Stainless Steel Coil Tube — Product Technical Specification (Ref. No. 419)
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd
Product Category: Stainless Steel Coil Tube / Coiltube
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) produced by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered tubular product designed for demanding thermal-hydraulic applications, particularly within Fan Coil Unit (FCU) systems, heat exchangers, and industrial fluid transfer circuits. The product is manufactured in a continuous coil configuration, enabling downstream processing such as cutting, forming, and heat exchanger assembly with minimal material waste and superior dimensional consistency.
This coil tube product line is informed by advanced modeling principles governing mixed thermal-hydraulic characteristics, ensuring that the geometric, material, and surface parameters of the tube are optimized for efficient heat transfer and low-pressure-drop fluid dynamics. The design philosophy integrates insights from computational fluid dynamics (CFD) and thermodynamic modeling to deliver coil tubes that perform reliably under variable operating conditions.
2. Material and Properties
The Stainless Steel Coil Tube is fabricated from high-quality austenitic stainless steel grades, selected to balance corrosion resistance, mechanical strength, and thermal conductivity.
- Primary Grades: AISI 304 (UNS S30400), AISI 316 (UNS S31600), AISI 321 (UNS S32100), and custom alloy compositions upon request.
- Corrosion Resistance: The chromium (Cr ≥ 18%) and nickel (Ni ≥ 8%) content provide excellent resistance to atmospheric, chemical, and thermal oxidation environments. Grade 316 offers enhanced pitting and crevice corrosion resistance due to molybdenum (Mo ≥ 2%) addition.
- Mechanical Properties: Yield strength (Rp0.2) of 205–310 MPa, tensile strength (Rm) of 515–730 MPa, and elongation (A5) of ≥ 35–40%, ensuring ductility during cold forming and coiling operations.
- Thermal Conductivity: Approximately 16.3 W/(m·K) at 20 °C for Grade 304, providing adequate heat transfer performance for thermal-hydraulic applications.
- Operating Temperature Range: −196 °C to +870 °C (Grade 304), with Grade 321 suitable for sustained service above 870 °C due to titanium (Ti) stabilization against intergranular corrosion.
- Surface Finish: Available in 2B (cold-rolled and annealed), No. 1 (hot-rolled), BA (Bright Annealed), and polished finishes (Ra ≤ 0.4 μm) depending on application requirements.
3. Technical Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Outer Diameter (OD) | 3.0 mm – 50.8 mm (customizable) | ISO 9546 / GB/T 14976 |
| Wall Thickness (WT) | 0.3 mm – 3.0 mm (tolerance ±10%) | ISO 9546 / GB/T 14976 |
| Coil Inner Diameter (CID) | 100 mm – 600 mm | Manufacturer standard |
| Coil Length per Roll | 50 m – 200 m (continuous) | Manufacturer standard |
| Roundness Tolerance | ≤ 0.5% of OD | ISO 9546 |
| Wall Thickness Tolerance | ±10% of nominal | GB/T 14976 |
| Straightness | ≤ 1.5 mm per meter | ISO 9546 |
| Surface Roughness (Internal) | Ra ≤ 0.8 μm (standard); Ra ≤ 0.4 μm (polished) | ISO 4287 |
| Hydrostatic Test Pressure | ≥ 3.0 MPa (or as specified per application) | GB/T 14976 |
| Heat Treatment | Solution annealed at 1050–1150 °C followed by water quench | ASTM A213 |
| Coil Packaging | Wooden pallet with moisture-proof wrapping | ISO 4180 |
4. Manufacturing Process
The production of the Stainless Steel Coil Tube at Wenzhou Jixing Metal Materials Co., Ltd follows a rigorous multi-stage manufacturing sequence:
- Raw Material Selection: Certified stainless steel strip or seamless tube blanks are sourced from approved mills, with each batch accompanied by a Mill Test Certificate (MTC) verifying chemical composition and mechanical properties in accordance with ASTM A240 or ASTM A213.
- Cold Forming / Seamless Piercing: For welded coil tubes, precision cold-rolled strip is formed into tubular geometry via a high-speed pipe mill, followed by longitudinal welding using Transferred Arc Welding (TAW) or Laser Welding technology. For seamless variants, hot-rolled blanks are pierced and cold-drawn.
- Heat Treatment: Tubes undergo solution annealing (1050–1150 °C) in a controlled atmosphere furnace to relieve residual stresses and ensure uniform microstructure, followed by rapid water quenching.
- Surface Finishing: Internal and external surfaces are pickled, passivated, and optionally polished to achieve the specified surface roughness and corrosion resistance.
