Stainless Steel Coil Tube (盘管) for HVAC & Fan Coil Unit Systems
Product Overview
The Stainless Steel Coil Tube (盘管/Coiltube), manufactured by Wenzhou Jixing Metal Materials Co., Ltd., is a precision-engineered coiled tubing product specifically designed for integration into Fan Coil Unit (FCU) plus Fresh Air air conditioning systems. This product represents a critical component in modern hydronic and refrigerant-based thermal exchange systems, where the coil tube serves as the primary heat transfer medium between circulating fluids and ambient air streams.
As a coiled configuration of stainless steel tubing, this product offers superior corrosion resistance, thermal conductivity, and mechanical durability compared to conventional carbon steel alternatives. The coil geometry maximizes surface area within a compact footprint, making it ideal for applications requiring high-efficiency heat exchange in constrained installation spaces such as commercial buildings, hospitals, hotels, and industrial facilities.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, ensuring long-term reliability in demanding HVAC environments where exposure to condensate, humid air, and chemical cleaning agents is routine.
Material Grades Available
- SUS 304 (UNS S30408) — General-purpose austenitic stainless steel; balanced corrosion resistance and formability; suitable for most HVAC applications.
- SUS 316 (UNS S31608) — Enhanced corrosion resistance due to 2–3% Molybdenum (Mo) addition; recommended for coastal, chemical, or high-chloride environments.
- SUS 321 (UNS S32108) — Stabilized with Titanium (Ti); resists intergranular corrosion; suitable for elevated-temperature applications.
Key Mechanical & Physical Properties (SUS 304 Reference)
- Tensile Strength (抗拉强度): ≥ 520 MPa
- Yield Strength (屈服强度): ≥ 205 MPa
- Elongation (延伸率): ≥ 40%
- Thermal Conductivity (热导率): 16.3 W/(m·K) at 20°C
- Operating Temperature Range (工作温度范围): −196°C to +870°C
- Corrosion Resistance (耐蚀性): Excellent resistance to atmospheric, aqueous, and food-grade environments
- Surface Finish (表面光洁度): BA (Bright Annealed) or No.4 Brushed finish
Specifications
| Parameter (参数) | Specification (规格) | Unit (单位) |
|---|---|---|
| Outer Diameter (OD) (外径) | Φ9.52 / Φ12.70 / Φ15.88 / Φ19.05 | mm |
| Wall Thickness (壁厚) | 0.40 / 0.50 / 0.60 / 0.70 / 0.80 | mm |
| Coil Pitch (盘管节距) | 12 – 25 | mm |
| Coil Length (盘管长度) | 300 – 3,000 (customizable) | mm |
| Coil Diameter (盘管直径) | 150 – 600 | mm |
| Number of Rows (排数) | 1 / 2 / 3 / 4 / 6 (configurable) | — |
| Fin Type (翅片类型) | Plain / L-Channel / W-Type (aluminum or stainless) | — |
| Fin Density (翅片密度) | 8 – 14 | fins/inch |
| Maximum Working Pressure (最大工作压力) | 1.6 / 2.5 / 4.0 | MPa |
| Hydrostatic Test Pressure (水压试验压力) | 1.5× Working Pressure | MPa |
| End Connection (端部连接) | Threaded (NPT/BSP) / Flanged / Welded / Grooved | — |
| Surface Treatment (表面处理) | Pickling & Passivation (酸洗钝化) | — |
| Product Catalog No. (产品编号) | JX-CT-1019 | — |
Manufacturing Process
The production of the stainless steel coil tube follows a rigorous multi-stage manufacturing protocol to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Selection & Inspection (原材料选取与检验): Cold-rolled stainless steel strip (退火带钢) is sourced from certified mills with full Chemical Composition (化学成分) and Mechanical Property (力学性能) verification per ASTM/EN standards.
- Tube Forming (制管): Precision roll-forming machines shape the strip into seamless or welded tubes with tight dimensional tolerances (±0.05 mm). Welded tubes undergo full-frequency induction welding (高频感应焊接) for uniform weld quality.
- Coil Bending (盘绕成型): Computer-controlled CNC bending systems (数控弯管机) form the tube into the specified coil geometry with consistent pitch and diameter. Minimum bend radius is maintained to prevent wall thinning or ovalization.
- Fin Application (翅片加工): Aluminum or stainless steel fins are mechanically attached to the tube via roll-bonding, welding, or mechanical expansion processes to maximize heat transfer surface area.
- Pickling & Passivation (酸洗钝化): The coil assembly undergoes chemical pickling (removal of scale and oxide) followed by passivation treatment to restore and enhance the protective chromium oxide layer (Cr₂O₃), ensuring optimal corrosion resistance.
