Stainless Steel Coil Tube (Coiltube) – Wenzhou Jixing Metal Materials Co., Ltd.
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) is a precision-engineered continuous tube product manufactured by Wenzhou Jixing Metal Materials Co., Ltd., designed for integration into hydronic heating, cooling, and radiant floor systems. This product is supplied in continuous coil form, enabling efficient downstream processing including cutting, bending, forming, and installation without the need for welded joints. The coil tube is particularly suited for applications in residential and commercial building services systems, including concrete radiant floor heating systems and fan coil unit (FCU) distribution networks, as demonstrated in performance studies conducted in residential buildings along the Yangtze River Basin.
2. Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, providing exceptional corrosion resistance, mechanical strength, and long-term durability in demanding HVAC (Heating, Ventilation, and Air Conditioning) environments.
- Primary Material Grades: SUS304 (ASTM A270 Type 304), SUS316L (ASTM A270 Type 316L) for enhanced chloride resistance
- Corrosion Resistance: Superior resistance to oxidation, pitting, and crevice corrosion in aqueous heating and cooling media
- Thermal Conductivity: Approximately 16.3 W/(m·K) for SUS304 grade, ensuring efficient heat transfer in radiant and convective heating applications
- Operating Temperature Range: −196°C to +870°C (continuous service)
- Maximum Operating Pressure: Up to 1.6 MPa (232 psi) depending on wall thickness and outer diameter
- Surface Finish: Electropolished or passivated inner surface to minimize fouling and maximize hydraulic efficiency
3. Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Product Designation | Stainless Steel Coil Tube (Coiltube) | Internal Catalog No. 661 |
| Material Grade | SUS304 / SUS316L (Austenitic Stainless Steel) | ASTM A270 / GB/T 12771 |
| Outer Diameter (OD) | 6.0 mm – 25.0 mm (customizable) | ±0.1 mm tolerance |
| Wall Thickness | 0.5 mm – 2.0 mm | ±0.05 mm tolerance |
| Coil Length | 30 m – 100 m per coil (standard); up to 200 m available | Continuous coil supply |
| Coil Inner Diameter (Winding) | 150 mm – 600 mm (adjustable to customer requirement) | N/A |
| Surface Condition | Mill finish, electropolished, or passivated | Ra ≤ 0.4 μm (electropolished) |
| Heat Treatment | Solution annealed and water quench | ASTM A270 |
| Hydrostatic Test Pressure | 1.5 × working pressure (minimum) | GB/T 12771 / EN 10217 |
| End Condition | Plain end, beveled end, or pre-flanged (optional) | Custom per order |
| Packaging | Wooden reel or steel frame with protective wrapping | ISO 4180 |
4. Manufacturing Process
The production of the Stainless Steel Coil Tube follows a rigorous multi-stage manufacturing workflow to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Selection: Cold-rolled stainless steel strip sourced from certified mills, verified via spectroscopic analysis for chemical composition compliance (C, Cr, Ni, Mo, Si, Mn content within specified limits).
- Strip Annealing: Continuous annealing in a protective atmosphere (N₂ or H₂) to relieve residual stresses and restore ductility for subsequent forming operations.
- Coil Forming (Rolling): Precision roll-forming on CNC-controlled forming stations to achieve consistent ovality, wall thickness uniformity, and dimensional tolerances along the entire tube length.
- Seam Welding: High-frequency induction welding (HFW) or orbital TIG welding (GTAW) to produce a continuous, defect-free longitudinal seam with minimal heat-affected zone (HAZ).
- Post-Weld Annealing: In-line or batch solution annealing to homogenize the weld zone microstructure, ensuring uniform corrosion resistance throughout the tube.
- Precision Sizing: Multi-stand sizing to achieve final OD and wall thickness within specified tolerances.
- Surface Treatment: Passivation, pickling, or electropolishing to remove scale, contaminants, and chromium-depleted layers, restoring full passive film integrity.
- Quality Inspection: 100% hydrostatic pressure testing, visual inspection, dimensional gauging, and optional eddy current or ultrasonic testing for seam integrity.
- Coiling & Packaging: Winding onto protective reels with moisture-proof wrapping and labeling for traceability.
5. Applications
The Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd. is engineered for a wide range of hydronic and thermal management applications:
- Concrete Radiant Floor Heating Systems: Embedded within concrete slabs as heating distribution piping, providing uniform thermal distribution and long-term durability in residential and commercial buildings. Performance studies along the Yangtze River Basin have validated the efficacy of coil tube systems integrated with concrete radiant floors for energy-efficient space conditioning.
- Fan Coil Unit (FCU) Distribution: Used as heat exchanger tubing and distribution piping in commercial HVAC fan coil systems, leveraging the tube's corrosion resistance and thermal conductivity.
- Industrial Process Heating: Suitable for chemical processing, food and beverage, pharmaceutical, and semiconductor industries requiring hygienic, corrosion-resistant fluid transport.
- Geothermal Heating & Cooling: Deployed in ground-source heat exchanger loops where long-term stability and resistance to soil corrosion are critical.
- Domestic Hot Water Distribution: Sanitary-grade tubing for potable water systems in multi-unit residential and commercial buildings.
- Marine & Coastal Applications: SUS316L grade offers enhanced resistance to chloride-induced corrosion in marine HVAC and desalination systems.
6. Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management systems and holds the following certifications to assure product reliability and regulatory compliance:
- ISO 9001:2015 – Quality Management System Certification
- ISO 14001:2015 – Environmental Management System Certification
- CE Marking – Conformity with European Product Safety Standards (EN 10217-7 for stainless steel tubes)
- GB/T 12771 – Chinese National Standard for welded stainless steel tubes for general applications
- ASTM A270 / ASME SA-270 – Compliance with American material and dimensional specifications
- Material Test Reports (MTR) – Provided with each batch, including chemical analysis, mechanical property data, and hydrostatic test results
- Mill Test Certificates (MTC) – Traceable documentation from raw material mill through final product delivery
7. Unique Selling Points
The Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd. distinguishes itself through the following competitive advantages:
- Continuous Coil Supply: Eliminates field welding requirements, reducing installation time, labor costs, and potential leak points compared to straight-length pipe systems.
- Proven Performance in Radiant Floor Systems: Validated through empirical research on concrete radiant floor heating systems in temperate climates (Yangtze River Basin), demonstrating superior thermal uniformity and energy efficiency.
- Customizable Dimensions: Flexible manufacturing capability accommodating a broad range of OD, wall thickness, and coil length specifications to meet project-specific design requirements.
- Extended Service Life: Austenitic stainless steel construction provides a design life exceeding 50 years in hydronic service, significantly outperforming copper and carbon steel alternatives in corrosive environments.
- Hygienic Surface Quality: Electropolished interior surfaces minimize biofilm formation and particulate accumulation, meeting requirements for food-grade and pharmaceutical applications.
- Full Traceability: Each coil is serialized with complete documentation from raw material through final inspection, ensuring complete supply chain transparency.