Finned Stainless Steel Coil Heat Exchanger (Model JX-1014 Series)
1. Product Overview
The Finned Stainless Steel Coil Heat Exchanger (翅片式盘管换热器), designated as Model JX-1014, is a high-efficiency thermal exchange component engineered by Wenzhou Jixing Metal Materials Co., Ltd. This product integrates a precision-wound stainless steel coil with mechanically or brazed fins to dramatically increase the effective heat transfer surface area. The design philosophy is rooted in the principles of convective heat transfer enhancement, where the addition of fins extends the thermal contact area between the working fluid inside the coil and the external medium (typically air or gas), thereby reducing the overall thermal resistance and improving the coefficient of performance (COP).
Unlike conventional bare-tube heat exchangers, the finned coil configuration achieves heat transfer rates that are typically 3 to 8 times greater than those of unfinned equivalents of the same footprint, making it an indispensable component in compact thermal management systems across industrial, HVAC, and process engineering applications.
2. Material & Properties
2.1 Base Tube Material
- Austenitic Stainless Steel (奥氏体不锈钢): The primary tube material is SAE 304 (UNS S30400) or SAE 316L (UNS S31603) stainless steel, selected for their exceptional corrosion resistance, mechanical integrity at elevated temperatures, and compliance with sanitary and chemical processing standards.
- Alloy Composition (304): Carbon (C) ≤ 0.08%, Chromium (Cr) 18.0–20.0%, Nickel (Ni) 8.0–10.5%, Manganese (Mn) ≤ 2.0%, Silicon (Si) ≤ 1.0%.
- Alloy Composition (316L): Carbon (C) ≤ 0.03%, Chromium (Cr) 16.0–18.0%, Nickel (Ni) 10.0–14.0%, Molybdenum (Mo) 2.0–3.0%, ensuring superior resistance to chloride-induced pitting corrosion.
2.2 Fin Material
- Stainless Steel Fins: Matching 304 or 316L grade fins for full corrosion compatibility with the base tube.
- Aluminum Fins (aluminum-to-steel bonded configurations): Available in AA-3003 (UNS A93003) grade aluminum for enhanced thermal conductivity (k ≈ 140 W/m·K), used in applications where thermal performance is prioritized over uniform alloy composition.
2.3 Key Physical Properties
| Property | SAE 304 (UNS S30400) | SAE 316L (UNS S31603) |
|---|---|---|
| Density (ρ) | 8.00 g/cm³ | 8.03 g/cm³ |
| Thermal Conductivity (k) at 20°C | 16.3 W/m·K | 14.6 W/m·K |
| Thermal Conductivity (k) at 100°C | 17.9 W/m·K | 16.1 W/m·K |
| Specific Heat Capacity (cp) at 20°C | 500 J/kg·K | 500 J/kg·K |
| Thermal Expansion Coefficient (α) at 20°C | 17.3 × 10⁻⁶ /K | 16.4 × 10⁻⁶ /K |
| Yield Strength (σ_y) | ≥ 205 MPa | ≥ 170 MPa |
| Tensile Strength (σ_uts) | ≥ 515 MPa | ≥ 485 MPa |
| Maximum Service Temperature | 870°C (oxidation limit) | 870°C (oxidation limit) |
| Corrosion Resistance (Pitting Resistance Number, PREN) | 19–20 | 24–26 |
3. Technical Specifications
| Parameter | Specification |
|---|---|
| Product Model | JX-1014 Series (Finned Coil Heat Exchanger) |
| Tube Outer Diameter (OD) | 6.0 mm / 8.0 mm / 10.0 mm / 12.0 mm / 16.0 mm / 19.0 mm (customizable) |
| Tube Wall Thickness | 0.5 mm / 0.8 mm / 1.0 mm / 1.2 mm / 1.5 mm |
| Fin Material | Stainless Steel (304/316L) or Aluminum (AA-3003) |
| Fin Height (h_fin) | 5.0 mm / 8.0 mm / 10.0 mm / 12.0 mm / 15.0 mm |
| Fin Thickness (t_fin) | 0.15 mm / 0.20 mm / 0.25 mm / 0.30 mm |
| Fin Pitch (spacing between fins) | 1.5 mm / 2.0 mm / 2.5 mm / 3.0 mm / 4.0 mm |
| Fin Density (fins per inch) | 6 FPI – 16 FPI (Fin Per Inch) |
| Coil Winding Diameter | 50 mm – 500 mm (configurable) |
| Coil Length | 0.5 m – 20.0 m (continuous or discrete segments) |
| Winding Type | Spiral (helical) / Multi-pass serpentine / Single-pass |
| Maximum Operating Pressure | 1.6 MPa (standard) / 4.0 MPa (reinforced) |
| Hydrostatic Test Pressure | 1.5 × Maximum Operating Pressure |
| Operating Temperature Range | -40°C to +450°C (304 grade) / -40°C to +450°C (316L grade) |
| Heat Transfer Efficiency Improvement | 300% – 800% over bare-tube equivalent |
| End Connection Types | Flanged / Threaded (NPT, BSP) / Soldered / Brazed / Welded (TIG) |
| Surface Finish (Tube) | 2B / BA (Bright Annealed) / Mirror (Ra ≤ 0.4 μm) |
| Standard Length Options | 1 m / 2 m / 3 m / 5 m / 10 m / Custom |
| Coating Options | None / Passivated / PTFE-coated fins / Epoxy powder coat |
4. Manufacturing Process
4.1 Process Flow Overview
The manufacturing of the JX-1014 finned coil heat exchanger follows a rigorous, multi-stage production pipeline that ensures dimensional accuracy, metallurgical integrity, and thermal performance consistency:
- Raw Material Procurement & Inspection: Stainless steel seamless tubes conforming to ASTM A213/A269 standards are sourced from certified mills. Incoming materials undergo spectroscopic analysis (OES) for chemical composition verification and ultrasonic testing (UT) for internal defect detection.