- Hydrostatic & Dimensional Testing (水压试验与尺寸检测): Each coil unit is subjected to hydrostatic pressure testing at 1.5× rated working pressure for a minimum of 5 minutes. Laser scanning and coordinate measurement verify dimensional compliance.
- Final Inspection & Packaging (终检与包装): Visual inspection, surface roughness verification, and material certification documentation are completed prior to protective packaging and shipment.
Applications
The stainless steel coil tube finds extensive application in thermal management systems, particularly within the HVAC (Heating, Ventilation, and Air Conditioning) industry. The following academic and practical contexts highlight its significance:
Primary Application Domains
- Fan Coil Unit (FCU) Systems (风机盘管系统): The coil tube serves as the evaporator or condenser element within FCU units, facilitating heat exchange between chilled/hot water (or refrigerant) and supply air. Academic research, such as studies on "Centralized Exhaust Problems in Fan Coil Unit Plus Fresh Air Air Conditioning Systems", underscores the importance of coil tube performance in maintaining indoor air quality (IAQ) and thermal comfort.
- Chilled Water Systems (冷冻水系统): Used as the heat exchange core in air handling units (AHU), fan coil units, and terminal units for commercial and residential buildings.
- Refrigeration & Cooling Systems (制冷与冷却系统): Evaporator coils in walk-in coolers, cold storage, and industrial process cooling.
- Condenser & Boiler Applications (冷凝器与锅炉应用): Heat recovery coils, economizers, and boiler tube banks in power generation and process industries.
- Food & Pharmaceutical Processing (食品与制药加工): Sanitary-grade heat exchangers requiring hygienic surface finishes and corrosion resistance against acidic or alkaline process fluids.
- Marine & Coastal Environments (海洋与沿海环境): SUS 316 grade coils for HVAC systems on offshore platforms, vessels, and coastal infrastructure where chloride-induced corrosion is a concern.
System Integration Considerations
In Fan Coil Unit (FCU) plus Fresh Air systems, the coil tube's thermal performance directly influences the balance between sensible and latent heat removal. Proper coil design—including tube layout, fin density, and flow configuration—ensures adequate dehumidification capacity while minimizing the risk of condensate accumulation and microbial growth on coil surfaces. Centralized exhaust strategies must account for coil performance characteristics to maintain proper air distribution and pressure differentials throughout the building.
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems and ensures all products comply with internationally recognized standards:
Applicable Standards (适用标准)
- ASTM A213/A213M — Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for High-Temperature Service
- ASTM A554/A554M — Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Applications
- EN 10216-5 — Heat Exchanger and Radiator Tubes — Technical Delivery Conditions — Part 5: Non-ferrous Tubes
- ISO 3506-3 — Fasteners Made from Stainless Steel — Part 3: Chemical Composition and Mechanical Properties
- GB/T 14976 — Chinese National Standard for Seamless Stainless Steel Tubes for Fluid Transport
- ASHRAE Standards — Compliance with thermal performance and safety requirements for HVAC components
Quality Certifications (质量认证)
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- ISO 45001:2018 — Occupational Health and Safety Management System
- CE Marking — Conformity with European Union directives for machinery and pressure equipment
- Mill Test Reports (MTR) — Full chemical analysis and mechanical property documentation provided with each batch
- Third-Party Inspection — Available upon request (SGS, Bureau Veritas, TÜV, etc.)
Unique Selling Points (USP)
- Superior Corrosion Resistance: Austenitic stainless steel construction eliminates the need for internal coatings or linings, reducing maintenance costs and extending service life beyond 25 years in typical HVAC applications.
- Customizable Coil Geometry: CNC-precision manufacturing enables bespoke coil configurations tailored to specific FCU models, AHU designs, or OEM requirements, ensuring optimal thermal performance for each application.
- Hygienic Surface Finish: BA (Bright Annealed) or electropolished surfaces minimize bacterial adhesion, making the product suitable for pharmaceutical, food processing, and hospital HVAC applications.
- Energy Efficiency: Optimized fin-and-tube geometry maximizes heat transfer coefficient, reducing fan energy consumption and improving system COP (Coefficient of Performance).
- Full Traceability: Each coil tube carries a unique product identification (JX-CT-1019 series) with complete material traceability from mill certificate to final inspection report.
- Integrated System Knowledge: Backed by academic research into FCU-plus-fresh-air system dynamics, the product design accounts for real-world performance factors including condensate management, air distribution, and pressure balance.
Technical Notes
Note: The selection of coil tube material grade, geometry, and fin configuration should be determined in conjunction with the system design engineer based on specific operating conditions (fluid type, temperature, pressure, flow rate, and environmental exposure). Wenzhou Jixing Metal Materials Co., Ltd. offers complimentary thermal performance simulation and application engineering support for all coil tube orders.