Stainless Steel Coil Tube (盘管 Coiltube) — Finned Heat Exchanger Grade
Product Code: JX-CT-459 | Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.
1. Product Overview
The JX-CT-459 Stainless Steel Coil Tube is a precision-engineered finned coil tube designed for use in high-performance heat exchanger assemblies, particularly in applications involving low-temperature air-side heat transfer. This product line is specifically optimized for configurations where frosting and de-icing behavior directly impacts thermal efficiency and system longevity. Based on extensive experimental research into three-row variable fin spacing (Three-Row Variable Fin Pitch) finned coil tube heat exchanger frosting characteristics, this coil tube integrates design parameters that minimize frost accumulation, reduce pressure drop penalties, and maintain stable thermal performance across extended operating cycles in cold and humid environments.
The coil tube is manufactured from high-grade austenitic stainless steel, ensuring superior corrosion resistance, mechanical integrity, and long-term service life in demanding industrial, commercial, and HVAC (Heating, Ventilation, and Air Conditioning) applications. The continuous coil geometry provides high surface-area-to-volume ratios, enabling compact heat exchanger designs with exceptional heat transfer coefficients.
2. Material & Properties
The base tube material is selected from the following austenitic stainless steel grades, each offering distinct advantages depending on the application environment:
- SUS304 (UNS S30400): General-purpose grade with excellent corrosion resistance and formability. Chromium content ≥ 18%, Nickel content ≥ 8%.
- SUS316 (UNS S31600): Enhanced pitting and crevice corrosion resistance due to Molybdenum addition (2–3%). Ideal for marine, chemical, and coastal environments.
- SUS316L (UNS S31603): Low-carbon variant of 316 with superior resistance to intergranular corrosion. Suitable for welding-intensive assemblies.
- SUS321 (UNS S32100): Titanium-stabilized grade offering excellent resistance to high-temperature oxidation and stress corrosion cracking.
Key Mechanical and Physical Properties (Typical Values for SUS304)
| Property | Value | Standard Reference |
|---|---|---|
| Density (密度) | 8.0 g/cm³ | ASTM A270 |
| Tensile Strength (抗拉强度) | ≥ 515 MPa | ASTM A269 |
| Yield Strength (屈服强度) | ≥ 205 MPa | ASTM A269 |
| Elongation (延伸率) | ≥ 40% | ASTM A269 |
| Thermal Conductivity (导热系数, 100°C) | 16.3 W/(m·K) | ASM Handbook Vol.6 |
| Specific Heat (比热容, 20°C) | 502 J/(kg·K) | ASM Handbook Vol.6 |
| Thermal Expansion Coefficient (热膨胀系数, 20–100°C) | 17.3 × 10⁻⁶ /K | ASM Handbook Vol.6 |
| Maximum Service Temperature (最高使用温度) | 870°C (continuous) | ASTM A270 |
| Corrosion Resistance (耐蚀性) | Excellent against atmospheric, acidic, and alkaline media | ASTM G48 |
3. Specifications
3.1 Base Tube Dimensions
| Parameter | Specification | Unit |
|---|---|---|
| Outer Diameter (外径, OD) | 6.35 / 8.0 / 9.52 / 12.7 (custom available) | mm |
| Wall Thickness (壁厚, WT) | 0.5 / 0.8 / 1.0 / 1.5 (custom available) | mm |
| Inner Diameter (内径, ID) | Calculated per OD − 2×WT | mm |
| Coil Length (盘管长度) | Up to 50 (continuous coil supply) | m |
| Coil Inner Diameter (盘圈内径) | 200 – 1200 (customizable) | mm |
| Surface Finish (表面光洁度) | Mirror polished (Ra ≤ 0.1 μm) / Matte / Commercial | — |
3.2 Fin Configuration (Variable Fin Pitch Design)
The coil tube is available with integrated or post-attached fins, engineered with a three-row variable fin spacing (三排变片距) configuration derived from experimental frosting characterization studies. This design strategically varies the fin pitch (翅片片距) across the three tube rows to manage frost growth patterns and optimize airflow distribution.
| Fin Parameter | Row 1 (Inlet Side) | Row 2 (Middle) | Row 3 (Outlet Side) |
|---|---|---|---|
| Fin Pitch (片距, FP) | 2.0 – 2.5 mm | 2.5 – 3.0 mm | 3.0 – 3.5 mm |
| Fin Thickness (翅片厚度) | 0.10 – 0.15 mm | 0.10 – 0.15 mm | 0.10 – 0.15 mm |
| Fin Height (翅片高度) | 8.0 – 12.0 mm | 8.0 – 12.0 mm | 8.0 – 12.0 mm |
| Fin Material (翅片材料) | Aluminum (6063-T5) / Stainless Steel (SUS304) / Copper-Clad Aluminum | ||
3.3 Performance Characteristics
| Performance Metric | Typical Value / Range |
|---|---|
| Heat Transfer Coefficient (传热系数, Air-Side) | 40 – 90 W/(m²·K) (depending on air velocity and fin geometry) |
| Pressure Drop (压降, Air-Side) | Optimized via variable fin pitch; 15–30% reduction vs. uniform pitch |
| Frosting Mitigation (除霜性能) | Up to 25% delay in critical frost layer formation compared to uniform fin pitch designs |
| Operating Air Temperature Range (适用空气温度范围) | −40°C to +60°C |
| Refrigerant Operating Pressure (制冷剂工作压力) | Up to 4.0 MPa (depending on tube specification) |
| Design Service Life (设计使用寿命) | ≥ 20 years (indoor) / ≥ 15 years (outdoor, corrosion-prone environments) |
4. Manufacturing Process
The production of JX-CT-459 stainless steel coil tubes follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, surface integrity, and metallurgical quality:
- Material Selection & Incoming Inspection (材料选择与来料检验): Stainless steel strip is sourced from certified mills with full chemical composition and mechanical property verification per ASTM A240 / EN 10088-2 standards. Each batch undergoes spectrometric analysis (光谱分析) and hardness testing.