- Dimensional Inspection: Each coil is inspected for outer diameter, wall thickness, roundness, and straightness using ultrasonic thickness gauges, laser diameter sensors, and optical measurement systems.
- Hydrostatic Testing: 100% of coils undergo hydrostatic pressure testing to verify integrity and freedom from porosity or weld defects.
- Coiling and Packaging: Tubes are coiled onto precision-machined cores, wrapped in moisture-barrier film, and secured on wooden pallets for shipment.
5. Applications
The Stainless Steel Coil Tube is engineered for a broad range of industrial and commercial applications, with particular emphasis on thermal-hydraulic systems:
- Fan Coil Unit (FCU) Systems: Serves as the primary heat exchange element in commercial HVAC Fan Coil Units, where the tube geometry and material properties are optimized for mixed thermal-hydraulic performance under variable air and water flow conditions. The coil configuration maximizes surface area-to-volume ratio, enhancing heat transfer efficiency.
- Industrial Heat Exchangers: Used in shell-and-tube heat exchangers, plate-fin coils, and air-cooled condensers in chemical processing, petrochemical, and power generation facilities.
- Refrigeration and Air Conditioning: Employed as evaporator and condenser coils in commercial refrigeration systems, chillers, and heat pump units.
- Process Piping and Fluid Transfer: Utilized in food and beverage processing, pharmaceutical manufacturing, and semiconductor cleanroom systems where corrosion resistance and hygiene standards are critical.
- Automotive and Aerospace: Applied in fuel system tubing, hydraulic lines, and thermal management circuits requiring high-temperature and high-pressure resistance.
- Energy Systems: Deployed in solar thermal collectors, geothermal heat exchange loops, and nuclear cooling circuits where long-term material integrity is paramount.
6. Quality Certifications and Standards
Wenzhou Jixing Metal Materials Co., Ltd maintains comprehensive quality management systems and product certifications to ensure compliance with international standards:
- Quality Management: ISO 9001:2015 certified quality management system covering all production and inspection processes.
- Product Standards:
- ASTM A213 — Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubes for High-temperature Service
- ASTM A269 — Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing
- ISO 9546 — Steel Tubes — General Specifications for Cold-Drawn Steel Tubes
- GB/T 14976 — Fluid Transport Welded Steel Tubes (Chinese National Standard)
- EN 10217 — Technical Delivery Conditions for Cold-Drawn Steel Tubes
- Environmental Compliance: ISO 14001:2015 Environmental Management System certification; products comply with RoHS and REACH directives.
- Material Traceability: Each coil is assigned a unique heat number and batch identifier, enabling full traceability from raw material mill to final delivery.
- Third-Party Inspection: Available upon request through SGS, Bureau Veritas, or TÜV for independent verification of dimensions, chemical composition, and mechanical properties.
7. Unique Selling Points
Thermal-Hydraulic Optimization: The coil tube design incorporates principles derived from mixed thermal-hydraulic characteristic modeling, enabling superior heat transfer coefficients and reduced pressure drop compared to conventional tube geometries. This results in energy-efficient Fan Coil Unit systems and compact heat exchanger designs.
Precision Dimensional Control: Advanced cold-drawing and coiling technology ensures tight tolerances on outer diameter, wall thickness, and roundness, reducing downstream processing costs and improving assembly reliability.
Grade Flexibility: A comprehensive range of austenitic stainless steel grades (304, 316, 321, and custom alloys) allows customers to match material properties precisely to their operating environment — from ambient atmospheric conditions to aggressive chemical or cryogenic applications.
Full Traceability and Certification: Every coil ships with a complete Mill Test Certificate, chemical analysis report, and dimensional inspection record, ensuring regulatory compliance and quality assurance for critical applications.
Scalable Supply: Continuous coil production enables flexible order quantities — from prototype samples to large-volume industrial supply — with consistent quality across all production batches.
8. Conclusion
The Stainless Steel Coil Tube (Ref. No. 419) from Wenzhou Jixing Metal Materials Co., Ltd represents a convergence of advanced metallurgical engineering and thermal-hydraulic system design. By leveraging rigorous manufacturing protocols, internationally recognized quality standards, and application-specific material selection, this product delivers reliable performance across the full spectrum of heat exchange, fluid transfer, and industrial process applications. The integration of mixed thermal-hydraulic modeling principles into the product design ensures that each coil tube is not merely a passive conduit, but an optimized component engineered for maximum efficiency, durability, and service life.