High-Efficiency Energy-Saving Inner Threaded Stainless Steel Coil Tube (Coil Tube)
Product Overview
The High-Efficiency Energy-Saving Inner Threaded Stainless Steel Coil Tube (Product No. 1273) is a precision-engineered heat exchange component manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product represents a significant advancement in thermal transfer technology, combining the superior corrosion resistance and mechanical strength of stainless steel with an innovative internal helical thread (Inner Threaded Structure) design that dramatically enhances heat transfer efficiency while reducing energy consumption.
The coil tube is wound into a continuous helical configuration, optimizing surface-area-to-volume ratios for maximum thermal exchange in compact spaces. The internal threading creates turbulence in the fluid stream, breaking up the laminar boundary layer and significantly increasing the heat transfer coefficient (Heat Transfer Coefficient) compared to smooth-wall tubes. This technology is particularly suited for applications demanding high thermal performance within constrained installation footprints.
Material and Properties
Base Material
The coil tube is fabricated from high-grade austenitic stainless steel, primarily SUS304 (UNS S30400) or SUS316L (UNS S31603), selected for their exceptional resistance to general corrosion, pitting, and stress corrosion cracking (Stress Corrosion Cracking, SCC) in diverse operating environments.
Key Material Properties
- Corrosion Resistance: Superior resistance to atmospheric, chemical, and marine environments due to the formation of a stable chromium oxide (Cr₂O₃) passive film.
- Thermal Conductivity: Approximately 16.3 W/(m·K) for SUS304 and 14.6 W/(m·K) for SUS316L, providing efficient thermal conduction through the tube wall.
- Mechanical Strength: Yield strength of ≥205 MPa (SUS304) and ≥170 MPa (SUS316L), ensuring structural integrity under high-pressure operating conditions.
- Temperature Range: Operational capability from cryogenic temperatures (−196°C) to elevated temperatures (up to 870°C for SUS304 and 815°C for SUS316L).
- Hygienic Surface: Low surface roughness (Ra ≤ 0.4 μm) suitable for food-grade and pharmaceutical applications.
Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Product Category | Coil Tube (盘管) | — |
| Product No. | 1273 | — |
| Material Grade | SUS304 / SUS316L / SUS321 / SUS310S | ASTM A269 / ASTM A312 |
| Outer Diameter (OD) | Φ6.0 mm – Φ32.0 mm | Customizable |
| Wall Thickness | 0.3 mm – 1.5 mm | — |
| Inner Thread Pitch | 0.5 mm – 2.0 mm (adjustable) | Proprietary design |
| Coil Winding Diameter | Φ100 mm – Φ600 mm | Application-dependent |
| Maximum Operating Pressure | ≤ 4.0 MPa | ASME B31.3 |
| Heat Transfer Enhancement Factor | 1.5 – 2.8× (vs. smooth tube) | Experimental validation |
| Surface Treatment | Pickling & Passivation / Electropolishing | ASTM A967 |
| End Forming | Plain / Flanged / Threaded / Brazed | Customer specification |
| Length | 1 m – 50 m (continuous coil) | Customizable |
| Applicable Media | Water, refrigerants, steam, food-grade liquids, chemical solutions | — |
Manufacturing Process
The production of the High-Efficiency Energy-Saving Inner Threaded Stainless Steel Coil Tube involves a multi-stage precision manufacturing sequence designed to ensure dimensional accuracy, surface integrity, and optimal thermal performance:
- Raw Material Selection and Inspection: High-purity stainless steel seamless capillary tubes are sourced from certified mills and subjected to spectroscopic analysis (Spectroscopic Composition Analysis) to verify chemical composition within specified limits.
- Inner Threading (Cross-Hole Threading): A precision cross-hole threading process (Cross-Hole Threading Process) is applied to the internal surface of the tube. This creates helical ribs (Helical Ribs) that induce secondary flow (Secondary Flow) and increase turbulence, thereby enhancing the convective heat transfer coefficient. The threading is performed using specialized diamond tooling on CNC-controlled threading machines to maintain consistent thread geometry.
- Coil Winding: The threaded tube is wound into a precise helical coil using computer-controlled winding equipment. The winding process ensures uniform pitch, constant coil diameter, and minimal mechanical stress on the tube wall.
