Stainless Steel Coil Tube (Coiltube) for Fan Coil Unit Systems
Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered tubing product designed specifically for HVAC (Heating, Ventilation, and Air Conditioning) applications, with particular emphasis on Fan Coil Unit (FCU) systems. This product represents the integration of advanced stainless steel forming technology with modern Building Information Modeling (BIM) assembly methodologies, enabling prefabricated, modular installation of coil assemblies that reduce on-site labor, minimize construction errors, and accelerate project timelines.
The coil tube serves as the core heat exchange element within fan coil units, facilitating efficient thermal transfer between refrigerant or hydronic fluids and the airstream. Wenzhou Jixing Metal Materials Co., Ltd. produces these coil tubes to exacting standards that align with international BIM-based assembly protocols, ensuring compatibility with prefabricated installation frameworks.
Material & Properties
Material Composition
- Primary Material: Austenitic Stainless Steel — Grade 304 (UNS S30400) and Grade 316L (UNS S31603) available
- Alternative Options: 316 (UNS S31600), 321 (UNS S32100), 347 (UNS S34700)
- Alloying Elements: Chromium (Cr) 18–20%, Nickel (Ni) 8–12%, Molybdenum (Mo) 2–3% (for 316 series), Manganese (Mn) ≤2%, Carbon (C) ≤0.08%
- Surface Finish: 2B (Cold Rolled and Annealed), No. 4 Brushed, or Mirror Polish (8K) depending on application requirements
Mechanical Properties
| Property | Grade 304 | Grade 316L |
|---|---|---|
| Tensile Strength (UTS) | ≥515 MPa | ≥485 MPa |
| Yield Strength (0.2% Offset) | ≥205 MPa | ≥170 MPa |
| Elongation at Break | ≥40% | ≥40% |
| Hardness (Brinell) | ≤201 HB | ≤201 HB |
| Density | 7.93 g/cm³ | 7.98 g/cm³ |
| Thermal Conductivity (at 100°C) | 16.3 W/(m·K) | 14.6 W/(m·K) |
| Thermal Expansion Coefficient (20–100°C) | 17.3 × 10⁻⁶ /°C | 16.0 × 10⁻⁶ /°C |
| Operating Temperature Range | −196°C to +870°C | −196°C to +870°C |
Corrosion Resistance
- Excellent resistance to atmospheric corrosion, mild acids, and alkaline environments
- Grade 316L provides superior pitting and crevice corrosion resistance due to molybdenum addition
- Pitting Resistance Equivalent Number (PREN): Grade 304 — 18–20; Grade 316L — 24–26
- Compliant with ASTM A213/A213M standards for corrosion-resistant stainless steel tubes
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Product Code | 562 |
| OD (Outer Diameter) Range | 6.0 mm – 38.1 mm (¼" – 1½") |
| Wall Thickness Range | 0.3 mm – 2.0 mm |
| Coil Winding Diameter | 50 mm – 500 mm (adjustable per FCU design) |
| Coil Length (Unwound) | 1 m – 50 m (customizable) |
| Coil Pitch / Spacing | 3 mm – 15 mm (adjustable for heat transfer optimization) |
| Tolerance on OD | ±0.05 mm (Precision grade) / ±0.1 mm (Standard grade) |
| Tolerance on Wall Thickness | ±10% of nominal |
| Maximum Operating Pressure | 1.6 MPa (standard) / 4.0 MPa (reinforced) |
| Maximum Operating Temperature | 200°C (hydronic) / 60°C (refrigerant side) |
| End Treatment | Plain end / Flared / Soldered / Brazed / Threaded (G, BSP, NPT) |
| Surface Treatment | Pickled & Passivated (P&P), or custom finish |
| Standards Compliance | ASTM A213, ASTM A269, EN 10217-7, GB/T 12771, JIS G3459 |
| Minimum Order Quantity | 500 pieces (standard) / Custom (project-based) |
Manufacturing Process
Process Flow
- Raw Material Procurement: High-purity stainless steel strip (coil) sourced from certified mills, verified for chemical composition via Spectrographic Analysis (OA/SA) and mill test certificates (MTC).
- Slitting & Leveling: Master coils slit to precise width using CNC-controlled slitting lines; subsequently leveled to eliminate coil set and ensure flatness within 0.1 mm/m.
- Forming (Cold Bending / Seaming): Strip formed into round tube profile via roll-forming or helical winding with TIG (Tungsten Inert Gas) continuous welding. Weld seam quality controlled per AWS D10.9M standards.
- Coil Winding: Formed tube wound onto precision CNC-controlled coil winding machines with programmed pitch, diameter, and layer count. Tension-controlled winding ensures uniform geometry without deformation.
- Heat Treatment: Solution annealing at 1050–1150°C followed by water quench to restore full austenitic microstructure and maximize corrosion resistance.
