Stainless Steel Coil Tube (Coiltube) – Industrial & Aquaculture Temperature Regulation
Product Code: 841 | Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) is a precision-engineered continuous tubular product wound into a compact coil configuration, designed for applications requiring extended heat exchange surface area within confined spatial volumes. This product line is particularly notable for its deployment in factory-based aquaculture systems, where it serves as a critical component in water temperature regulation loops. The coiltube geometry maximizes the ratio of heat transfer surface area to occupied volume, making it an economically and thermally efficient solution for maintaining optimal water temperature in intensive aquaculture ponds.
Wenzhou Jixing Metal Materials Co., Ltd. produces these coil tubes to exacting dimensional and metallurgical tolerances, ensuring consistent hydraulic performance, mechanical durability, and long-term resistance to the corrosive environments typical of aquaculture and industrial fluid handling applications.
2. Material & Properties
The coil tubes are manufactured from high-grade austenitic stainless steel, selected for their superior combination of corrosion resistance, mechanical strength, and thermal conductivity.
- Primary Grades: SUS304 (18/8 stainless steel), SUS316L (low-carbon, molybdenum-enhanced), and SUS321 (titanium-stabilized) per JIS, ASTM, and GB/T standards.
- Corrosion Resistance: Excellent resistance to pitting, crevice corrosion, and chloride-induced degradation — critical for marine and aquaculture water environments with elevated dissolved oxygen and organic content.
- Thermal Conductivity: Approximately 14–16 W/(m·K) for 304 grade; 13–14 W/(m·K) for 316L grade, providing efficient heat transfer for temperature regulation applications.
- Mechanical Strength: Tensile strength ≥ 520 MPa (annealed condition); elongation ≥ 35%, ensuring resistance to cyclic pressure loading and mechanical fatigue.
- Operating Temperature Range: −196°C to +870°C, accommodating both cooling and heating duty cycles.
- Hygienic Surface Finish: Available in 2B, BA (Bright Annealed), and electropolished (Ra ≤ 0.4 μm) finishes to prevent biofilm adhesion and facilitate CIP (Clean-In-Place) sanitation.
3. Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Product Code | 841 |
| Outer Diameter (OD) | 6.0 mm – 50.8 mm (custom sizes available) |
| Wall Thickness | 0.5 mm – 3.0 mm |
| Coil Outer Diameter | 300 mm – 2,000 mm |
| Tube Length per Coil | 10 m – 500 m (configurable) |
| Material Grades | SUS304, SUS316L, SUS321, 304/316L (ASTM A269) |
| Surface Finish | 2B, BA, Electropolished (Ra ≤ 0.4 μm) |
| Manufacturing Standard | ASTM A269 / A270, GB/T 12771, JIS G3446 |
| Operating Pressure | Up to 1.6 MPa (standard); up to 4.0 MPa (heavy-wall) |
| Operating Temperature | −196°C to +870°C |
| End Preparation | Plain end, beveled end, or threaded connection |
| Winding Tolerance | ±0.5 mm (pitch); ±1.0 mm (diameter) |
| Applicable Environment | Freshwater, saltwater, brackish water, chemical process fluids |
4. Manufacturing Process
The production of stainless steel coil tubes follows a rigorous, multi-stage manufacturing workflow designed to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Selection & Inspection: Stainless steel strip (coil) sourced from certified mills (e.g., POSCO, Outokumpu, Tsingshan) undergoes incoming inspection for chemical composition (spectrometric analysis), mechanical properties, and surface quality.
- Strip Annealing & Cleaning: Cold-rolled strip is annealed at 1,050–1,150°C in a controlled atmosphere furnace to relieve residual stresses, followed by acid pickling and passivation to restore full corrosion resistance.
- Tube Forming (ERW or Weldless): The strip is fed through a series of forming rolls to achieve the desired circular cross-section. Electric Resistance Welding (ERW) or seamless capillary forming is employed depending on diameter and wall thickness requirements. Weld seams are ground flush for pressure applications.
- Heat Treatment & Stress Relief: Post-forming solution annealing at 1,010–1,120°C with rapid water quenching ensures full austenitic microstructure and eliminates forming-induced residual stresses.
