Stainless Steel Coil Tube — Wenzhou Jixing Metal Materials Co., Ltd.
Product Overview
The Stainless Steel Coil Tube (Product No. 494) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered seamless or welded stainless steel tube supplied in continuous coil form. This product is designed for high-performance thermal exchange and fluid conveyance applications, particularly in radiant heating systems, fan coil unit (FCU) assemblies, and combined floor radiation cooling and heating networks. The coil form factor enables efficient storage, transportation, and on-site forming, offering significant logistical advantages over conventional cut-length pipe segments.
This product line draws upon advanced research into the thermodynamic performance characteristics of floor radiation heating and fan coil unit combined cooling and heating systems, ensuring that the tube geometry, wall thickness, and material selection are optimized for maximum thermal efficiency and long-term structural integrity under cyclic thermal loading conditions.
Material & Properties
The Stainless Steel Coil Tube is fabricated from austenitic stainless steel grades, selected for their exceptional corrosion resistance, mechanical strength, and thermal conductivity properties. The primary material specifications include:
- Material Grade: SUS304 (UNS S30400) and SUS316L (UNS S31603), conforming to ASTM A213 / ASME SA-213 standards for seamless austenitic stainless steel boiler, heat-exchanger, and similar high-temperature service tubes.
- Corrosion Resistance: The chromium (Cr) and nickel (Ni) alloy composition provides robust resistance to oxidation, pitting, and stress corrosion cracking (SCC) in aqueous and mildly aggressive environments.
- Thermal Conductivity: Austenitic stainless steel exhibits a thermal conductivity of approximately 16.3 W/(m·K) at 20 °C, providing reliable heat transfer performance in radiant floor and fan coil applications.
- Mechanical Properties: Yield strength (Rp0.2) of ≥205 MPa (SUS304) and ≥170 MPa (SUS316L); tensile strength (Rm) of 515–720 MPa; elongation (A) of ≥40%.
- Temperature Range: Suitable for continuous operation from cryogenic temperatures (−196 °C) up to 870 °C in non-oxidizing atmospheres.
- Hygienic Surface Finish: Available in 2B (cold-rolled and annealed), BA (Bright Annealed), and electropolished surface finishes with surface roughness Ra ≤ 0.8 μm.
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (盘管 Coil Tube) |
| Product No. | 494 |
| Manufacturer | Wenzhou Jixing Metal Materials Co., Ltd. |
| Outer Diameter (OD) | Φ6 mm – Φ50 mm (customizable upon request) |
| Wall Thickness | 0.3 mm – 2.5 mm |
| Coil Length | 25 m – 300 m per coil (configurable) |
| Bending Radius | ≥ 3 × OD (cold forming); ≥ 2 × OD (hot forming) |
| Material Grade | SUS304 / SUS316L / SUS321 / SUS310S |
| Surface Finish | 2B / BA / Electropolished / Passivated |
| End Condition | Cut ends with burr-free finishing; optional threaded or flanged ends |
| Applicable Standards | ASTM A213, ASME SA-213, GB/T 14976, EN 10216-5, JIS G3459 |
| Operating Pressure | Up to 2.5 MPa (typical for radiant floor systems) |
| Operating Temperature | −40 °C to +180 °C (design range for HVAC applications) |
| Delivery Form | Continuous coil on wooden or steel spools |
| Customization | OD, wall thickness, coil length, and heat treatment parameters are fully customizable |
Manufacturing Process
The production of the Stainless Steel Coil Tube at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous, multi-stage manufacturing protocol designed to ensure dimensional accuracy, metallurgical homogeneity, and surface quality:
- Raw Material Selection: Virgin stainless steel billets or wire rod from certified suppliers, subjected to incoming chemical composition analysis (spectrometry) and mechanical testing.
- Hot Rolling / Continuous Casting: Billets are reheated and hot-rolled into tube blanks with controlled wall thickness tolerances.
- Piercing & Drawing: The hot-rolled blanks are pierced and cold-drawn through precision dies to achieve the target inner diameter (ID) and outer diameter (OD) specifications.
- Intermediate Annealing: Tubes are solution-annealed at 1050–1150 °C followed by controlled cooling to relieve cold-work hardening and restore full austenitic ductility.