- Cutting & Deburring: Tubes are cut to specified lengths using precision sawing or plasma cutting, followed by mechanical deburring and chamfering to eliminate burrs and ensure clean end faces for subsequent joining operations.
- Coil Forming (Bending): Cold bending is performed using CNC-controlled rotary draw bending machines to form the coil geometry with controlled bend radii (typically R ≥ 3D, where D is the tube outer diameter). The bending process is executed under constant temperature conditions to avoid work-hardening and microstructural degradation. Springback compensation is algorithmically applied to achieve dimensional accuracy within ±0.5 mm tolerance.
- Fin Attachment:
- Welded Fins: Individual fin plates are precision-cut and TIG welded (Tungsten Inert Gas) to the tube surface using a pulsed welding process to minimize heat-affected zone (HAZ) distortion. Weld parameters are optimized to achieve full penetration with minimal dilution.
- Brazed Fins: Fins are brazed to the tube using phosphorus-copper brazing alloy (BCuP series) at temperatures of 650–750°C in a protective atmosphere (argon or vacuum) to prevent oxidation.
- Mechanical Attachment (Insert Fins): Pre-slotted fin plates are mechanically inserted and expanded onto the tube using hydraulic or mechanical expanders, creating a tight metal-to-metal bond without the introduction of external filler metal.
- Heat Treatment (Annealing): Post-weld annealing is conducted at 1050–1100°C followed by rapid quenching (water or air) to restore the austenitic microstructure, relieve residual stresses, and maximize corrosion resistance. The annealing cycle is monitored using thermocouples and recorded for traceability.
- Pickling & Passivation: The annealed product undergoes acid pickling (nitric + hydrofluoric acid mixture) to remove oxide scale, followed by passivation treatment to form a stable chromium oxide (Cr₂O₃) protective film on the surface.
- Pressure Testing: Each unit is subjected to hydrostatic pressure testing at 1.5 times the maximum operating pressure for a minimum hold time of 30 minutes, with zero pressure drop permitted. Pneumatic leak testing using helium or nitrogen is performed as a secondary verification.
- Final Inspection & Packaging: Dimensional verification using coordinate measuring machines (CMM), visual inspection of weld quality, and surface roughness measurement are conducted. Products are packaged with desiccant protection and anti-corrosion wrapping for shipment.
5. Applications
The JX-1014 finned coil heat exchanger is deployed across a broad spectrum of thermal management applications where high surface-area-to-volume ratios, corrosion resistance, and compact design are critical:
- Industrial Process Heating & Cooling: Used in chemical processing plants, food and beverage manufacturing, pharmaceutical production, and paper/pulp industries for liquid-to-gas and gas-to-gas heat exchange.
- Oil & Gas Industry: Employed in wellhead cooling, natural gas dehydration systems, and refinery heat recovery units where chloride-containing environments demand 316L stainless steel construction.
- HVAC & Refrigeration Systems: Integrated into air source heat pumps, industrial chillers, and condenser units for high-efficiency thermal exchange in both heating and cooling modes.
- Power Generation: Applied in waste heat recovery systems (WHR), exhaust gas cooling, and steam generation from flue gas in combined cycle power plants.
- Marine Engineering: Utilized in marine engine cooling systems, ballast water treatment, and shipboard HVAC systems where resistance to seawater corrosion is paramount.
- Food & Dairy Processing: Sanitary-grade configurations (mirror finish, Ra ≤ 0.4 μm) are used for milk pasteurization, juice concentration, and brewery heat exchange where hygiene standards (3-A Sanitary Standards) are mandated.
- Electronics & Semiconductor Cooling: Precision finned coils are used for thermal management in high-power electronics, data centers, and semiconductor manufacturing equipment.
- Agricultural & Greenhouse Systems: Applied in crop drying, greenhouse climate control, and livestock housing ventilation systems.
6. Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and the JX-1014 product line conforms to the following international and national standards:
| Standard / Certification | Description |
|---|---|
| ISO 9001:2015 | Quality Management System (QMS) certification covering design, manufacturing, and service processes |
| ISO 14001:2015 | Environmental Management System certification ensuring sustainable manufacturing practices |
| ISO 45001:2018 | Occupational Health and Safety Management System |
| ASME BPV Section I & VIII | American Society of Mechanical Engineers Boiler and Pressure Vessel Code compliance for pressure-containing components |
| EN 10204 3 |