- Pickling & Passivation: Acid cleaning to remove oxide scale; passivation treatment to form protective chromium oxide layer (Cr₂O₃) enhancing passive film integrity.
- End Finishing: Cutting, deburring, and end-forming (flaring, threading, or port welding) according to customer specifications.
- Quality Inspection: Non-Destructive Testing (NDT) including dye penetrant inspection (DPI) on weld seams, hydrostatic pressure testing at 1.5× working pressure, dimensional verification via CMM (Coordinate Measuring Machine), and visual surface inspection.
- Packaging & Shipping: Protective wrapping, desiccant inclusion, and export-grade crating per ISPM-15 standards.
BIM Integration for Prefabricated Installation
In alignment with BIM-based assembly methodologies (as referenced in the technical literature on Fan Coil Unit prefabricated installation), Wenzhou Jixing Metal Materials Co., Ltd. provides coil tubes with pre-defined connection geometries, port orientations, and dimensional data compatible with BIM modeling software (Autodesk Revit, Bentley Systems, etc.). This enables:
- Clash Detection: Pre-installation verification of spatial compatibility between coil assemblies and structural elements
- Prefabrication Accuracy: Factory-assembled coil modules matching BIM models with tolerance ≤±1 mm
- 4D Scheduling: Integration of coil tube delivery schedules with construction project timelines
- Reduced On-Site Fabrication: Elimination of field welding and fitting, reducing installation time by 40–60%
Applications
- HVAC Fan Coil Units (FCU): Primary application — heat exchange coils for commercial and residential air conditioning systems
- VRF/VRV Systems: Variable Refrigerant Flow systems requiring high-efficiency coil elements
- Industrial Process Cooling: Chilled water coils for process temperature control in food processing, pharmaceutical, and chemical industries
- Marine HVAC: Corrosion-resistant coils for marine air conditioning systems (Grade 316L recommended)
- Data Center Cooling: High-density coil assemblies for precision cooling in server rooms
- Medical Facilities: Cleanroom HVAC coils requiring hygienic, non-contaminating materials
- Chilled Beam Systems: Indirect evaporative cooling coils in radiation cooling systems
- Refrigeration Evaporators: Low-temperature coil assemblies for cold storage and freezer applications
Quality Certifications & Standards
| Certification / Standard | Description |
|---|---|
| ISO 9001:2015 | Quality Management System certification ensuring consistent product quality and process control |
| ISO 14001:2015 | Environmental Management System certification |
| CE Marking | European Conformity for market access within the European Economic Area |
| ASTM A213/A213M | Standard specification for seamless and welded austenitic stainless steel tubes for high-temperature service |
| ASTM A269/A269M | Standard specification for austenitic stainless steel seamless, welded, and heavily cold-worked corrosion-resistant tubing |
| EN 10217-7 | European standard for heat exchanger tubes made of non-ferrous metals and alloys |
| GB/T 12771 | Chinese national standard for welded austenitic stainless steel tubes for general use |
| ASME B31.5 | Pressure Piping — Hydraulic Power Transmission (applicable for high-pressure coil applications) |
| Third-Party Inspection | Available upon request (SGS, Bureau Veritas, TÜV, Intertek) |
Unique Selling Points
- BIM-Compatible Geometry: Pre-engineered coil dimensions and port configurations designed for seamless integration with BIM-based prefabricated installation workflows, reducing on-site errors and accelerating project delivery.
- Precision Manufacturing Tolerance: ±0.05 mm OD tolerance ensures consistent heat transfer performance and compatibility with prefabricated mounting brackets and end plates.
- Full Traceability: Each coil tube batch is traceable to raw material mill certificates, with complete heat treatment and NDT records provided.
- Customizable Coil Configuration: Flexible winding parameters (pitch, diameter, layer count, total length) to match specific FCU thermal load requirements and BIM model specifications.
- Superior Corrosion Performance: Pickled and passivated surface treatment ensures long service life (>25 years) in humid HVAC environments without degradation of thermal efficiency.
- Energy Efficiency: Optimized coil geometry maximizes surface-to-volume ratio, achieving U-values exceeding 120 W/(m²·K) for hydronic applications.
Technical Reference
Reference Literature: 《基于BIM的风机盘管装配式安装方案研究》 — Research on BIM-Based Fan Coil Unit Prefabricated Installation Scheme. This study validates the technical feasibility and economic advantages of integrating BIM technology with prefabricated coil tube assembly methods, demonstrating a 40–60% reduction in installation time and significant improvement in on-site construction quality through digital pre-assembly workflows.
Manufacturer Information
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.
Product Category: Stainless Steel Coil Tubes for HVAC Applications
Product Code: 562
Documentation Classification: Technical Literature / Learning Reference