Testing: Each production batch undergoes validation on a Fan Coil Unit Performance Test Bench, evaluating heat transfer coefficient, pressure drop, air-side and water-side thermal performance, and acoustic characteristics under nominal and extreme operating conditions.
- Final Inspection & Coiling: Dimensional verification (OD, wall thickness, straightness), surface quality assessment, and hydrostatic pressure testing are completed before final coiling and packaging.
Applications
The stainless steel coil tube is designed for a broad spectrum of thermal management and fluid conveyance applications:
- Fan Coil Units (FCU): Primary application — used as the core heat exchange element in commercial and residential HVAC systems for space heating and cooling.
- Chilled Water Systems: Heat exchangers in central air conditioning and refrigeration systems.
- Industrial Heat Exchangers: Shell-and-tube heat exchangers, condensers, and evaporators in process industries.
- Water Heating Systems: Domestic and commercial water heaters, solar thermal collectors.
- Food & Beverage Industry: Sanitary-grade fluid conveyance and heat exchange where hygienic standards are critical.
- Pharmaceutical & Laboratory Equipment: CIP (Clean-in-Place) compatible piping and heat exchange components.
- Marine & Offshore Applications: Corrosion-resistant heat exchange and fluid transfer in marine environments (SUS316 grade).
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring product conformity to international standards:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001 — Environmental Management System Certification
- ISO 45001 — Occupational Health and Safety Management System
- CE Marking — European Conformity for relevant product categories
- ASTM / ASME — Compliance with American Society for Testing and Materials and American Society of Mechanical Engineers standards
- GB/T Standards — Full compliance with Chinese national standards for stainless steel tubes and heat exchanger components
- Third-Party Inspection — Available upon request (SGS, BV, TÜV)
Unique Selling Points
Validated Performance: Every product batch is characterized through Fan Coil Unit Performance Test Bench validation, providing empirical data on heat transfer efficiency, pressure loss, and operational reliability — a level of quality assurance uncommon in the coil tube supply chain.
- Precision Manufacturing: CNC-controlled winding and forming ensure dimensional tolerances within ±0.05 mm, enabling seamless integration into automated fin-tube assembly lines.
- Grade Flexibility: Multiple stainless steel grades available (SUS304, SUS316, SUS321) to match diverse corrosion and temperature requirements without compromising performance.
- Custom Engineering Support: Wenzhou Jixing offers OEM/ODM services with customized OD, wall thickness, coil dimensions, and surface treatments tailored to specific project requirements.
- Supply Chain Reliability: Strategic positioning in Wenzhou, China — a globally recognized hub for stainless steel pipe and tube manufacturing — ensures access to premium raw materials and competitive lead times.
- Traceability: Full lot traceability from raw material mill certification through final product delivery, supporting compliance with GMP, FDA, and PED directives.