Ultra-Long Stainless Steel Coil Tube — 500 m to 2000 m+ per Spool
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. specializes in the manufacture of extra-long stainless steel coil tubes ranging from 500 metres to over 2000 metres per spool. These ultra-long coils represent a significant advancement in stainless steel tubing technology, engineered to minimize field joints, reduce installation complexity, and deliver superior reliability in demanding offshore and long-distance pipeline applications.
Unlike conventional short-length tubes that require multiple welding joints during installation, ultra-long coil tubes are delivered as continuous, flexible lengths that can be unspooled directly onto the seabed or deployed along long pipeline routes. This capability dramatically reduces the number of in-situ connections, thereby lowering the risk of leak points and improving the overall integrity of the pipeline system.
Material & Properties
Available Grades
- Austenitic grades: 304, 304L, 316, 316L, 321, 347
- Super-austenitic grades: 904L, 254 SMO (UNS S31803)
- Duplex grades: 2205 (UNS S31803), 2507 (UNS S32750)
- Other grades upon request
Key Mechanical & Physical Properties
- Corrosion resistance: Excellent resistance to chlorides, sulfuric acid, and marine environments; particularly suited for offshore and subsea deployment.
- Tensile strength: Typically 515–720 MPa depending on grade and condition.
- Elongation: ≥ 40% (annealed condition), ensuring superior formability and flexibility during coiling and unspooling operations.
- Temperature range: Operational from cryogenic temperatures (−196 °C) up to 870 °C (austenitic grades), maintaining mechanical integrity without brittle fracture.
- Non-magnetic: Austenitic grades are inherently non-magnetic, ideal for sensitive instrumentation environments.
- Hygienic surface finish: Available in 2B, BA (bright annealed), pickled, and polished finishes with surface roughness as low as Ra 0.4 μm.
Specifications
| Parameter | Specification | Notes |
|---|---|---|
| Coil Length | 500 m – 2000 m+ per spool | Custom lengths available upon request |
| Outer Diameter (OD) | 6.0 mm – 159.0 mm (0.24 in – 6.26 in) | Wider range available for special orders |
| Wall Thickness | 0.5 mm – 6.0 mm (0.020 in – 0.236 in) | Thin-wall configurations optimized for flexibility |
| Coil Inner Diameter | 200 mm – 600 mm (7.87 in – 23.62 in) | Selected based on OD and wall thickness |
| Material Grades | 304, 304L, 316, 316L, 2205, 2507, 904L, 254 SMO | Full mill certificate traceability |
| Manufacturing Method | Seamless (hot-rolled / cold-drawn) or welded (ERW / EFW) | Seamless preferred for pressure and subsea service |
| Surface Finish | 2B, BA, Pickled, Polished (Ra ≤ 0.4 μm) | Custom finishes available |
| Heat Treatment | Annealed / Solution treated | Ensures maximum ductility for coiling |
| Standards Compliance | ASTM A269, ASTM A312, EN 10216-5, EN 10217-7, GB/T 12771 | Multi-standard certification available |
| Packaging | Wooden or steel spool with moisture-proof wrapping | Export-grade packaging for sea freight |
| Typical Tolerance (OD) | ± 0.10 mm – ± 0.30 mm | Tighter tolerances available on request |
Manufacturing Process
The production of ultra-long stainless steel coil tubes demands exceptional process control and precision engineering at every stage. Wenzhou Jixing employs a rigorous multi-step manufacturing workflow:
- Raw Material Selection: High-purity stainless steel slabs or ingots are sourced from certified mills, with full chemical composition verification via spectroscopic analysis.
- Hot Rolling / Billet Extrusion: Steel billets are hot-rolled or extruded into seamless tube blanks, establishing the initial geometry and microstructure.
- Cold Drawing / Cold Pilgering: The tube blanks undergo multiple passes through precision-drawn dies to achieve the target OD, wall thickness, and dimensional tolerances. This cold working step also enhances mechanical properties.
