Stainless Steel Coil Tube (Coiltube) — Product Technical Specification
Product Overview
The Stainless Steel Coil Tube (hereinafter referred to as "Coiltube") is a precision-engineered continuous tubing product supplied in a coiled configuration, manufactured by Wenzhou Jixing Metal Materials Co., Ltd. (Product No. 1002). This product is designed for integration into coil tube fan systems and heat exchange applications, where energy efficiency, noise reduction, and thermal performance are critical design parameters. The coiltube is formed from high-grade austenitic stainless steel and wound into a continuous helical coil, offering superior flexibility in installation, extended service life, and resistance to corrosion in aggressive environments.
This product has been developed with reference to advanced research on Coil Tube Fan Design Methodology and Energy-Saving Noise Reduction Technologies, incorporating insights from aerodynamic optimization, thermal-hydraulic analysis, and vibration control to deliver an integrated solution for HVAC, industrial process heating/cooling, and refrigeration systems.
Material & Properties
The Coiltube is fabricated from austenitic stainless steel alloys conforming to international standards, ensuring mechanical strength, corrosion resistance, and thermal conductivity suited for demanding industrial environments.
- Primary Grades: AISI 304 (UNS S30400), AISI 316 (UNS S31600), AISI 316L (UNS S31603), AISI 321 (UNS S32100)
- Corrosion Resistance: Excellent resistance to pitting, crevice corrosion, and intergranular corrosion; particularly suited for chloride-containing environments (316/316L grades)
- Thermal Conductivity: 14.2–16.3 W/(m·K) at 25°C (typical for austenitic grades), ensuring efficient heat transfer in coil fan and heat exchanger applications
- Operating Temperature Range: −196°C to +870°C (grade-dependent), with sustained high-temperature stability for 321 (stabilized with titanium)
- Mechanical Properties: Tensile strength ≥ 515 MPa (304), yield strength ≥ 205 MPa; elongation ≥ 40% for cold-worked conditions
- Surface Finish: 2B (cold-rolled and annealed), BA (Bright Annealed), or custom polished finishes (Ra ≤ 0.4 μm available upon request)
- Magnetic Properties: Non-magnetic in annealed condition (≤ 3 Gauss), ensuring compatibility with electromagnetic equipment
Specifications
| Parameter | Specification / Range | Standard Reference |
|---|---|---|
| Product Designation | Stainless Steel Coil Tube (Coiltube) | Internal Product No. 1002 |
| Outer Diameter (OD) | Φ3.0 mm – Φ50.8 mm (custom sizes available) | ASTM A213 / ASTM A269 |
| Wall Thickness (WT) | 0.3 mm – 3.0 mm | ASTM A269 Table 11 |
| Coil Inner Diameter (CID) | Φ50 mm – Φ300 mm | Custom per application |
| Coil Length per Spool | 50 m – 500 m (continuous) | — |
| Material Grades | 304, 316, 316L, 321, 310S, 904L (special order) | ASTM A213 / EN 10216-5 / GB/T 14976 |
| Tolerance (OD) | ±0.05 mm (precision grade) | ASTM A269 |
| Tolerance (WT) | ±10% | ASTM A269 |
| Surface Finish | 2B / BA / No. 4 Brushed / Mirror (custom) | ASTM A480 |
| End Condition | Plain / Beveled / Threaded / Flanged (custom) | ASME B1.20.1 |
| Heat Treatment | Solution annealed (1050–1150°C) + water quench | ASTM A213 |
| Coating / Passivation | Acid pickling and passivation (standard); PTFE coating available | ASTM A967 |
| Packaging | Wooden reel / steel drum with moisture-proof wrapping | ISO 11607 |
Manufacturing Process
The production of the Stainless Steel Coil Tube follows a rigorous multi-stage manufacturing workflow designed to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Procurement: Ingot or strip sourcing from certified mills with full chemical composition analysis (PCM — Product Certificate per Mill) and mechanical test reports.
- Hot Rolling & Annealing: Billet or strip is hot-rolled to approximate dimensions, followed by controlled annealing to relieve internal stresses and refine grain structure.
- Cold Drawing / Cold Rolling: The tube blank undergoes precision cold drawing through tungsten carbide (WC) or hardened steel dies to achieve final OD and WT within tight tolerances.
- Intermediate Annealing: Periodic solution annealing (1050–1150°C) with rapid water quenching restores ductility between cold working passes, preventing cracking and ensuring uniform microstructure.
