Stainless Steel Coil Tube — Water-Assisted Coiling Process (Product No. 1630)

Product Overview

The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. represents a next-generation product line distinguished by its innovative manufacturing methodology: the Water-Substitution-for-Sand Coiling Process (以水代砂盘管工艺). This proprietary technique replaces traditional abrasive sand filling with pressurized water as the internal support medium during the coiling and forming of stainless steel tubing. The result is a coil tube product with superior surface integrity, reduced contamination risk, enhanced dimensional accuracy, and improved post-processing efficiency — setting a new benchmark in the stainless steel seamless tube industry.

Coil tubes are supplied in continuous coil form, offering significant material utilization advantages over straight-length pipe, and are widely deployed in heat exchangers, chemical processing, food and beverage equipment, pharmaceutical manufacturing, and energy systems.

Material & Properties

Wenzhou Jixing Metal Materials Co., Ltd. produces coil tubes from a range of austenitic and duplex stainless steel grades conforming to international standards:

Typical available grades include:

Key material properties of the coil tube product:

Specifications

Parameter Specification Range Standard Reference
Outer Diameter (OD) 6.0 mm – 168.0 mm (¼" – 6") ASTM A269 / EN 10216-5
Wall Thickness 0.5 mm – 8.0 mm ASTM A269 / GB/T 13296
Coil Length Customizable; typically 20 m – 100 m per coil —
Coil Inner Diameter 300 mm – 1,200 mm (customizable) —
Dimensional Tolerance ±0.10 mm (OD); ±10% (Wall Thickness) ASTM A269 / ASME SA-269
Available Grades 304, 304L, 316, 316L, 321, 316Ti, 904L, 2205 ASTM / EN / GB
Surface Finish Pickled & Passivated (P&P); Mirror Polished (Ra ≤ 0.4 μm); Matte / Brushed ASTM A269 / EN 10216-5
Manufacturing Method Seamless (Pierced / Cold-Drawn) or Welded (ERW / TIG) with Water-Assisted Coiling Internal Process Specification
Delivery Condition Annealed (Solution Annealed), Pickled & Passivated ASTM A269
End Treatment Plain ends, beveled ends, or threaded (on request) ASME B1.20.1

Manufacturing Process — Water-Assisted Coiling Technology

The core differentiator of this product line is the Water-Assisted Coiling Process (以水代砂盘管工艺), a proprietary technique developed and refined by Wenzhou Jixing Metal Materials Co., Ltd. The following outlines the complete manufacturing sequence:

  1. Raw Material Selection & Incoming Inspection:
    Stainless steel billets or seamless pipe blanks are sourced from certified mills. Each lot undergoes spectroscopic analysis (PMI), chemical composition verification, and mechanical property testing to ensure conformance with the specified grade and standard.
  2. Piercing & Hot Rolling:
    For seamless production, solid billets are heated to 1,100–1,250°C and pierced to produce hot-rolled seamless tube blanks. For welded production, precision-rolled coil strip is formed and resistance-welded (ERW) or gas-tungsten arc welded (TIG).
  3. Cold Drawing & Sizing:
    Hot-rolled blanks are cold-drawn through calibrated dies to achieve precise outer diameter and wall thickness tolerances. Multiple drawing passes may be employed for tighter tolerances.
  4. Water-Assisted Coiling (Core Innovation):
    During the coiling stage — where straight tube is wound into coil form — pressurized water is introduced into the tube bore to serve as an internal support medium, replacing the traditional practice of filling the tube with fine sand or granular material. This process delivers the following critical advantages:
    • Elimination of Abrasive Contamination: No sand or particulate residue remains within the tube bore, eliminating a common source of surface damage, flow obstruction, and downstream cleaning costs.
    • Superior Surface Integrity: The smooth hydraulic support prevents localized wall deformation and micro-scratching that sand particles can cause during coiling and handling.
    • Enhanced Dimensional Stability: Water provides uniform, isotropic radial pressure, resulting in more consistent ovality control (typically ≤ 1% of OD) throughout the coil length.
    • Reduced Post-Processing: Eliminates the need for high-pressure abrasive blasting or chemical cleaning of the internal bore, reducing production cycle time and chemical waste.
    • Environmental Sustainability: Water is fully recoverable and recyclable within a closed-loop system, reducing hazardous waste generation associated with sand disposal.
  5. Solution Annealing & Pickling:
    Coiled tubes are solution annealed at 1,050–1,150°C (air-cooled or controlled cooling) to relieve cold-work stresses and restore full austenitic microstructure. Subsequently, tubes are pickled in a citric acid or dilute nitric/hydrofluoric acid solution to remove oxide scale, followed by passivation to establish a stable chromium oxide passive layer.
  6. Surface Finishing (Optional):
    Mirror polishing (electrolytic or mechanical) is available for applications requiring ultra-low surface roughness (Ra ≤ 0.4 μm), such as pharmaceutical and food-grade systems.
  7. Final Inspection & Testing:
    Each coil undergoes comprehensive quality verification:
    • Visual inspection of internal and external surfaces
    • Dimensional measurement (OD, wall thickness, ovality)
    • Hydrostatic pressure testing (typically 2× working pressure, minimum 50 bar)
    • Eddy current testing (ECT) for internal and external flaw detection
    • Spectroscopic chemical analysis (PMI verification)
    • Intergranular corrosion testing (ASTM A269 / ASTM G48)
  8. Packaging & Shipping:
    Coils are wrapped in protective plastic film, strapped with steel bands, and secured on wooden pallets or skids. Export packaging conforms to ISPM-15 (International Standards for Phytosanitary Measures) for heat-treated or fumigated wood.

Applications

Stainless steel coil tubes produced via the water-assisted coiling process serve a broad spectrum of industrial applications, particularly where internal surface cleanliness, corrosion resistance, and dimensional precision are critical:

Quality Certifications & Compliance

Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems and holds the following certifications and complies with the following standards:

Unique Selling Points

The Water-Assisted Coiling Process is the defining innovation that distinguishes this product line from conventionally manufactured stainless steel coil tubes.

  1. Zero Abrasive Contamination: Complete elimination of sand or particulate residue inside the tube bore — a critical advantage for hygiene-sensitive and flow-critical applications.
  2. Superior Internal Surface Quality: Hydraulic support during coiling produces a smoother, more uniform internal surface with reduced risk of micro-damage, directly improving fatigue life and flow efficiency.
  3. Enhanced Dimensional Consistency: Uniform radial water pressure yields tighter control over ovality and wall thickness variation along the entire coil length.
  4. Reduced Total Cost of Ownership (TCO): Elimination of downstream internal cleaning operations reduces processing time, labor costs, and chemical consumption.
  5. Environmental Advantage: Closed-loop water recovery system eliminates hazardous sand waste, aligning with ESG (Environmental, Social, and Governance) sustainability goals.
  6. Full Traceability: Every coil is traceable to its mill heat number with complete test documentation, ensuring supply chain integrity and regulatory compliance.
  7. Customization Capability: Flexible production parameters accommodate non-standard diameters, wall thicknesses, coil configurations, and surface finishes to meet project-specific requirements.

Technical Data Sheet Reference

For detailed material