- Precision Dimensional Control: Cold-drawing or cold-rolling passes bring OD and wall thickness to final tolerances (±0.05 mm for precision grades).
- Coil Winding: The straight tube is wound into a helical coil using automated winding machines with hydraulic tension control to maintain uniform pitch and prevent kinking or distortion.
- Surface Finishing: Optional electropolishing (using H₂SO₄/H₃PO₄ electrolyte) removes the passivation layer and imparts a smooth, hygienic surface finish suitable for food-grade and aquaculture applications.
- Final Quality Control: Each coil is inspected for dimensional accuracy (laser gauge), surface defects (visual + eddy current), pressure testing (hydrostatic at 1.5× working pressure), and chemical composition verification.
5. Applications
5.1 Factory Aquaculture – Temperature Regulation
This is a primary application domain for this product. In intensive aquaculture systems (e.g., recirculating aquaculture systems — RAS), maintaining precise water temperature is essential for species-specific growth optimization, metabolic regulation, and disease prevention. The stainless steel coil tube is installed within aquaculture ponds to serve as the heat exchange medium in both heating and cooling circuits. Key advantages include:
- Superior corrosion resistance in chlorinated and saltwater environments eliminates the need for frequent replacement.
- High surface-area-to-volume ratio enables rapid thermal response to temperature setpoint changes.
- Hygienic electropolished surfaces prevent biofilm formation and pathogen harboring.
- Economic viability demonstrated through comparative analysis against alternative materials (e.g., PVC, galvanized steel), showing lower total cost of ownership over the system lifecycle.
5.2 Additional Applications
- Food & Beverage Processing: Heat exchange coils in pasteurization, sterilization, and temperature-controlled fermentation systems.
- Pharmaceutical Manufacturing: Clean-in-place (CIP) compatible tubing for pharmaceutical fluid transfer and heat exchange.
- Industrial Process Heating/Cooling: Glycol loop coils, steam trace heating, and condensate recovery systems.
- Geothermal & Solar Thermal Systems: Heat collector coils for low-temperature thermal energy harvesting.
- Marine & Offshore Equipment: Subsea fluid transport and heat exchange in corrosive seawater environments.
6. Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework to ensure product conformity and traceability:
- ISO 9001:2015 – Quality Management System certification for consistent production quality.
- ISO 14001:2015 – Environmental Management System for sustainable manufacturing practices.
- GB/T 12771 – Chinese national standard for stainless steel welded tubes for general fluid transport.
- ASTM A269 / A270 – American standards for austenitic stainless steel tubing (seamless and welded).
- JIS G3446 – Japanese Industrial Standard for stainless steel welded tubes.
- NSF/ANSI 61 – Drinking water system components certification (for food-grade applications).
- EN 10217 – European standard for seamless and welded stainless steel tubes.
- MATERIAL TEST CERTIFICATES (MTC): Mill test certificates provided per EN 10204 3.1 for every batch shipment.
7. Unique Selling Points
Cost-Effective Temperature Regulation for Aquaculture: Independent economic comparative studies have demonstrated that stainless steel coil tubes offer a significantly lower total cost of ownership (TCO) compared to alternative materials in factory aquaculture pond temperature regulation. The combination of extended service life (15–20 years vs. 3–5 years for PVC alternatives), minimal maintenance requirements, and consistent thermal performance makes this product a financially sound investment for intensive aquaculture operations.
- Customizable Coil Geometry: Tailored coil diameter, pitch, and tube length configurations to match specific pond dimensions and thermal load requirements.
- Full Material Traceability: Every coil is serialized with batch-level material traceability from raw steel mill to final product.
- Hygienic & Food-Safe: Electropolished surface finish compliant with FDA and EU food contact material regulations (EC 1935/2004).
- Modular System Integration: Pre-fabricated coil assemblies with integrated inlet/outlet fittings enable rapid installation and system scalability.
- Environmental Sustainability: Stainless steel is 100% recyclable with no degradation of properties, supporting circular economy principles in aquaculture infrastructure.