Stainless Steel Coil Tube (Coil Pipe) — Series-Connected Pipeline System
Product Overview
The Stainless Steel Coil Tube (Coil Pipe) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered continuous tubular product designed for demanding industrial applications where dynamic loading, cyclic stress, and resonance phenomena are critical design considerations. This coil tube product is specifically engineered for series-connected pipeline systems (串联盘管道) that operate under continuous conveyor wire rope traction (钢丝绳牵引), where both traction speed and acceleration undergo periodic variation (周期变化). The product integrates advanced metallurgical composition with optimized geometric parameters to ensure structural integrity and fatigue resistance under complex vibrational environments.
Unlike conventional straight-length stainless steel tubing, the coil tube form factor enables continuous-length supply without weld joints, significantly reducing potential failure points in high-cycle applications. The coil configuration also facilitates efficient storage, transportation, and on-site deployment in continuous processing lines.
Material & Properties
The coil tube is fabricated from austenitic stainless steel grades compliant with international standards, offering superior resistance to corrosion, mechanical fatigue, and thermal cycling. Key material properties include:
- Grade Options: AISI 304 (UNS S30400), AISI 316L (UNS S31603), AISI 321 (UNS S32100), and custom alloy compositions
- Chromium Content: 18.0–21.0% (minimum), providing robust passive film formation and oxidation resistance
- Nickel Content: 8.0–11.0%, ensuring stable austenitic microstructure and ductility
- Molybdenum Content: 2.0–3.0% (in 316L grade), enhancing pitting and crevice corrosion resistance
- Tensile Strength: ≥ 520 MPa (as-supplied, annealed condition)
- Yield Strength: ≥ 205 MPa (0.2% offset)
- Elongation: ≥ 40% (at fracture)
- Hardness: ≤ 217 HB (annealed condition), ensuring formability for coil winding operations
- Resonance Frequency Optimization: Material damping capacity tailored to mitigate harmonic amplification under periodic wire rope traction loads
Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 6.0 mm – 168.3 mm (custom sizes available) | ASTM A213 / A269 |
| Wall Thickness | 0.5 mm – 12.0 mm | ASTM A213 / A269 |
| Coil Inner Diameter (CID) | 300 mm – 1200 mm | Company specification |
| Coil Outer Diameter (COD) | 600 mm – 2400 mm | Company specification |
| Tube Length per Coil | 20 m – 500 m (continuous, seam-free) | Company specification |
| Surface Finish | Mirror polished (Ra ≤ 0.4 μm), sanitary (Ra ≤ 0.8 μm), or industrial (Ra ≤ 1.6 μm) | ASTM A269 / GB/T 12771 |
| Dimensional Tolerance (OD) | ±0.05 mm (precision grade) / ±0.10 mm (standard grade) | ASTM A213 |
| Dimensional Tolerance (Wall) | ±10% of nominal | ASTM A269 |
| Temperature Range | −196 °C to +870 °C (continuous service) | ASME Section VIII |
| Pressure Rating | Up to 40 MPa (design-dependent) | ASME BPV Code |
| Minimum Bend Radius | 3× OD (cold bending) | Company specification |
| Resonance Load Cycle Resistance | ≥ 10⁷ cycles at design stress amplitude | Internal fatigue testing protocol |
Manufacturing Process
The coil tube production process at Wenzhou Jixing Metal Materials Co., Ltd. follows a multi-stage precision manufacturing sequence designed to ensure dimensional accuracy, microstructural homogeneity, and mechanical performance:
- Slit Coil Preparation: High-purity stainless steel strip is slitted from hot-rolled coil (HRC) or cold-rolled coil (CRC) to precise width specifications. Incoming material undergoes spectrographic verification for chemical composition compliance.
- Forming & Welding (for welded coil tube): The strip is formed into tubular geometry via roll-forming or mandrel-die forming. For welded variants, TIG (Tungsten Inert Gas) welding is employed with argon shielding, followed by internal wire brushing to achieve uniform weld bead quality.
- Induction Annealing: Continuous induction heating achieves full solution annealing (1050–1150 °C), followed by controlled cooling to restore full austenitic structure and eliminate residual stresses from forming operations.
- Pickling & Passivation: The annealed coil tube undergoes acid pickling (nitric/hydrofluoric acid blend) to remove scale, followed by passivation treatment to establish a stable chromium oxide passive film.
- Precision Sizing: Cold drawing through calibrated dies achieves final dimensional tolerances while inducing beneficial work-hardening for enhanced fatigue resistance.
- Coil Winding & Packaging: The finished tube is wound onto precision-mandrel coils with controlled tension to prevent deformation. Each coil is wrapped in protective film and secured for transport.
Applications
The stainless steel coil tube is engineered for a diverse range of industrial applications, with particular emphasis on systems subject to dynamic cyclic loading:
- Continuous Conveyor Systems: Series-connected pipeline arrays in mining, cement, and bulk material handling operations where wire rope traction induces periodic speed and acceleration variations
- Heat Exchanger Coils: Spiral wound heat exchangers in chemical processing, power generation, and HVAC systems
- Pharmaceutical & Food Processing: Sanitary-grade tubing for CIP (Clean-in-Place) compatible fluid transfer systems
- Petrochemical Pipelines: Corrosion-resistant coil tubing for refinery heat tracing, steam supply, and process fluid transport
- Automotive & Aerospace: Precision tubing for fuel lines, hydraulic circuits, and exhaust systems
- Resonance-Critical Infrastructure: Pipeline systems where vibration analysis (共振分析) demonstrates the need for fatigue-resistant materials under cyclic operational loads
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management systems and product certifications ensuring global market compliance:
- ISO 9001:2015 — Quality Management System certification for manufacturing operations
- ISO 14001:2015 — Environmental Management System certification
- EN 10204 — Type 3.1 mill test certificates provided with each shipment
- ASTM / ASME — Material and fabrication compliance with applicable American standards
- GB/T 12771 — Chinese national standard for stainless steel seamless and welded tubes
- DIN / EN — European standard compliance for applicable grades
- Third-Party Inspection: Available upon request (SGS, BV, TUV, Lloyd's)
Unique Selling Points
Resonance-Optimized Design: Leveraging advanced vibration analysis principles (共振分析) for series-connected coil pipelines under cyclically varying wire rope traction conditions, the product is engineered with optimized wall thickness-to-diameter ratios and material damping characteristics that minimize harmonic amplification and extend service life under dynamic loading.
Continuous-Length Integrity: The coil tube format eliminates intermediate weld joints found in straight-length pipe assemblies, providing superior fatigue performance and reduced maintenance requirements in high-cycle applications.
Precision Dimensional Control: Cold-drawing processes achieve tolerances as tight as ±0.05 mm on outer diameter, ensuring interchangeability and reliable fit in automated assembly systems.
Customization Capability: Full customization of alloy grade, dimensions, surface finish, coil geometry, and post-processing (heat treatment, coating) to meet specific application requirements.