Stainless Steel Coil Tube (Coiltube) — Technical Product Specification
Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered tubular product supplied in continuous coiled form. This product is designed to meet the demanding requirements of HVAC (Heating, Ventilation, and Air Conditioning) systems, fluid transport applications, and industrial heat exchanger assemblies. The coil tube is particularly suited for integration into Fan Coil Units (FCUs), where reliable thermal performance, corrosion resistance, and mechanical integrity are paramount.
Unlike straight-length tubing, coil tube is delivered in a continuous helical or serpentine configuration, which significantly reduces downstream processing requirements such as cutting, bending, and welding. This inherent geometry makes the product ideal for applications requiring consistent curvature, such as evaporator coils, condenser coils, and air distribution ducts within commercial and industrial HVAC systems.
Material & Properties
The coil tube is fabricated from austenitic stainless steel grades conforming to international standards including ASTM A269, ASTM A312, and EN 10217. The primary alloying elements—chromium (Cr) and nickel (Ni)—provide exceptional resistance to oxidation, pitting corrosion, and intergranular corrosion under a wide range of environmental conditions.
- Base Material: Austenitic stainless steel (typical grades: 304, 304L, 316, 316L)
- Corrosion Resistance: Superior resistance to atmospheric, chemical, and aqueous corrosion due to the protective chromium oxide passive film
- Mechanical Strength: Adequate tensile strength and ductility to withstand internal pressure differentials and mechanical vibration
- Thermal Conductivity: Moderate thermal conductivity suitable for efficient heat transfer in evaporator and condenser applications
- Hygienic Surface: Smooth interior and exterior surfaces (Ra ≤ 0.8 μm) to minimize fouling and facilitate cleaning in food-grade and pharmaceutical applications
- Temperature Range: Operational suitability from cryogenic temperatures (−196 °C) to approximately 870 °C (depending on grade)
Specifications
| Parameter | Specification |
|---|---|
| Outer Diameter (OD) | 3.0 mm – 25.0 mm (customizable per project requirements) |
| Wall Thickness | 0.3 mm – 1.5 mm (tolerance ±10%) |
| Material Grades | SUS 304, SUS 304L, SUS 316, SUS 316L, SUS 321 |
| Surface Finish | Pickled & Passivated (P&P), No. 4 Brushed, Mirror Polish (optional) |
| Coil Form | Continuous helical coil, serpentine coil, or U-bend coil configurations |
| Coil Length | Up to 100 m per coil (custom lengths available) |
| Applicable Standards | ASTM A269, ASTM A312, EN 10217-7, GB/T 12771 |
| Pressure Rating | Up to 2.0 MPa (design pressure, subject to dimensional configuration) |
| Tolerance | OD: ±0.05 mm; Wall Thickness: ±10%; Straightness: ≤ 1.0 mm/m |
| Minimum Order Quantity (MOQ) | Negotiable per production batch |
Manufacturing Process
The production of stainless steel coil tube at Wenzhou Jixing Metal Materials Co., Ltd follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Selection: Certified stainless steel wire or strip is procured from qualified mills with full chemical and mechanical traceability documentation.
- Forming & Sizing: The raw material is fed through a series of calibrated rollers and dies to form the tube to the specified outer diameter and wall thickness. Continuous dimensional monitoring ensures tolerance compliance throughout the process.
- Welding (where applicable): For seamless alternatives, the tube is formed around a mandrel and longitudinally welded using TIG (Tungsten Inert Gas) welding with inert gas shielding to prevent oxidation. Weld seams are ground smooth to minimize turbulence and stress concentration.
- Pickling & Passivation: The formed tube undergoes acid pickling to remove scale and oxidation products, followed by passivation treatment to restore the chromium-rich passive film, ensuring optimal corrosion resistance.
- Coiling: The finished tube is wound onto a precision coil former to produce the final helical or serpentine coil geometry. Tension control systems ensure uniform coil pitch and prevent deformation.
- Quality Inspection: Each coil undergoes 100% visual inspection, dimensional verification, and non-destructive testing (NDT) including eddy current testing and hydrostatic pressure testing. Chemical composition verification is performed via optical emission spectrometry (OES).
- Packaging & Dispatch: Coils are protected with moisture-proof wrapping, wooden or steel packaging, and shipped with full material test certificates (MTCs) conforming to EN 10204 3.1.
Applications
The stainless steel coil tube is a versatile component with broad application across multiple industries:
- HVAC Systems: Primary application in Fan Coil Units (FCUs) as evaporator and condenser coils; air handling units (AHUs); chiller coils; and heat exchanger assemblies. The continuous coil form eliminates the need for field fabrication, reducing installation time and labor costs.
- Industrial Heat Exchangers: Shell-and-tube heat exchangers, plate-fin heat exchangers, and air-cooled condensers in petrochemical, power generation, and process industries.
- Food & Beverage Processing: Hygienic-grade coil tubing for pasteurization systems, CIP (Clean-in-Place) loops, and beverage transfer lines where corrosion resistance and cleanability are critical.
- Pharmaceutical & Biotechnology: Clean steam distribution, condensate return lines, and process fluid transfer in GMP (Good Manufacturing Practice) compliant facilities.
- Automotive & Transportation: Heat exchanger cores, radiator components, and HVAC systems for commercial vehicles and rail transit.
- Building Services: Radiator loops, underfloor heating circuits, and domestic hot water recirculation systems in residential and commercial construction.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management framework to ensure product conformity and traceability:
- ISO 9001:2015 — Quality Management System certification covering all stages of production
- ISO 14001:2015 — Environmental Management System certification
- Material Test Certificates (MTC) — Provided in accordance with EN 10204 Type 3.1 for every batch
- NDT Compliance — Eddy current testing (ASTM E709), hydrostatic pressure testing (ASTM A269/A312), and visual inspection per ISO 17637
- CE Marking — Product conformity with European directives for relevant applications
- API Certification — Available for industrial and oil & gas applications (upon request)
- Third-Party Inspection — Independent verification available through SGS, Bureau Veritas, or TÜV upon customer request
Unique Selling Points
- Ready-to-Install Coil Geometry: Eliminates field bending, cutting, and welding, reducing installation time by up to 40% and minimizing labor-intensive on-site fabrication.
- Full Traceability: Every coil is accompanied by a complete material test certificate with heat number, chemical analysis, and mechanical test results, ensuring full supply chain traceability.
- Customizable Configurations: Flexible production capability to deliver custom outer diameters, wall thicknesses, coil lengths, and surface finishes tailored to specific project specifications.
- Corrosion-Resistant Longevity: Austenitic stainless steel construction provides a service life exceeding 20 years in most operating environments, significantly reducing lifecycle maintenance costs compared to carbon steel alternatives.
- Hygienic Surface Finish: Pickled and passivated surfaces meet the sanitary requirements of food, beverage, and pharmaceutical industries without additional post-processing.
- Expert Selection Guidance: Drawing on extensive experience in Fan Coil Unit equipment selection and HVAC system design, the manufacturer provides technical consultation to optimize coil tube specifications for peak thermal performance and energy efficiency.
Note: All specifications are subject to confirmation based on the specific project requirements. Customers are advised to provide detailed application parameters—including operating temperature, pressure, fluid medium, and environmental conditions—to receive a tailored product specification from Wenzhou Jixing Metal Materials Co., Ltd.