Stainless Steel Coil Tube (Coiltube) — Ice Storage Tank Water Distribution System
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered tubular component specifically designed for integration into ice storage tank (Ice Storage Tank) systems, particularly for water distribution manifolds and heat exchange configurations. This product is engineered to address critical challenges in thermal energy storage systems, including water distribution uniformity, thermal efficiency, and long-term corrosion resistance.
Based on advanced numerical simulation research — specifically the study titled "Numerical Simulation Study on Water Distribution Uniformity of Different Outflow Configurations of Coil-Type Ice Storage Tanks" — this coil tube product is optimized to ensure superior flow uniformity across multiple outflow forms, thereby maximizing the operational efficiency of ice storage systems used in peak-load shifting (Peak Load Shifting) and thermal energy storage applications.
The coil tube is constructed from high-grade austenitic stainless steel and is available in multiple coil diameters, wall thicknesses, and configurations to accommodate diverse system design requirements ranging from commercial HVAC (Heating, Ventilation, and Air Conditioning) systems to industrial thermal energy storage installations.
2. Material & Properties
The coil tube is fabricated from premium austenitic stainless steel grades, selected for their exceptional combination of corrosion resistance, mechanical strength, thermal conductivity, and weldability. The primary material grades include:
- SUS304 / AISI 304 (UNS S30400): The most widely used grade, offering excellent general corrosion resistance, formability, and weldability. Suitable for most ice storage and HVAC applications.
- SUS316 / AISI 316 (UNS S31600): Enhanced chloride and pitting corrosion resistance due to the addition of molybdenum (Mo). Ideal for applications involving treated water or mildly aggressive environments.
- SUS316L / AISI 316L (UNS S31603): Low-carbon variant of 316 with improved resistance to intergranular corrosion (Intergranular Corrosion), recommended for welded assemblies and long-term submerged service.
Key Material Properties
| Property | Specification (SUS304) | Specification (SUS316L) |
|---|---|---|
| Density (kg/m³) | 7,900 | 8,000 |
| Thermal Conductivity (W/m·K) @ 20°C | 16.3 | 14.6 |
| Thermal Expansion Coefficient (×10⁻⁶/K) @ 20–100°C | 17.3 | 16.8 |
| Tensile Strength (MPa, Minimum) | 520 | 485 |
| Yield Strength (MPa, Minimum) | 205 | 170 |
| Elongation (% at Break) | ≥40 | ≥40 |
| Operating Temperature Range (°C) | −196 to +870 | −273 to +870 |
| Chromium (Cr) Content (%) | 18.0–20.0 | 16.5–18.5 |
| Nickel (Ni) Content (%) | 8.0–10.5 | 10.0–14.0 |
| Molybdenum (Mo) Content (%) | — | 2.0–2.5 |
| Carbon (C) Content (%) | ≤0.08 | ≤0.03 |
Surface Finish Options
- 2B Finish: Cold-rolled, annealed, and pickled surface; smooth and non-directional. Suitable for general industrial applications.
- No. 4 Brushed Finish: Directional satin finish; provides aesthetic appeal and moderate corrosion resistance. Commonly used in commercial installations.
- Mirror Finish (8K): High-polish reflective surface; maximum corrosion resistance and visual quality for premium applications.
- Pickled & Passivated: Chemical treatment to remove surface contaminants and form a protective chromium oxide passive layer, enhancing long-term corrosion resistance.
3. Specifications
| Parameter | Specification / Range |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Product Code / Reference | WX-481 |
| Tube Outer Diameter (OD) | 6.0 mm – 50.8 mm (¼" – 2") |
| Tube Wall Thickness | 0.5 mm – 3.0 mm (0.020" – 0.118") |
| Coil Diameter | 100 mm – 600 mm (4" – 24") |
| Coil Length per Spool | 5 m – 100 m (customizable) |
| Coil Pitch (Spacing Between Turns) | 2.0 mm – 15.0 mm (adjustable per design) |
| Material Grades Available | SUS304, SUS304L, SUS316, SUS316L, SUS321, SUS310S |
| Surface Treatment | 2B, No.4 Brushed, Mirror (8K), Pickled & Passivated |
| Manufacturing Standard | ASTM A213, ASTM A269, GB/T 12771, JIS G3459 |
| Pressure Rating | Up to 2.5 MPa (372 psi) @ 20°C (depends on OD/WT) |
| Connection Types | Threaded (Threaded Fitting), Flanged, Socket Weld, Clamp, Butt Weld |
| Custom Fabrication | Yes — Custom coil geometry, bend radius, and configuration available |
| Minimum Order Quantity (MOQ) | Negotiable based on specification |
| Packaging | Wooden pallet with protective wrapping; export-standard packaging available |
4. Manufacturing Process
The production of the stainless steel coil tube follows a rigorous, multi-stage manufacturing process designed to ensure dimensional accuracy, mechanical integrity, and surface quality consistent with international standards.
- Raw Material Selection & Incoming Inspection: Cold-rolled stainless steel coil strip is sourced from certified mill suppliers. Each batch undergoes incoming inspection for chemical composition (via Optical Emission Spectrometry, OES), mechanical properties, and surface quality verification.
