Stainless Steel Coil Tube (Coiltube) — Fan Coil Unit Thermal Exchange Application
Product Code: 1553 | Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd. | Category: Literature & Technical Reference — Fan Coil Unit Air Conditioner Thermal Performance
Product Overview
The Stainless Steel Coil Tube (Coiltube) is a precision-engineered tubular product designed for use in fan coil unit (FCU) air conditioning systems, serving as a critical component in heat exchange assemblies. This product is specifically developed to meet the rigorous thermal performance requirements identified through experimental research on fan coil unit air conditioners, where coil tube geometry, material conductivity, and surface finish directly influence overall system efficiency.
Coiltube products from Wenzhou Jixing Metal Materials Co., Ltd. are manufactured to strict dimensional tolerances and material specifications, ensuring optimal fluid dynamics within coil assemblies. The coiled configuration maximizes the heat transfer surface area within a compact volume, making it indispensable for commercial and industrial HVAC applications where space constraints and thermal efficiency are paramount.
Material & Properties
The coil tube is fabricated from high-grade stainless steel, selected for its superior combination of corrosion resistance, thermal conductivity, and mechanical strength under cyclic thermal loading conditions.
- Base Material: Austenitic stainless steel conforming to ASTM A213 / ASME SA-213 standards
- Typical Grades: SUS304 (AISI 304), SUS316L (AISI 316L) for enhanced chlorided environment resistance
- Surface Finish: Mill finish or electropolished surface to minimize fouling and maximize heat transfer coefficients
- Corrosion Resistance: Excellent resistance to condensate water, refrigerant fluids, and ambient atmospheric conditions
- Thermal Conductivity: 16.3 W/(m·K) for 304 grade; 14.6 W/(m·K) for 316L grade at 20°C
- Operating Temperature Range: −196°C to +870°C (304 grade); −196°C to +870°C (316L grade)
- Pressure Rating: Designed for system pressures up to 1.6 MPa (standard HVAC loop pressure)
- Hygienic Properties: Non-toxic, non-flavor-imparting, suitable for food-grade and clean-room applications
Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Product Name | Coiltube (盘管) | — |
| Product Code | 1553 | Internal Catalog |
| Tube Outer Diameter (OD) | 9.52 mm / 12.7 mm / 15.88 mm (standard HVAC sizes) | ASTM A213 |
| Tube Wall Thickness | 0.50 mm – 1.00 mm | ISO 1173 |
| Coil Pitch (Spacing) | 12.7 mm – 25.4 mm (adjustable per design) | Manufacturer Specification |
| Coil Bend Diameter | ≥ 3 × tube OD (cold-formed) | ASME B31.9 |
| Coil Length | Custom (standard lengths: 1.0 m, 1.5 m, 2.0 m, 3.0 m) | Customer Requirement |
| Material Grade | SUS304 / SUS316L | ASTM A213 TP304 / TP316L |
| Surface Treatment | Acid pickling, passivation, or electropolishing | ASTM A967 |
| End Finish | Plain, flanged, or threaded (BSP / NPT) | ISO 7 / ASME B1.20.1 |
| Dimensional Tolerance | ±0.1 mm (OD); ±0.05 mm (wall thickness) | ISO 1173 |
| Helical Tolerance | ±0.3 mm (pitch deviation) | Manufacturer Specification |
| Hydrostatic Test Pressure | 1.5 × working pressure (minimum 2.4 MPa) | ASME B31.9 |
Manufacturing Process
The production of stainless steel coil tubes involves a multi-stage precision manufacturing process to ensure dimensional accuracy, structural integrity, and surface quality suitable for thermal exchange applications:
- Raw Material Selection & Inspection: Stainless steel seamless or welded tube stock is procured from certified mills and subjected to incoming inspection including chemical composition analysis (spectroscopy), mechanical property testing, and visual surface examination per ASTM E1426 and ASTM A370.
- Cutting & Deburring: Tubes are cut to required lengths using precision saws with minimal heat input to prevent thermal distortion and intergranular sensitization. End surfaces are deburred and chamfered to ensure smooth fluid entry.
- Coiling (Cold Bending): Straight tubes are formed into helical coils using CNC-controlled coiling machines with tooling designed for the specific tube OD and wall thickness. The bending process is performed at ambient temperature to maintain material metallurgical properties. Bend radii are controlled to prevent wall thinning, ovalization, or wrinkling.
