Ultra-Long Stainless Steel Coil Tube (500m – 2000m+/Coil)

1. Product Overview

The Ultra-Long Stainless Steel Coil Tube represents a premium-grade continuous coiled tubing solution engineered for demanding industrial applications where extended length without intermediate joints is a critical requirement. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd., this product category delivers coil lengths ranging from 500 meters to over 2,000 meters per coil, setting it apart from standard coil tube offerings that typically max out at shorter lengths.

Unlike conventional pipe sections that require field welding or mechanical couplings at regular intervals, the ultra-long coil tube is supplied as a single continuous length wound onto a heavy-duty coil drum. This eliminates the need for numerous intermediate connections, significantly reducing potential failure points, installation time, and total cost of ownership in offshore, subsea, and long-distance pipeline applications.

The fundamental value proposition of this product lies in its ability to provide joint-free continuous runs of stainless steel tubing over distances that would otherwise necessitate multiple splices. This capability is particularly transformative in subsea engineering, where each joint represents a potential integrity risk, a maintenance liability, and an added cost center.

2. Material Composition & Properties

Ultra-long coil tubes are typically fabricated from high-performance austenitic stainless steel grades selected for their combination of corrosion resistance, mechanical strength, and formability — properties essential for maintaining structural integrity over extended continuous lengths.

2.1 Common Material Grades

2.2 Key Mechanical Properties

2.3 Surface Finish Options

3. Technical Specifications

Parameter Specification Range Standard / Reference
Coil Length 500 m – 2,000 m+ per coil Custom order basis
Outer Diameter (OD) 3.175 mm – 114.3 mm (1/8" – 4-1/2") ASTM A554 / A511
Wall Thickness 0.3 mm – 6.0 mm (subject to OD) ASTM A511 / EN 10217
Coil Inner Diameter (CID) 500 mm – 1,500 mm (drum-dependent) Custom specification
Coil Weight Up to 20–30 tonnes per coil (grade-dependent) Transportation limits
Maximum Continuous Length 2,000+ meters without interruption Proprietary manufacturing capability
Surface Tolerance ±0.02 mm per 100 m Internal quality standard
Dimensional Tolerance (OD) ±0.05 mm to ±0.10 mm ASTM A511 Class 1 / EN 10217
Dimensional Tolerance (WT) ±10% of nominal wall thickness ASTM A511 / A554
Minimum Bend Radius 3D – 5D (D = outer diameter) Grade and condition dependent
Operating Temperature Range –196°C (LN₂) to +870°C (austenitic grades) ASTM A270
Pressure Rating Up to 400 bar (depending on OD/WT) ASME B31.3 / B31.8
End Condition Flush cut, chamfered, or beveled Customer specification
Packaging Steel coil drum with protective wrapping, VCI film, and moisture barrier ISO 11607 / customer spec

4. Manufacturing Process

The production of ultra-long stainless steel coil tubes demands exceptional process control, specialized equipment, and rigorous quality assurance at every stage. The manufacturing workflow is as follows:

  1. Raw Material Selection & Verification:

    High-quality stainless steel strip or wire rod is procured from certified mills and subjected to spectrographic analysis to verify chemical composition compliance with the specified grade (e.g., ASTM A276, EN 10088). Each heat lot is traceable through mill test certificates.

  2. Coil Forming / Cold Drawing:

    For smaller diameters, continuous cold-drawing through precision tungsten carbide or diamond dies is employed to achieve the target OD and wall thickness. For larger diameters, a forming process using roller or plate-to-tube (P2T) technology creates the seamless tube from flat strip.

  3. Welding (where applicable):

    In the case of welded coil tube, high-frequency induction welding (HF-IW) or orbital TIG welding is used to create a longitudinal seam. The weld zone is precisely controlled to ensure metallurgical homogeneity and mechanical equivalence to the base metal. Weld bead height is typically ground flush to within ±0.02 mm.

  4. Heat Treatment / Annealing:

    Post-weld or post-forming annealing is performed at 1050–1150°C followed by rapid quenching (water or controlled atmosphere) to restore full austenitic microstructure, eliminate residual stresses, and achieve maximum ductility for subsequent coiling operations.

  5. Precision Coiling:

    The continuous tube is wound onto a heavy-duty coil drum using a computer-controlled coiling system that maintains uniform tension throughout the entire length. The coiling process is monitored for:

    • Consistent coil layer-to-layer spacing
    • Uniform tension to prevent kinking or ovality
    • Smooth start and end transitions to avoid surface damage

  6. Quality Inspection & Testing:

    Every coil undergoes comprehensive inspection including:

    • Visual Inspection: Full-length surface examination for defects, weld imperfections, or mechanical damage
    • Dimensional Verification: OD, wall thickness, and coil diameter measured at multiple points along the length
    • Hydrostatic / Pneumatic Testing: Pressure testing at 1.5× the maximum design pressure for the full coil length
    • Eddy Current Testing (ECT): Non-destructive testing for subsurface and surface defects along the weld seam
    • Chemical Analysis: Spectrographic confirmation of grade compliance
    • Mechanical Testing: Tensile and hardness testing on coupon samples from each heat lot

  7. Protective Packaging & Shipping:

    Completed coils are wrapped with VCI (Volatile Corrosion Inhibitor) film, moisture-absorbing desiccant packs, and heavy-duty stretch film. Coils are secured on steel drums with wooden or steel cradles for maritime or overland transport. Each shipment is accompanied by a full quality dossier including mill test certificates, inspection reports, and certificates of conformance.

5. Applications

The ultra-long coil tube's defining advantage — continuous length without intermediate joints — positions it uniquely for applications where connection points represent unacceptable risk or cost. Key application sectors include:

5.1 Subsea Umbilical Cables

Subsea umbilicals are multi-functional bundles that transmit power, fluids, and data between the sea surface and offshore production equipment. The stainless steel coil tube serves as the structural and fluid-carrying conduit within these umbilicals. Ultra-long coil lengths dramatically reduce the number of field splices required during installation, thereby:

5.2 Long-Distance Pipeline Systems

In onshore and offshore long-distance pipeline networks, ultra-long coil tubes enable continuous runs through difficult terrain, reducing the number of joints and associated installation complexity. Applications include:

5.3 Offshore Platform Piping

Offshore production platforms benefit from ultra-long coil tube in process, fire water, and utility piping systems. The reduced number of joints translates to fewer inspection points, lower maintenance frequency, and improved platform safety margins.

5.4 Energy & Power Generation

5.5 Aerospace & Defense

5.6 Medical & Pharmaceutical

6. Unique Selling Points

7. Quality Certifications & Standards Compliance

Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management and product certification systems ensuring full compliance with international standards:

7.1 Quality Management System