- Coil Winding (Coiling): The continuous drawn tube is wound onto a precision mandrel using CNC-controlled coiling equipment to maintain consistent pitch, tension, and concentricity — critical for downstream coil fan assembly and aerodynamic performance.
- Pickling & Passivation: The coiled tube is subjected to acid pickling (HNO₃ + HF or HNO₃ + HCl blend) to remove mill scale and oxidation, followed by passivation to form a protective chromium oxide film (≥ 200 mV potential per ASTM A967).
- Quality Inspection: Non-destructive testing (NDT) including eddy current inspection, hydrostatic pressure testing (1.5× working pressure), dimensional gauging, and spectrographic composition verification.
- Packaging & Dispatch: Final coils are wrapped in moisture-barrier film, secured on wooden reels or steel drums, and labeled with traceability documentation.
Applications
The Stainless Steel Coil Tube is engineered for a wide range of industrial and commercial applications:
- Coil Tube Fan Systems (CTF): Primary application in centrifugal and axial fan assemblies where the coil tube serves as the blade or air-carrying structure; optimized for energy efficiency and noise reduction as per advanced CTF design methodologies.
- Heat Exchangers: Double-pipe heat exchangers, spiral heat exchangers, and shell-and-coil configurations in chemical, petrochemical, and power generation industries.
- HVAC Systems: Chilled water coils, condenser coils, and evaporator assemblies in commercial and industrial air conditioning units.
- Refrigeration & Cryogenics: Low-temperature refrigeration circuits, ammonia absorption chillers, and cryogenic process piping requiring ductility at sub-zero temperatures.
- Food & Pharmaceutical Processing: Sanitary-grade heat transfer coils in pasteurization, sterilization, and CIP (Clean-in-Place) systems where corrosion resistance and hygienic surfaces are paramount.
- Power Generation: Steam generator tubes, feedwater heaters, and condenser coils in thermal power plants and nuclear facilities (321/310S grades).
- Marine & Offshore: Seawater cooling coils and ballast water heat exchangers leveraging 316L's superior chloride resistance.
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring full traceability and compliance with international standards:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001:2015 — Environmental Management System
- ISO 45001:2018 — Occupational Health and Safety Management
- EN 10204 3.1 — Material Test Reports (MTR) with third-party inspection
- CE Marking — Compliance with European directives (PED 2014/68/EU where applicable)
- API 5L / API 5CT — Available for oil & gas applications (special order)
- NACE MR0175 / ISO 15156 — Resistance to sulfide stress cracking (for sour service applications)
- GB/T 14976, GB/T 13296 — Chinese national standards for seamless stainless steel tubes
- ASME B31.3 / B31.5 — Process piping and hydraulic piping code compliance
Unique Selling Points
1. Research-Driven Design Integration: The Coiltube product line is informed by advanced research in coil tube fan design methodology, energy-saving optimization, and noise reduction engineering — enabling customers to achieve superior aerodynamic efficiency and lower operational noise levels in fan and heat exchange systems.
2. Continuous Length Advantage: Supplied as a continuous coil (up to 500 m per spool), eliminating weld joints and reducing potential leak points, improving system reliability and lowering maintenance costs.
3. Precision Dimensional Control: Tight tolerances (±0.05 mm OD) ensure seamless integration into automated coil winding and assembly processes, reducing scrap rates and improving manufacturing yield.
4. Grade Flexibility: Availability in multiple stainless steel grades (304, 316, 316L, 321, 310S, 904L) allows customers to select the optimal alloy for specific corrosion, temperature, and mechanical requirements.
5. Full Traceability: Each coil is accompanied by a complete Product Certificate per Mill (PCoM) including chemical analysis, mechanical test data, and heat number traceability, ensuring regulatory compliance and quality assurance.
6. Customization Capability: Custom coil diameters, lengths, surface finishes, end treatments, and special alloy compositions are available upon request, supporting project-specific engineering requirements.
Technical Notes
Customers are advised to consult the manufacturer for grade-specific mechanical property data, corrosion resistance recommendations, and application-specific design guidance. For coil tube fan integration, aerodynamic performance optimization requires consideration of coil pitch, tube cross-section geometry, and rotational speed parameters. Wenzhou Jixing Metal Materials Co., Ltd. provides technical support and application engineering services to assist in system-level design optimization.