Stainless Steel Coil Tube — Model 1510 (HVAC Fan Coil Unit Series)
Product Overview
The Stainless Steel Coil Tube, designated as Model 1510 by Wenzhou Jixing Metal Materials Co., Ltd, is a precision-engineered continuous coil tube product specifically designed for use in Fan Coil Unit (FCU) air conditioning systems and related HVAC (Heating, Ventilation, and Air Conditioning) thermal exchange applications. The coil tube is manufactured as a seamless, continuous spiral-form stainless steel tube that undergoes rigorous heat treatment and dimensional calibration to ensure optimal thermal conductivity, structural integrity, and long-term corrosion resistance in demanding fluid circulation environments.
This product represents a specialized application within the stainless steel tube family, where the coil geometry is integral to maximizing heat transfer surface area within compact installation footprints typical of commercial and residential fan coil unit installations.
Material & Properties
The Model 1510 Coil Tube is fabricated from high-grade austenitic stainless steel, selected for its superior balance of mechanical strength, thermal performance, and resistance to environmental degradation.
- Base Material: Austenitic Stainless Steel (Type 304 / SUS304 / Grade 1.4301), with optional Type 316 / SUS316 (Grade 1.4401) for enhanced chloride resistance in marine or chemically aggressive environments.
- Chemical Composition (Typical — Type 304): Carbon (C) ≤ 0.08%, Chromium (Cr) 18.0–20.0%, Nickel (Ni) 8.0–10.5%, Manganese (Mn) ≤ 2.0%, Silicon (Si) ≤ 0.75%, Phosphorus (P) ≤ 0.045%, Sulfur (S) ≤ 0.030%.
- Mechanical Properties: Tensile Strength ≥ 520 MPa; Yield Strength ≥ 205 MPa; Elongation ≥ 40%; Hardness ≤ 200 HB.
- Thermal Conductivity: Approximately 16.3 W/(m·K) at 20°C, ensuring efficient heat exchange performance.
- Corrosion Resistance: Excellent resistance to atmospheric corrosion, weak acids, alkalis, and organic solvents; Type 316 variant offers superior pitting and crevice corrosion resistance due to Molybdenum (Mo) content of 2.0–3.0%.
- Operating Temperature Range: −196°C to +870°C (continuous service).
- Surface Finish: Bright Annealed (BA) or Pickled and Passivated (P&P), with surface roughness Ra ≤ 0.8 μm for reduced fluid friction and fouling resistance.
Technical Specifications
| Parameter | Specification |
|---|---|
| Product Model | 1510 |
| Product Category | Stainless Steel Coil Tube (盘管 / Coiltube) |
| Outer Diameter (OD) | 6.35 mm (1/4"), 9.52 mm (3/8"), 12.70 mm (1/2"), 15.88 mm (5/8"), 19.05 mm (3/4") |
| Wall Thickness (WT) | 0.50 mm – 1.50 mm (configurable) |
| Coil Pitch / Spacing | 15 mm – 50 mm (adjustable per application requirements) |
| Coil Length per Unit | Up to 120 m (continuous coil) |
| Number of Rows | 1 – 6 rows (configurable for capacity scaling) |
| Material Grade | SUS304 (Standard) / SUS316 (Enhanced Corrosion Resistance) |
| Surface Treatment | Bright Annealed (BA) / Electropolished (EP) / Passivated |
| End Connection Type | Flared, Soldered, Brazed, or Threaded (per customer specification) |
| Pressure Rating | Up to 1.6 MPa (16 bar) working pressure |
| Standards Compliance | ASTM A213 / ASTM A269 / EN 10216-5 / GB/T 12771 |
| Delivery Form | Coiled on spool (standard) or cut-to-length straight sections |
Manufacturing Process
The production of the Model 1510 Stainless Steel Coil Tube follows a precisely controlled multi-stage manufacturing workflow to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Selection: Virgin stainless steel wire rod or seamless tube stock is sourced from certified mills and subjected to incoming chemical analysis and mechanical testing.
- Tube Forming: Seamless tubes are produced via hot rolling followed by cold drawing to achieve precise wall thickness tolerances (±0.05 mm). Alternatively, welded tube processes (automatic submerged arc welding or resistance seam welding) are employed for larger diameters, followed by full heat treatment.
- Coil Bending: Precision CNC-controlled coil winding machines form the continuous tube into the specified spiral geometry, with controlled bending radius to prevent wall thinning or ovalization. Bending radius is maintained at a minimum of 3× the tube OD to preserve structural integrity.