- Pickling & Passivation: The tube surface is acid-pickled to remove oxide scales, followed by passivation treatment to establish a stable chromium oxide passive film.
- Coil Winding & Spooling: The finished tube is wound onto precision spools with controlled tension to prevent ovality, kinking, or residual stress accumulation.
- Final Inspection & Testing: Each coil undergoes hydrostatic pressure testing, dimensional verification, surface defect inspection (magnetic particle or eddy current), and chemical composition verification prior to packaging.
Applications
The Stainless Steel Coil Tube is engineered for demanding thermal management and fluid transport applications, including but not limited to:
- Radiant Floor Heating Systems: The coil form factor allows for efficient serpentine or spiral loop configurations embedded in concrete slabs or screed layers, providing uniform heat distribution with minimal thermal bridging. Research on combined floor radiation and fan coil unit (FCU) systems has demonstrated that stainless steel coil tubes offer superior thermal response times and longevity compared to PEX or copper alternatives in hybrid heating and cooling networks.
- Fan Coil Unit (FCU) Heat Exchangers: Precision coil tubes are formed into finned tube bundles for compact, high-efficiency air-side heat exchangers used in commercial and residential HVAC systems.
- Combined Cooling and Heating Systems: The coil tube's ability to operate efficiently in both heating and cooling modes makes it ideal for dual-function radiant systems that switch between floor heating and floor cooling.
- Process Industry Heat Exchangers: High-temperature and high-pressure heat exchangers in chemical, pharmaceutical, and food processing industries where corrosion resistance is critical.
- Domestic Hot Water & Solar Thermal Systems: Coil tubes used in solar water heater collectors and domestic hot water circulation loops.
- Medical & Pharmaceutical Equipment: Electropolished coil tubes for hygienic fluid conveyance in bioreactors, CIP (Clean-in-Place) systems, and sterilization loops.
- Automotive & Aerospace Thermal Management: Lightweight coil tubes for coolant circuits, fuel lines, and hydraulic systems.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management and compliance framework ensuring that every batch of Stainless Steel Coil Tube meets international standards:
- ISO 9001:2015 — Quality Management System certification covering all manufacturing and quality control processes.
- ISO 14001:2015 — Environmental Management System certification for sustainable manufacturing practices.
- ISO 45001:2018 — Occupational Health and Safety Management System certification.
- CE Marking — Conformity with European Union directives for pressure equipment and construction products.
- Material Certification: Each shipment is accompanied by a Mill Test Certificate (MTC) / EN 10204 3.1 Certificate documenting chemical composition, mechanical properties, and heat treatment records.
- Non-Destructive Testing (NDT): Eddy current testing (ECT) and magnetic particle inspection (MPI) performed per ASTM E309 and ASTM E709 standards.
- Hydrostatic Testing: All coils tested per ASTM A213 requirements with pressure hold times of ≥10 seconds at 1.5 × design pressure.
- Traceability: Full batch traceability from raw material mill certificate through final coil identification, enabling complete supply chain auditability.
Unique Selling Points
- Research-Validated Performance: Product specifications are informed by peer-reviewed research into floor radiation and fan coil unit combined cooling and heating system thermodynamics, ensuring optimized thermal efficiency and system compatibility.
- Coil Form Factor Advantage: The continuous coil delivery format reduces on-site labor, minimizes joint connections (lowering leak risk), and enables flexible routing configurations tailored to specific installation geometries.
- Exceptional Corrosion Resistance: SUS316L grade option provides superior resistance to chlorides and aggressive aqueous environments, extending service life to 25–50 years in typical HVAC applications.
- Full Customization Capability: Wenzhou Jixing Metal Materials Co., Ltd. offers end-to-end customization of dimensions, material grades, surface finishes, and heat treatment parameters to meet project-specific requirements.
- Integrated Quality Assurance: Multi-stage in-process inspection combined with final NDT and hydrostatic testing ensures zero-defect delivery with full material traceability.
Note: This technical specification is based on the product knowledge documentation (Product No. 494, 盘管 Coil Tube) from Wenzhou Jixing Metal Materials Co., Ltd. and incorporates technical insights derived from research on floor radiation heating and fan coil unit (FCU) combined cooling and heating system performance characteristics. Specific project requirements should be discussed with the manufacturer to ensure optimal product configuration and compliance with applicable local codes and standards.