Stainless Steel Coil Tube (盘管) — Technical Specification
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.
Product Category: Literature Study / Technical Reference
Reference No.: 1271
Product Designation: Stainless Steel Coil Tube (盘管 Coiltube)
1. Product Overview
The Stainless Steel Coil Tube is a continuously formed tubular product manufactured through advanced coil winding and forming technology. Unlike conventional straight seamless or welded tubes, coil tubes are produced in long, continuous lengths wound into coils, offering significant advantages in material utilization, production efficiency, and downstream processing flexibility. This product represents the integration of domestic coil tube technology and equipment development methodologies, reflecting advancements in precision forming, seamless welding, and automated coil winding systems.
The coil tube is engineered for applications requiring continuous-length stainless steel tubing with minimal joints, superior mechanical integrity, and resistance to corrosion in demanding industrial environments. The technology encompasses both copper coil tube development principles and their adaptation to stainless steel alloy systems, leveraging lessons learned from domestic R&D in coil forming equipment, die systems, and quality control methodologies.
2. Material & Properties
2.1 Alloy Grades
- Austenitic Stainless Steels: AISI 304 (UNS S30400), AISI 304L (UNS S30403), AISI 316 (UNS S31600), AISI 316L (UNS S31603)
- Duplex Stainless Steels: AISI 2205 (UNS S32205), Super Duplex 2507 (UNS S32750)
- Custom Alloy Systems: Available upon specification for specialized corrosion or temperature environments
2.2 Mechanical Properties (Typical — Annealed Condition)
| Property | AISI 304 | AISI 316L | AISI 2205 |
|---|---|---|---|
| Tensile Strength (UTS) | ≥ 515 MPa | ≥ 485 MPa | ≥ 550 MPa |
| Yield Strength (0.2% Offset) | ≥ 205 MPa | ≥ 170 MPa | ≥ 450 MPa |
| Elongation (% at Break) | ≥ 40% | ≥ 40% | ≥ 25% |
| Density (g/cm³) | 8.00 | 8.00 | 7.85 |
| Thermal Conductivity (W/m·K at 20°C) | 16.3 | 14.6 | 15.1 |
2.3 Corrosion Resistance
- Excellent resistance to atmospheric corrosion, freshwater, and dilute organic acids
- Superior pitting and crevice corrosion resistance (particularly 316L and duplex grades)
- High-temperature oxidation resistance up to 870°C (304) and 925°C (2205)
- Resistance to stress corrosion cracking (SCC) in chloride environments (low-carbon grades)
3. Specifications
| Parameter | Specification / Range | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | Φ6.0 mm – Φ50.8 mm | ASTM A213 / EN 10216-5 |
| Wall Thickness (WT) | 0.5 mm – 3.0 mm | ASTM A213 / EN 10216-5 |
| Coil Length per Spool | 100 m – 1,000 m (continuous) | Manufacturer Specification |
| Coil Inner Diameter (ID) | Φ200 mm – Φ600 mm | Customer Requirement |
| OD Tolerance | ±0.05 mm (precision grade) / ±0.10 mm (standard grade) | ASTM A213 |
| Wall Thickness Tolerance | ±10% (standard) / ±5% (precision) | EN 10216-5 |
| Surface Finish | Mirror (Ra ≤ 0.1 μm), Brushed (Ra ≤ 0.8 μm), Matte (Ra ≤ 1.6 μm) | ASTM A403 |
| Weld Seam Quality | 100% penetration weld; ultrasonic tested | ASTM A213 |
| Heat Treatment | Solution Annealed (1050°C – 1150°C) + Water Quench | ASTM A213 |
| Maximum Operating Temperature | Up to 870°C (304) / 925°C (2205) | ASM Code Section VIII |
| Minimum Operating Temperature | Down to −196°C (LN₂ service, austenitic grades) | ASTM A213 |
4. Manufacturing Process
4.1 Process Flow
- Coil Slitting & Leveling: Cold-rolled stainless steel strip is slit to precise width and leveled to eliminate coil set, ensuring uniform feed into the forming station.
- Tube Forming (Roll Forming): Multi-roll progressive forming stations shape the flat strip into a circular tube profile. Die sets are precision-machined from hardened tool steel with tolerance control to ±0.01 mm.
- Seam Welding: High-frequency induction welding (HF-W) or laser welding (LW) is applied to form the longitudinal weld seam. Weld parameters are dynamically controlled based on material grade, thickness, and forming speed.
- In-Line Annealing: Post-weld annealing in a protective atmosphere (nitrogen or argon) relieves residual stresses, restores ductility, and stabilizes the microstructure. Temperature is maintained at 1050°C–1150°C for austenitic grades.
- Pickling & Passivation: Continuous pickling in a mixed acid bath (HNO₃ + HF) removes heat scale and oxidation products. Passivation treatment enriches the chromium oxide surface film for enhanced corrosion resistance.
- Precision Sizing: Cold-drawn or calibrated through precision dies to achieve final dimensional tolerances and surface finish specifications.