- Heat Treatment (Solution Annealing): The formed coil tube is annealed at 1050°C – 1150°C in a protective atmosphere (hydrogen or vacuum) to relieve residual stresses, restore full austenitic microstructure, and ensure maximum corrosion resistance.
- Pickling and Passivation: Chemical pickling removes oxide scale and surface contaminants, followed by acid passivation to form a protective chromium oxide layer (Cr₂O₃) on the surface, ensuring a minimum passivation film thickness of 10–20 nm.
- Surface Finishing: Bright annealing or electropolishing is applied to achieve the required surface roughness and aesthetic quality.
- Quality Inspection: Each batch undergoes dimensional measurement (OD, WT, coil pitch), hydrostatic pressure testing, visual inspection, and sampling for chemical composition verification and mechanical property testing.
- Packaging and Dispatch: Coils are wrapped in protective film, secured on wooden or steel spools, and palletized for shipment with accompanying material test certificates.
Applications
The Model 1510 Stainless Steel Coil Tube is purpose-engineered for thermal exchange applications where corrosion resistance, thermal efficiency, and compact design are critical:
- Fan Coil Units (FCU): Primary application — serving as the heat exchange coil in commercial and residential HVAC fan coil systems for both heating and cooling circuits.
- Air Handling Units (AHU): Integration into larger air handling systems for temperature regulation in commercial buildings.
- Chilled Water Circulation Systems: Use in chilled water distribution loops where stainless steel corrosion resistance prevents galvanic degradation.
- Industrial Process Cooling: Application in pharmaceutical, food and beverage, and chemical processing plants requiring hygienic, non-reactive heat exchange surfaces.
- Marine HVAC Systems: Type 316 variant deployed in shipboard and offshore HVAC installations where chloride-induced pitting corrosion is a concern.
- Heat Recovery Systems: Utilization in energy recovery ventilators (ERV) and heat recovery chillers for improved system efficiency.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality assurance framework ensuring that the Model 1510 Coil Tube meets international standards:
- ISO 9001:2015 — Quality Management System certification covering all production processes.
- ISO 14001:2015 — Environmental Management System certification.
- CE Marking — Compliance with European Directive requirements for pressure equipment and construction products.
- Material Test Certificates (MTC): EN 10204 Type 3.1 certificates provided per batch, documenting chemical composition, mechanical properties, and heat treatment records.
- Compliance Standards: ASTM A213 (Seamless Austenitic Chromium-Steel Tubing), ASTM A269 (Austenitic Stainless Steel Tubing), EN 10216-5 (Welded Tubes for Heat Exchangers), GB/T 12771 (Chinese National Standard for Welded Stainless Steel Tubes).
- Testing Protocols: Hydrostatic pressure testing per ASTM A530, dimensional verification per ISO 4287, and surface finish measurement per ISO 1302.
Unique Selling Points
- Optimized Thermal Performance: Precision coil geometry with controlled pitch and row configuration maximizes heat transfer coefficient while minimizing pressure drop, achieving up to 15% higher thermal efficiency compared to standard coil designs.
- Superior Corrosion Resistance: Full austenitic microstructure with controlled intergranular carbide precipitation ensures exceptional long-term service life in aggressive fluid environments, with Type 316 option providing pitting resistance equivalent number (PREN) ≥ 24.
- Hygienic Surface Quality: Electropolished finish (Ra ≤ 0.4 μm available) meets FDA and EHEDG standards for food-grade and pharmaceutical applications, eliminating crevice contamination risks.
- Customizable Configuration: Flexible ordering options for OD, wall thickness, coil pitch, row count, and end connection types allow seamless integration into diverse system architectures.
- Full Traceability: Each production batch is accompanied by complete material documentation, enabling full supply chain traceability from raw material mill certificate to final delivery.
- Cost-Effective Lifecycle: Stainless steel construction eliminates the need for internal coatings or linings, reducing maintenance costs and extending replacement intervals to 15–25 years of continuous service.
Technical Notes
Installation Guidance: Coil tubes should be installed with adequate support brackets to prevent vibration-induced fatigue. When integrating into fan coil unit assemblies, ensure proper alignment with fin geometry and maintain recommended fluid velocity of 0.5–2.0 m/s within the tube bore to optimize heat transfer while preventing erosion-corrosion. System flushing with deionized water is recommended prior to commissioning to remove manufacturing residues.
Storage and Handling: Coils should be stored indoors or under protective cover in a dry environment. Avoid contact with carbon steel surfaces to prevent galvanic contamination. Handle with appropriate lifting equipment to maintain coil integrity and avoid kinking or deformation.