Stainless Steel Coil Tube (Coiltube) for Evaporative Cooling Systems
Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered tubular component designed for evaporative cooling applications. This product represents a critical element in thermal management systems where uniform water distribution, efficient heat transfer, and long-term corrosion resistance are paramount. The coil tube is fabricated from high-grade stainless steel and formed into continuous helical configurations that maximize surface-area-to-volume ratios, thereby enhancing evaporative cooling performance under varying airflow velocities and spray water flow rates.
Based on extensive research into the influence of cooling wind speed and spray water volume on the water distribution uniformity of evaporative cooling coil tubes, Wenzhou Jixing Metal Materials Co., Ltd has optimized the geometric parameters, material selection, and manufacturing tolerances of this product to deliver superior thermal-hydraulic performance in industrial and commercial cooling applications.
Material & Properties
The coil tube is constructed from austenitic stainless steel, offering exceptional resistance to corrosion, scaling, and biofouling in wet cooling environments. The primary material grades utilized include:
- 304 Stainless Steel (AISI 304 / EN 1.4301) — General-purpose grade with excellent weldability and corrosion resistance in moderate environments.
- 316L Stainless Steel (AISI 316L / EN 1.4404) — Enhanced pitting and crevice corrosion resistance due to molybdenum addition; preferred for high-chloride or aggressive cooling water conditions.
- 321 Stainless Steel (AISI 321 / EN 1.4845) — Stabilized with titanium for improved resistance to intergranular corrosion at elevated operating temperatures.
Key material properties include:
- Thermal conductivity: 14–16 W/(m·K) at 25°C
- Coefficient of thermal expansion: 16–18 × 10⁻⁶ /°C
- Maximum operating temperature: up to 870°C (continuous)
- Minimum operating temperature: down to cryogenic levels without embrittlement
- Nickel content: 8–10.5% (304); 12–15% (316L)
- Chromium content: 18–20% (304); 16–18% (316L)
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Product Code / Serial No. | 237 |
| Material Grade | 304, 316L, 321 (selectable) |
| Outer Diameter (OD) | 6.0 mm – 50.8 mm (1/4" – 2") |
| Wall Thickness | 0.5 mm – 3.0 mm |
| Coil Pitch | 10 mm – 50 mm (customizable) |
| Coil Length | 0.5 m – 10 m (per coil) |
| Surface Finish | 2B (cold-rolled), BA (bright annealed), or No.4 brushed |
| Manufacturing Standard | ASTM A213 / ASME SA-213 / EN 10216-5 |
| Operating Pressure | Up to 1.6 MPa (standard); up to 4.0 MPa (custom) |
| Operating Temperature Range | -196°C to +450°C (continuous) |
| Water Distribution Uniformity | ≥ 90% (optimized spray pattern) |
| Applicable Cooling Air Velocity | 1.0 – 8.0 m/s |
| Applicable Spray Water Flow Rate | 0.5 – 5.0 L/(m²·min) |
| Welding Method | TIG (GTAW) / Orbital automatic welding |
| End Connection | Threaded (BSP/NPT), Flanged, or Butt-welded |
| Customization | Available upon request (OD, pitch, length, material) |
Manufacturing Process
The production of the stainless steel coil tube follows a rigorous multi-stage manufacturing process designed to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Selection & Inspection: Cold-rolled stainless steel strip or seamless tubing is sourced from certified mills. Incoming material undergoes spectroscopic analysis (PMI) to verify chemical composition, along with mechanical property testing per ASTM E10 (hardness) and ASTM A370 (tensile).
- Forming & Coiling: Precision CNC-controlled coiling machines form the tubing into helical configurations with controlled pitch and diameter tolerances (±0.1 mm). The forming process employs gradual bending to prevent ovalization and maintain circular cross-section integrity.
- Welding: Continuous helical coils are joined using orbital TIG (Gas Tungsten Arc Welding) or longitudinal weld processes. Weld parameters are optimized to minimize heat-affected zone (HAZ) distortion and ensure full penetration with smooth internal weld profiles.
- Heat Treatment & Annealing: Post-forming annealing in a controlled atmosphere furnace (1050°C ± 20°C, air or argon cooling) relieves residual stresses, restores full austenitic microstructure, and ensures maximum corrosion resistance.
- Surface Treatment: Surface finishing (pickling and passivation) removes oxide scale and forms a protective chromium oxide passive layer, critical for long-term corrosion resistance in evaporative cooling environments.
- Quality Inspection: Each batch undergoes hydrostatic pressure testing, dimensional verification, and visual/NDT inspection (dye penetrant or eddy current) to ensure zero-defect delivery.
Applications
The stainless steel coil tube is engineered for demanding thermal management applications where reliability, efficiency, and durability are essential:
- Evaporative Cooling Systems: Primary component in direct and indirect evaporative coolers, where optimized water distribution uniformity ensures peak cooling efficiency across variable airflow conditions.
- Industrial HVAC Systems: Used in large-scale air handling units (AHUs) and rooftop units (RTUs) for commercial and industrial facilities requiring high-capacity cooling.
- Agricultural Cooling: Applied in greenhouse climate control systems and livestock cooling installations where corrosion resistance to ammonia and organic vapors is critical.
- Food & Beverage Processing: Employed in dairy, brewing, and beverage pasteurization systems where hygienic surface requirements and resistance to caustic cleaning agents are mandatory.
- Chemical Processing: Utilized in condensers, coolers, and heat exchangers handling corrosive process fluids in petrochemical and pharmaceutical plants.
- Marine & Offshore Cooling: Deployed in marine air conditioning and engine cooling systems where resistance to saltwater corrosion and biofouling is paramount.
- Data Center Cooling: Integrated into free-cooling systems for high-density server rooms, leveraging evaporative principles to reduce energy consumption and PUE (Power Usage Effectiveness).
Quality Certifications & Standards Compliance
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 ensuring consistent manufacturing quality and process control.
- ISO 14001:2015 — Environmental Management System certification demonstrating commitment to sustainable manufacturing practices.
- EN 10204 3.1 — Material test certificates provided with each shipment, confirming compliance with specified chemical and mechanical properties.
- ASTM A213 / ASME SA-213 — Conformity with international standards for seamless and welded austenitic stainless steel tubing.
- EN 10216-5 — Compliance with European standards for welded austenitic stainless steel tubes.
- CE Marking — Product conformity with European health, safety, and environmental protection standards.
- Mill Test Reports (MTR) — Full traceability documentation available for each production lot.
Unique Selling Points
- Research-Driven Optimization: Product design informed by published research on the effects of cooling wind speed and spray water volume on water distribution uniformity, resulting in superior thermal-hydraulic performance.
- Customizable Geometry: Flexible coil pitch, diameter, and length configurations tailored to specific system requirements, enabling optimal integration into diverse cooling architectures.
- Exceptional Corrosion Resistance: High-grade austenitic stainless steel construction ensures decades of service life in aggressive, wet, and chemically challenging environments without degradation of performance.
- Hygienic Surface Quality: Bright annealed (BA) finish option provides a smooth, non-porous surface ideal for food-grade and pharmaceutical applications, facilitating easy cleaning and preventing bacterial colonization.
- Energy Efficiency: Optimized coil geometry maximizes evaporative heat transfer surface area, reducing system energy consumption and operating costs over the product lifecycle.
- Full Traceability & Certification: Comprehensive documentation and international certifications provide assurance of quality, safety, and regulatory compliance for global deployment.
Note: All specifications are subject to change based on material availability and customer-specific requirements. For detailed engineering consultation, custom design services, or sample evaluation, contact Wenzhou Jixing Metal Materials Co., Ltd directly.