Stainless Steel Coil Tube (Coiltube) – Wenzhou Jixing Metal Materials Co., Ltd
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) is a continuously wound tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd, a leading supplier in the Chinese metal materials sector. Coil tubes are produced in long, uninterrupted lengths wound onto reels or coils, distinguishing them from straight-cut pipe sections. This continuous form factor offers significant advantages in downstream processing, including reduced welding joints, minimized material waste, and enhanced production efficiency in automated forming lines.
Coil tubes are widely employed in heat exchange systems, fluid conveyance networks, automotive exhaust components, and HVAC (Heating, Ventilation, and Air Conditioning) applications—particularly in fan coil unit assemblies where precise dimensional tolerances and thermal performance are critical. The integration of coil tube technology with advanced fan speed control systems, as studied in research on silicon-controlled (thyristor-based) fan coil unit speed regulation, demonstrates the product's role in energy-efficient thermal management solutions.
2. Material & Properties
Stainless steel coil tubes are fabricated from austenitic, ferritic, and duplex stainless steel grades, selected based on the specific service environment and performance requirements.
- Austenitic Grades (e.g., AISI 304 / 304L, AISI 316 / 316L): Provide excellent corrosion resistance, weldability, and formability. The addition of molybdenum in 316/316L grades enhances pitting and crevice corrosion resistance, making them suitable for chemical processing and marine environments.
- Ferritic Grades (e.g., AISI 430, AISI 439): Offer good resistance to stress corrosion cracking and moderate corrosion resistance at a lower cost, commonly used in automotive and architectural applications.
- Duplex Grades (e.g., 2205): Combine the strengths of austenitic and ferritic microstructures, delivering high yield strength, superior chloride pitting resistance, and reduced risk of stress corrosion cracking.
Key Mechanical and Physical Properties
- Excellent resistance to oxidation and corrosion in aggressive chemical environments
- High strength-to-weight ratio, enabling lightweight system design
- Superior hygienic properties with smooth inner and outer surface finishes
- Good thermal conductivity for efficient heat exchange applications
- Outstanding fatigue resistance and long service life under cyclic loading
3. Technical Specifications
| Parameter | Specification / Range |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Material Grades | AISI 304, 304L, 316, 316L, 321, 310S, 430, 2205, 316Ti |
| Outer Diameter (OD) | 3.0 mm – 114.3 mm (custom sizes available upon request) |
| Wall Thickness | 0.3 mm – 6.0 mm |
| Coil Length | Continuous; typically 50 m – 300 m per coil (configurable) |
| Surface Finish | No. 1 (Hot Rolled), 2B (Cold Rolled & Annealed), BA (Bright Annealed), No. 4 (Brushed), HL (Hairline), Mirror (8K) |
| Tolerance (OD) | ±0.1 mm (standard); ±0.05 mm (precision grade) |
| Tolerance (Wall Thickness) | ±10% of nominal |
| Standards Compliance | ASTM A213, ASTM A269, ASME SA-213, GB/T 12771, EN 10217-7, ISO 3506 |
| End Condition | Plain end, beveled end, or custom-formatted per customer specification |
| Coil Packing | Wooden pallet with moisture-proof wrapping; protective inner liner available |
| Minimum Order Quantity (MOQ) | 1 ton (negotiable based on grade and dimensions) |
4. Manufacturing Process
The production of stainless steel coil tubes at Wenzhou Jixing Metal Materials follows a rigorous, multi-stage process ensuring dimensional accuracy, metallurgical integrity, and surface quality:
- Slit and Coil Formation: Stainless steel strip (coil) is slit to the required width and fed into the tube-forming line. The strip is cold-formed around a mandrel to produce the initial tubular shape.
- Welding (for Welded Coil Tubes): The formed strip is welded using Automatic Submerged Arc Welding (ASAW), Longitudinal Argon Arc Welding (LAW), or TIG (Tungsten Inert Gas) welding, depending on the grade and wall thickness. Laser welding is employed for high-precision, high-integrity applications.