- Coil Forming (Tube Coiling): The flat strip is fed through precision coiling equipment where it is progressively formed into a helical coil shape. Critical parameters including coil diameter, pitch, bend radius, and tube roundness are controlled via CNC (Computer Numerical Control) systems to maintain tight tolerances.
- Welding (if applicable): For seamless configurations, the strip is formed and welded longitudinally using TIG (Tungsten Inert Gas) welding under controlled shielding gas (Argon) environments. Weld quality is verified through visual inspection and, where required, radiographic testing (Radiographic Testing, RT) or dye penetrant testing (Dye Penetrant Testing, PT).
- Heat Treatment & Annealing: The formed coil tube undergoes controlled annealing in a protective atmosphere (typically Argon or Nitrogen) to relieve internal stresses, restore ductility, and ensure full austenitic microstructure. Solution annealing is performed at temperatures between 1,050°C and 1,150°C followed by rapid cooling.
- Pickling & Passivation: The annealed product is treated with a nitric acid/hydrofluoric acid pickling solution to remove scale and contaminants. Subsequently, a passivation treatment forms a stable chromium oxide (Cr₂O₃) passive layer on the surface, enhancing corrosion resistance.
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Dimensional & Quality Inspection: Each coil tube is inspected for:
- Outer diameter and wall thickness (using ultrasonic thickness gauges or bore gauges)
- Coil diameter and pitch uniformity
- Surface finish quality (visual and profilometry)
- Hydrostatic pressure testing (Hydrostatic Pressure Testing) at 1.5× working pressure
- Chemical composition verification (OES sampling)
- Packaging & Shipping: Inspected and approved products are wrapped in protective material, secured on wooden pallets, and prepared for domestic or international shipment in compliance with export packaging standards.
5. Applications
The stainless steel coil tube from Wenzhou Jixing Metal Materials Co., Ltd. is engineered for a diverse range of thermal energy management and fluid distribution applications:
- Ice Storage Tank Systems (Ice Storage Tank): The primary application, where the coil tube serves as the water distribution manifold within ice storage tanks used for thermal energy storage. The coil geometry and outflow configuration are optimized based on CFD (Computational Fluid Dynamics) numerical simulations to ensure uniform water distribution and maximize ice formation and melting efficiency.
- Peak Load Shifting (Peak Load Shifting): Ice storage systems utilizing these coil tubes enable shifting of cooling loads from peak to off-peak hours, reducing electrical demand charges and improving grid stability.
- HVAC (Heating, Ventilation, and Air Conditioning) Systems: Used as heat exchange coils, chiller loops, and condenser tubes in commercial and industrial HVAC installations.
- Thermal Energy Storage Systems (Thermal Energy Storage, TES): Integration into latent heat storage (Latent Heat Storage) and sensible heat storage systems for renewable energy applications, solar thermal systems, and industrial waste heat recovery.
- Food & Beverage Industry: Chilling coils and refrigeration piping in food processing, dairy, and beverage production facilities where hygiene and corrosion resistance are paramount.
- Chemical & Pharmaceutical Processing: Heat exchanger coils in chemical reactors, distillation columns, and pharmaceutical manufacturing equipment requiring high-purity, corrosion-resistant tubing.
- Marine & Offshore Applications: Cooling water systems and heat exchange coils in marine propulsion, offshore platforms, and desalination plants, where chloride-resistant grades (SUS316L) are preferred.
- Geothermal Energy Systems: Heat exchange coils in geothermal heat pump systems for building heating and cooling.
6. Unique Selling Points
CFD-Optimized Design: The coil tube geometry and outflow configurations are validated through advanced Computational Fluid Dynamics (CFD) numerical simulations, ensuring superior water distribution uniformity within ice storage tanks — a critical factor for maximizing thermal efficiency and system performance.
- Superior Corrosion Resistance: Austenitic stainless steel grades with chromium oxide passive layer provide exceptional long-term durability in aqueous and mildly corrosive environments, significantly extending service life compared to carbon steel alternatives.
- High Thermal Efficiency: The coil geometry maximizes the heat transfer surface area within a compact volume, enhancing ice formation rates and thermal exchange efficiency in storage tank systems.
- Customizable Configurations: Flexible manufacturing capabilities allow customization of coil diameter, pitch, tube dimensions, and connection types to meet specific system design requirements.
- Multi-Grade Material Availability: A comprehensive range of stainless steel grades (SUS304, SUS316L, SUS321, SUS310S) accommodates diverse environmental and performance requirements.
- Compliance with International Standards: Manufactured in accordance with ASTM, GB, and JIS standards, ensuring global compatibility and regulatory compliance.
- Rigorous Quality Control: Multi-stage inspection including hydrostatic testing, dimensional verification, chemical analysis, and surface quality assessment ensures consistent product reliability.
- Hygienic & Food-Grade Compatible: Available with smooth, sanitary surface finishes suitable for food, beverage, and pharmaceutical applications.
7. Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and adheres to the following international and national standards:
| Certification / Standard | Description |
|---|---|
| ISO 9001:2015 | Quality Management System (Quality Management System) certification ensuring consistent quality and customer satisfaction. |
| ASTM A213 | Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubes for High Temperature Service. |
| ASTM A269 |