- Welding and Brazing: End joints and connection points are formed using orbital TIG welding (Tungsten Inert Gas Welding) or high-purity silver brazing (Silver Brazing), ensuring leak-tight seals and minimal metallurgical distortion.
- Pickling and Passivation: The completed coil tube undergoes chemical pickling (Chemical Pickling) and passivation (Passivation Treatment) to remove oxide scale, contaminants, and carbon residue, restoring the full corrosion resistance of the passive chromium oxide layer.
- Hydrostatic Pressure Testing: Each coil tube is subjected to hydrostatic pressure testing (Hydrostatic Pressure Testing) at 1.5× the maximum working pressure to verify structural integrity and weld quality.
- Final Inspection and Packaging: Products undergo dimensional verification, visual inspection, and surface finish measurement before being packaged with protective end caps and moisture-absorbent materials for shipment.
Applications
The High-Efficiency Energy-Saving Inner Threaded Stainless Steel Coil Tube finds extensive application across multiple industries where compact, high-performance heat exchange is critical:
- Refrigeration and Air Conditioning (HVAC): Evaporator and condenser coils in commercial refrigeration units, heat pumps, and air conditioning systems. The inner threading reduces refrigerant flow resistance while increasing heat transfer, improving Coefficient of Performance (COP).
- Automotive Industry: Compact heat exchangers for electric vehicle (Electric Vehicle, EV) battery thermal management systems, where space constraints and thermal efficiency are paramount.
- Food and Beverage Processing: Pasteurization systems, cooling coils, and heat recovery units where hygienic-grade stainless steel surfaces are required and energy efficiency reduces operational costs.
- Pharmaceutical Manufacturing: Clean-in-Place (Clean-in-Place, CIP) compatible heat exchangers for sterilization processes and process fluid temperature control.
- Power Generation: Waste heat recovery systems and economizer coils in industrial boilers and combined heat and power (Combined Heat and Power, CHP) installations.
- Chemical Processing: Reactor cooling systems and process heat exchangers handling corrosive fluids where stainless steel's chemical inertness is essential.
Quality Certifications and Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring that every coil tube product meets or exceeds international standards:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and continuous improvement processes.
- ISO 14001:2015 — Environmental Management System certification demonstrating commitment to sustainable manufacturing practices.
- CE Marking (European Conformity) — Compliance with applicable European Directives for products entering the European Economic Area.
- ASTM / ASME Standards — Material and pressure vessel compliance with ASTM A269, ASTM A312, and ASME B31.3 for process piping.
- EN 10217 / EN 10216 — European standards for heat exchanger tubing and boiler tubes.
- JIS G3445 / JIS G3459 — Japanese Industrial Standards for seamless stainless steel tubing.
- NSF/ANSI 61 — Drinking water system component certification (where applicable).
- 3-A Sanitary Standards — Food-grade equipment certification for dairy and beverage industry applications.
Unique Selling Points
1. Superior Heat Transfer Performance: The proprietary inner threading technology achieves a heat transfer enhancement factor of 1.5–2.8× compared to conventional smooth-wall tubes, enabling significant reductions in equipment footprint and energy consumption.
2. Energy Savings: By increasing thermal efficiency, the coil tube reduces compressor work in refrigeration systems and lowers fuel consumption in heating applications, delivering measurable operational cost reductions and a shorter return on investment (Return on Investment, ROI).
3. Enhanced Fouling Resistance: The internal turbulence generated by the helical threads promotes self-cleaning action, reducing fouling (Fouling Deposition) accumulation and extending maintenance intervals.
4. Versatile Material Options: Availability in multiple stainless steel grades (SUS304, SUS316L, SUS321, SUS310S) allows selection tailored to specific corrosion environments and temperature requirements. 5. Precision Manufacturing: CNC-controlled threading and winding processes ensure dimensional consistency, repeatability, and optimal thermal performance across every production batch. 6. Comprehensive After-Sales Support: Wenzhou Jixing provides technical consultation, custom design services, and full traceability documentation for each product shipment.
This product exemplifies the convergence of advanced metallurgy, precision manufacturing, and thermal engineering — delivering a solution that meets the evolving demands of energy-efficient, high-performance industrial heat exchange systems.