- Heat Treatment (if applicable): For materials requiring stress relief, a controlled annealing cycle is applied at 1050°C followed by rapid air cooling to restore full austenitic microstructure and eliminate residual stresses introduced during cold forming.
- Pickling & Passivation: Coils are subjected to acid pickling (nitric-hydrofluoric acid blend) to remove oxide scales and surface contaminants, followed by passivation treatment per ASTM A967 to restore maximum corrosion resistance through controlled chromium oxide film formation.
- Quality Inspection & Testing: Each coil undergoes dimensional verification (OD, wall thickness, pitch, bend radius), hydrostatic pressure testing, and visual inspection. Non-destructive testing (eddy current or dye penetrant) is performed on weld seams for welded tube stock.
- Packaging & Dispatch: Coils are protected with anti-corrosion wrapping, secured on custom pallets, and shipped with full material traceability documentation including mill certificates and test reports.
Applications
Stainless steel coil tubes are integral components in a wide range of HVAC and thermal management systems:
- Fan Coil Units (FCU): Primary application — serving as heat exchange coils in fan coil air conditioning systems for commercial buildings, hotels, hospitals, and residential complexes. The coil tube geometry directly impacts the thermal performance characteristics studied in experimental research on FCU air conditioners.
- Chilled Water Systems: Used in evaporator coils for chilled water distribution systems in large-scale commercial HVAC installations.
- Heat Pump Systems: Employed in both evaporator and condenser sections of air-source and ground-source heat pump units.
- Refrigeration Equipment: Utilized in medium-temperature and low-temperature refrigeration applications where stainless steel's corrosion resistance provides long-term reliability.
- Food & Pharmaceutical Processing: Hygienic-grade coil tubes used in pasteurization, sterilization, and thermal processing equipment where sanitary requirements are critical.
- Clean Room HVAC: Specified for air handling units in semiconductor manufacturing, biotechnology laboratories, and pharmaceutical clean rooms.
- Marine & Coastal Applications: 316L grade coil tubes deployed in HVAC systems on ships, offshore platforms, and coastal facilities exposed to salt-laden atmospheres.
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring that all coil tube products meet or exceed international standards:
- ISO 9001:2015 — Quality Management System certification for consistent production quality
- ISO 14001:2015 — Environmental Management System certification for sustainable manufacturing practices
- ASTM A213 / ASME SA-213 — Seamless and welded austenitic stainless steel tubing for heat exchangers and heat-transfer equipment
- ISO 1173 — Seamless and welded cold-rolled stainless steel tubes for general engineering purposes
- ASME B31.9 — Pressure piping for refrigeration and air-conditioning systems
- EN 10216-5 — European standard for welded stainless steel tubes for general engineering purposes
- GB/T 14976 — Chinese national standard for seamless stainless steel tubes for hydraulic and pneumatic engineering
- Mill Certification: Each batch accompanied by EN 10204 Type 3.1 material test certificate with full chemical and mechanical property data
- Third-Party Inspection: Available upon request through SGS, Bureau Veritas, or TÜV Rheinland
Unique Selling Points
1. Experimental Research-Validated Performance: Product specifications are informed by and validated against experimental research on fan coil unit air conditioner thermal performance, ensuring that coil tube geometry and material properties are optimized for real-world heat transfer efficiency.
2. Precision Coiling Technology: CNC-controlled coiling ensures consistent pitch, bend radius, and helical accuracy, directly translating to uniform airflow distribution and predictable thermal performance in finished coil assemblies.
3. Material Grade Flexibility: Availability in multiple stainless steel grades (304, 316L, and custom alloys) allows specification matching to specific environmental and corrosion conditions.
4. Full Traceability: Complete material traceability from mill certificate through final product testing provides assurance for regulatory compliance and quality audits.
5. Custom Engineering Support: Capability to manufacture to customer-specific dimensional requirements, including custom coil pitch, tube OD, wall thickness, and end configurations for specialized thermal exchange designs.
Conclusion
The Stainless Steel Coil Tube (Product Code 1553) from Wenzhou Jixing Metal Materials Co., Ltd. represents a technically advanced solution for fan coil unit and HVAC heat exchange applications. Grounded in experimental thermal performance research and manufactured to the highest international standards, this product delivers the reliability, efficiency, and durability required by demanding commercial, industrial, and specialized HVAC systems. Its precise engineering, material quality, and comprehensive quality assurance system make it a preferred choice for OEM manufacturers and system integrators worldwide.