- Solution Annealing: Tubes are heat-treated in a controlled atmosphere furnace at temperatures between 1050 °C and 1150 °C, followed by rapid quenching. This process dissolves carbides, restores full ductility, and ensures maximum corrosion resistance — a critical requirement for the extreme flexibility needed during coiling.
- Precision Coiling: The annealed tubes are fed onto a precision winding system under carefully controlled tension and curvature. The coil winding parameters (tension, speed, inner diameter) are optimized to prevent kinking, ovality, or residual stress. Each coil is formed to the required length of 500 m to 2000 m+ without interruption.
- End Protection: Tube ends are fitted with protective caps or plugs to prevent contamination, mechanical damage, and corrosion during storage and transportation.
- Quality Inspection: Every coil undergoes comprehensive non-destructive testing (NDT), including 100% eddy current testing, hydrostatic pressure testing, dimensional verification, and surface inspection.
- Packaging & Dispatch: Coils are secured on export-grade wooden or steel spools, wrapped with moisture-proof materials, and prepared for international shipment.
Applications
The ultra-long stainless steel coil tube is purpose-engineered for applications where continuous, joint-free deployment is critical:
- Submarine Umbilical Cables: Used as the protective conduit or pressure-containing tube within subsea umbilicals that deliver power, hydraulic fluid, and chemical injection to offshore platforms and subsea production systems. The ultra-long coil length minimizes the number of in-situ joints on the seabed, significantly improving system reliability and reducing maintenance requirements.
- Long-Distance Pipelines: Ideal for oil, gas, and chemical pipelines spanning long distances where reducing the number of field welds is essential for leak prevention and operational safety.
- Offshore & Subsea Production Systems: Deployed in subsea tree manifolds, flowlines, and tie-back lines where joint reduction directly translates to improved system integrity.
- Chemical Processing: Long continuous runs in chemical plants where joint-free piping reduces contamination risk and simplifies inspection.
- Food & Pharmaceutical Processing: Sanitary-grade ultra-long coils enable continuous, joint-free piping layouts that meet the highest hygienic standards.
- Power Generation: Used in desalination plants, nuclear facilities, and thermal power stations for long continuous process lines.
Unique Selling Points
- Industry-Leading Coil Lengths: Delivering coils up to 2000 m+ per spool — substantially exceeding the typical 50–200 m range of standard coil tubes — enabling true continuous deployment in subsea and long-distance applications.
- Significantly Reduced Field Joints: Each 2000 m coil eliminates up to 40+ field welds compared to conventional 50 m lengths, dramatically improving pipeline integrity and reducing installation costs.
- Superior Formability: Precision annealing ensures the tube maintains full ductility throughout the coil length, preventing kinking, cracking, or deformation during unspooling and installation.
- Full Traceability: Every coil is accompanied by a complete material traceability dossier, including mill certificates, chemical analysis, mechanical test reports, and NDT records.
- Multi-Grade Flexibility: Availability across austenitic, super-austenitic, and duplex grades allows customers to match material properties precisely to their operating environment.
- Export-Grade Quality: Manufactured to international standards (ASTM, EN, ISO) with export-ready packaging for global delivery.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications to ensure product conformity and customer confidence:
- ISO 9001:2015 — Quality Management Systems certification, demonstrating a commitment to consistent quality and continuous improvement.
- ISO 14001:2015 — Environmental Management Systems certification, ensuring environmentally responsible manufacturing practices.
- ISO 45001:2018 — Occupational Health and Safety Management Systems certification.
- EN 10204 Type 3.1 — Third-party inspection certificates for all product batches, confirming compliance with specified standards.
- API 5L / API 5CT — Available for oil and gas industry applications upon request.
- NACE MR0175 / ISO 15156 — Compliance for materials used in sour service environments.
- DNV / Lloyd's Register — Third-party inspection and material certification for offshore and marine applications.
Quality Assurance Commitment: Every coil produced by Wenzhou Jixing undergoes 100% non-destructive testing, including eddy current inspection for wall thickness and flaw detection, hydrostatic pressure testing at 1.5× the maximum working pressure, and full dimensional verification against the applicable standard. Full chemical and mechanical test reports are provided with each shipment.