- Slitting & Leveling (分条与矫平): The stainless steel coil is slit to precise width using high-precision slitting lines, followed by leveling to eliminate residual stress and ensure flatness within ± 0.05 mm tolerance.
- Precision Forming & Bending (精密成型与弯管): Cold-rolled strip is formed into round tubes via seamless tube-forming rolls. The continuous coil is then bent into the desired coil geometry using CNC-controlled coil winding machines, maintaining consistent bend radius (弯管半径) and avoiding wall thinning or ovality beyond ± 1% tolerance.
- Welding (焊接): For seamless long-length coil tubes, longitudinal weld seams are produced using Automatic Submerged Arc Welding (SAW, 自动埋弧焊) or Gas Metal Arc Welding (GMAW, 气体保护焊). All welds undergo 100% visual inspection and spot ultrasonic testing (UT, 超声波检测) per ASTM E164.
- Fin Attachment (翅片安装): Fins are attached via precision stamping (涨管法) or brazing (钎焊) processes. For the three-row variable fin pitch configuration, CNC-controlled finning machines program distinct fin spacing for each row to achieve the experimentally optimized frost mitigation profile.
- Surface Treatment & Passivation (表面处理与钝化): Tubes undergo acid pickling (酸洗) and passivation (钝化处理) to remove surface contaminants and restore the passive chromium oxide film. Mirror-polished finishes are achieved through mechanical polishing followed by electrolytic polishing (电解抛光).
- Hydrostatic & Leak Testing (水压试验与气密性测试): Each coil tube undergoes hydrostatic pressure testing (液压试验) at 1.5× the maximum operating pressure per ASTM A269/A270. Leak testing is performed using nitrogen at 0.3 MPa with soapy water or electronic leak detectors.
- Final Inspection & Packaging (终检与包装): Dimensional verification, surface quality inspection, and material certification documentation are completed. Tubes are packaged with protective end caps, moisture-absorbing desiccants, and wrapped in protective film for shipment.
5. Applications
The JX-CT-459 stainless steel coil tube is engineered for a broad range of thermal management applications where corrosion resistance, compact geometry, and frosting performance are critical:
- HVAC & Refrigeration Systems (暖通空调与制冷系统): Air-cooled condensers (风冷冷凝器), evaporators (蒸发器), and heat recovery units (热回收机组) in commercial and industrial HVAC systems, particularly in cold climate regions where frosting is a dominant degradation mechanism.
- Automotive & Transportation (汽车与交通运输): Vehicle cabin HVAC evaporators and condensers, battery thermal management systems for electric vehicles (EV battery cooling/heating coils).
- Food Processing & Cryogenic Systems (食品加工与低温系统): Freezing equipment (速冻设备), refrigerated transport containers (冷藏集装箱), and cryogenic processing lines requiring hygienic-grade stainless steel surfaces.
- Industrial Process Heat Exchangers (工业过程换热器): Air-to-liquid and air-to-air heat exchangers in chemical processing, petrochemical, and pharmaceutical industries where corrosion-resistant materials are mandatory.
- Heat Pump Systems (热泵系统): Outdoor air-source heat pump evaporators (室外机蒸发器) operating in low-temperature, high-humidity environments where frosting management is essential for maintaining COP (Coefficient of Performance, 性能系数).
- Energy Storage & Thermal Management (储能与热管理): Thermal regulation coils for lithium-ion battery packs in stationary energy storage systems (ESS, 储能系统).
6. Quality Certifications & Standards Compliance
JX-CT-459 coil tubes are manufactured and tested in accordance with the following international and national standards:
| Standard / Certification | Scope | Description |
|---|---|---|
| ASTM A269 | Tube Material | Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubes for Chemical and Heat-Transfer Applications |
| ASTM A270 | Tube Material | Standard Specification for General Requirements for Seamless and Welded Austenitic Stainless Steel and Heat-Resisting Steel Tubes and Bars for Boilers and Heat Exchangers |
| EN 10216-5 | Tube Material | Technical Delivery Conditions for Non-Alloy, Heat-Resisting and Stainless Steel Tubes for Mechanical and Technical Purposes |
| GB/T 12771 | Tube Material | Chinese National Standard for Stainless Steel Seamless Tubes for General Purposes |
| ISO 9001:2015 | Quality Management System | Certified Quality Management System covering design, manufacturing, and delivery |
| ISO 14001:2015 |