- Coil Winding: The continuous tube is wound into coils of specified diameter using an automated winding system with controlled tension to prevent deformation or kinking.
- Quality Inspection: In-line ultrasonic testing (UT), eddy current testing (ECT), and hydrostatic pressure testing ensure 100% weld integrity and material soundness.
4.2 Key Technological Advantages
- Continuous Production: Eliminates butt welds, reducing potential failure points and improving structural integrity.
- High Material Utilization: Coil processing achieves >95% material yield compared to cut-length processing.
- Automated Forming: CNC-controlled roll forming stations ensure dimensional consistency across production runs exceeding 10,000 meters.
- Integrated Quality Control: Real-time monitoring of weld quality, dimensional accuracy, and surface integrity throughout the production line.
5. Applications
5.1 Primary Application Domains
| Industry | Application | Key Requirement |
|---|---|---|
| Automotive | Exhaust system tubing, turbocharger manifolds, fuel lines | High-temperature resistance, vibration fatigue |
| Petrochemical | Heat exchanger tubes, process piping, reactor internals | Corrosion resistance, pressure containment |
| Food & Beverage | Processing lines, CIP/SIP systems, hygienic piping | Surface finish, sanitary compliance |
| Pharmaceutical | Process equipment, sterilization systems, fluid transfer | BPE surface finish, GMP compliance |
| Energy | Solar thermal collectors, geothermal heat exchangers | Thermal cycling resistance, UV stability |
| Medical | Endoscopy instruments, implant-grade tubing, surgical equipment | Bio-compatibility, ultra-fine tolerances |
| Construction | Structural bracing, decorative cladding, railing systems | Mechanical strength, aesthetic finish |
| Electronics | Heat dissipation channels, precision fluidic systems | Dimensional accuracy, thermal management |
5.2 Coil Tube Advantages Over Straight Tube
- Reduces inventory holding costs through continuous-length supply
- Minimizes downstream cutting waste in fabrication operations
- Enables roll-to-roll processing for high-volume manufacturing
- Facilitates automated forming, bending, and welding operations
6. Quality Certifications & Standards Compliance
6.1 Applicable Standards
- ASTM A213 / A213M: Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for High-temperature Service
- EN 10216-5: Non-ferrous metal tubes — Technical delivery conditions — Part 5: Seamless and welded stainless steel tubes
- ISO 15552: Welded stainless steel tubes for general purposes
- ASME Boiler & Pressure Vessel Code, Section VIII: For pressure-containing applications
- ASTM A403: Standard Specification for Stainless Steel Bars and Shapes (surface finish reference)
- 3-A Sanitary Standards: For food and pharmaceutical applications
- ISO 14644: Cleanroom-compatible surface quality (medical applications)
6.2 Quality Assurance Program
- ISO 9001:2015 Quality Management System certification
- ISO 14001:2015 Environmental Management System certification
- NADCAP Special Process Certification (welding, heat treatment)
- Mill Test Reports (MTR) provided with each batch, including chemical composition, mechanical properties, and non-destructive testing (NDT) results
- Third-party inspection available upon request (SGS, Bureau Veritas, DNV)
- Traceability: Full batch traceability from raw material coil to finished product
7. Unique Selling Points
7.1 Technological Differentiation
- Domestic Technology Integration: Incorporates advanced coil forming technology developed through domestic R&D programs, combining international best practices with localized manufacturing expertise.
- Extended Continuous Length: Capability to produce coils exceeding 1,000 meters without intermediate welds, surpassing typical industry standards of 500–800 meters.
- Multi-Grade Flexibility: Single production line capable of processing austenitic, duplex, and custom alloy grades with rapid changeover.
- Precision Dimensional Control: Achieves tolerances comparable to cold-drawn seamless tubing through advanced roll forming and calibration technology.
7.2 Commercial Advantages
- Cost Efficiency: 15–25% lower cost per meter compared to seamless tubing of equivalent specifications
- Lead Time Reduction: Continuous production eliminates batch processing delays; standard delivery within 15–20 business days
- Customization: Tailored specifications for diameter, wall thickness, surface finish, coil dimensions, and packaging
- Technical Support: Dedicated engineering team provides application-specific selection guidance and process optimization
8. Packaging & Delivery
- Coils are wrapped in moisture-proof kraft paper and protected with VCI (Vapor Corrosion Inhibitor) film
- Outer packaging: reinforced wooden pallets or steel crate options for export
- Each coil is labeled with product identification, heat number, dimensions, and quantity
- Available in standard coil configurations or custom packaging per customer specification
9. Conclusion
The Stainless Steel Coil Tube represents a high-performance, cost-effective alternative to traditional straight-length stainless steel tubing. Leveraging advanced coil forming technology, precision welding systems, and comprehensive quality control, this product delivers exceptional mechanical properties, corrosion resistance, and dimensional accuracy across a wide range of industrial applications. Wenzhou Jixing Metal Materials Co., Ltd. maintains a commitment to continuous technological improvement, ensuring that their coil tube products meet and exceed international quality standards while providing competitive value to customers worldwide.