- Heat Treatment (Annealing): Post-weld annealing is conducted in a continuous bright annealing furnace under a protective hydrogen-nitrogen atmosphere to relieve residual stresses, restore ductility, and achieve the desired grain structure. Bright annealing preserves surface finish without the need for subsequent pickling.
- Pickling and Passivation: For non-bright annealed products, an acid pickling process removes surface oxide scale, followed by a passivation treatment to restore the chromium oxide passive layer, ensuring optimal corrosion resistance.
- Surface Finishing: Depending on the required finish grade, additional processing such as polishing, brushing, or mirror finishing may be applied.
- Dimensional Inspection and Quality Control: Each coil undergoes rigorous inspection including ultrasonic testing (UT), eddy current testing (ECT), dimensional measurement, and visual examination to ensure compliance with specified tolerances and quality standards.
- Coiling and Packaging: The finished tube is wound onto a coil reel, secured, and packaged with moisture-barrier materials to prevent surface contamination during storage and transportation.
5. Applications
Stainless steel coil tubes find extensive use across diverse industrial sectors:
- HVAC Systems: Used in fan coil units, air handling units, and heat exchangers where reliable fluid transport and thermal efficiency are paramount. Integration with thyristor-controlled fan speed regulation systems enables precise energy management.
- Automotive Industry: Exhaust system components, fuel lines, brake lines, and turbocharger manifolds requiring high-temperature resistance and durability.
- Chemical Processing: Conveyance of aggressive chemicals, acids, and solvents in processing plants and refineries.
- Food and Beverage Industry: Hygienic-grade tubing for dairy, brewing, and pharmaceutical processing lines requiring cleanability and corrosion resistance.
- Oil and Gas: Downhole tubing, flow lines, and subsea applications where chloride resistance and mechanical strength are essential.
- Construction and Architecture: Structural tubing, handrails, and decorative elements leveraging the aesthetic and durability properties of stainless steel.
- Medical Equipment: Precision tubing for surgical instruments, dialysis machines, and laboratory apparatus.
- Energy Sector: Solar thermal collectors, geothermal heat exchangers, and nuclear-grade applications.
6. Quality Certifications and Standards
Wenzhou Jixing Metal Materials Co., Ltd maintains comprehensive quality management systems and certifications to assure product excellence:
- ISO 9001:2015 – Quality Management System Certification
- ISO 14001:2015 – Environmental Management System Certification
- ISO 45001:2018 – Occupational Health and Safety Management System
- EN 10204 3.1 – Material Test Certificates (MTC) available upon request
- Mill Test Reports (MTR): Full traceability documentation including chemical composition analysis, mechanical test results, and heat treatment records provided with every shipment
- Third-Party Inspection: Independent verification available through SGS, BV, or TÜV upon customer request
7. Unique Selling Points
- Continuous Length Advantage: Coil format eliminates intermediate joints, reducing leak points and improving system integrity in fluid and gas applications.
- Wide Grade Selection: Extensive inventory of austenitic, ferritic, and duplex stainless steel grades to meet diverse application requirements.
- Customization Capability: Flexible manufacturing to accommodate non-standard dimensions, surface finishes, and coil configurations.
- Superior Surface Quality: Bright annealing and precision finishing processes ensure consistent, high-quality surface finishes suitable for hygienic and aesthetic applications.
- Full Traceability: Complete documentation from raw material to finished product, ensuring compliance with international standards and regulatory requirements.
- Cost Efficiency: The coil format reduces material waste and processing time in downstream fabrication, delivering total cost of ownership advantages over straight pipe alternatives.
8. Ordering and Technical Support
Customers are encouraged to provide detailed specifications including required grade, dimensions, surface finish, quantity, and intended application. Wenzhou Jixing Metal Materials Co., Ltd offers comprehensive pre-sales technical consultation, sample provision, and post-sales support to ensure optimal product selection and application performance. Custom engineering solutions are available for specialized projects requiring tailored stainless steel coil tube configurations.