Stainless Steel Coil Tube (Coiltube) — Ultra-Long Pumping-Grade Specification
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd. | Catalog No.: 407
1. Product Overview
The Stainless Steel Coil Tube (盘管, Coiltube) is a continuous, pre-formed tubular product manufactured in a helical coil configuration, designed for deployment in applications requiring extended reach without the need for field jointing or welding. This product line is engineered specifically for demanding environments where ultra-long delivery distances, resistance to aggressive media, and structural integrity are paramount.
The coil tube concept draws upon research findings in Lightweight Ultra-High Performance Concrete (LUHPC) Ultra-Long Coil Tube Pumping Performance, which demonstrated that continuous coiled configurations significantly reduce pressure losses, eliminate leak-prone joints, and enable single-pass delivery of viscous composite materials over distances exceeding conventional straight-pipe systems. The stainless steel variant of this product provides superior corrosion resistance, mechanical durability, and hygiene compliance compared to carbon steel or polymer alternatives, making it suitable for both civil engineering and industrial process applications.
2. Material & Properties
2.1 Base Material Grades
- AISI 304 (UNS S30400): General-purpose austenitic stainless steel; excellent corrosion resistance in mild to moderate environments; non-magnetic; suitable for food-grade and atmospheric applications.
- AISI 316 / 316L (UNS S31600 / S31603): Molybdenum-enhanced austenitic stainless steel; superior resistance to chlorides, acids, and marine environments; preferred for chemical processing and coastal installations.
- AISI 321 / 347 (UNS S32100 / S34700): Stabilized austenitic grades; resistant to intergranular corrosion at elevated temperatures; suitable for high-temperature process lines.
- Duplex 2205 (UNS S31803): Duplex austenitic-ferritic stainless steel; approximately twice the yield strength of 304; excellent resistance to chloride stress corrosion cracking (CSCC); ideal for high-pressure and high-corrosion environments.
2.2 Key Mechanical Properties (Typical for Grade 304, Annealed)
- Tensile Strength (UTS): 515–750 MPa (75–109 ksi)
- Yield Strength (0.2% Offset): ≥ 205 MPa (29.7 ksi)
- Elongation at Break: ≥ 40% (A50mm)
- Hardness (HB): ≤ 217
- Modulus of Elasticity: 193 GPa (28,000 ksi)
2.3 Corrosion & Environmental Performance
- Corrosion resistance in aerated water: < 0.01 mm/year (Grade 316L)
- Pitting Resistance Equivalent Number (PREN): 18–20 (304); 24–26 (316L); 34–38 (2205)
- Operating temperature range: −196°C to +870°C (304/316); up to +450°C (2205)
- Non-magnetic in annealed condition (austenitic grades)
3. Specifications
| Parameter | Specification / Range |
|---|---|
| Outer Diameter (OD) | 6 mm – 325 mm (⅛" – 12") |
| Wall Thickness | 0.5 mm – 12 mm (0.020" – 0.472") |
| Coil Length (Continuous) | 50 m – 500 m (custom up to 1,000 m per research protocols) |
| Coil Inner Diameter (Winding) | 1,200 mm – 3,500 mm (4.9 ft – 11.5 ft) |
| Standard Length (Cut-to-Length) | 3 m, 6 m, 12 m, or custom |
| Surface Finish | Mirror polished (Ra ≤ 0.1 μm); Electropolished; Brushed; Pickled & Passivated; 2B |
| End Form | Plain; Beveled (37° or 60°); Threaded; Flanged; Socket-welded |
| Tolerance (OD) | ±0.15 mm (standard); ±0.05 mm (precision) |
| Tolerance (Wall Thickness) | ±10% (standard); ±5% (precision) |
| Applicable Standards | ASTM A269, ASTM A213, ASTM A554, EN 10216-5, EN 10217-7, JIS G3459, GB/T 12771 |
| Packaging | Steel coil core with protective wrapping; wooden pallet; VCI (Vapor Corrosion Inhibitor) paper |
4. Manufacturing Process
4.1 Production Workflow
- Hot-Rolled Strip Production: Stainless steel ingots are continuously cast and hot-rolled into strip of specified thickness. The strip undergoes descaling and edge trimming.
- Cold Reduction: The strip is cold-rolled to achieve precise final wall thickness and surface quality. Intermediate annealing steps may be applied to restore ductility and prevent work-hardening.
- Pickling & Annealing: The cold-rolled strip is pickled in mixed acid (HNO₃/HF) to remove oxide scale and carbon contamination, then annealed in a controlled-atmosphere furnace (H₂ or vacuum) to achieve the desired crystallographic structure and mechanical properties.
- Passivation: A final acid passivation treatment (typically 20% HNO₃ or citric acid solution) forms a stable chromium oxide passive film on the surface, enhancing corrosion resistance.
- Forming (Coiling): The flat strip is fed through a series of progressively reducing roll-forming stations that incrementally bend the strip into a helical coil. The forming process is controlled to maintain dimensional accuracy and avoid excessive plastic strain.
- Welding (if applicable): For welded coil tubes, the helical seam is welded using Automatic Underwater TIG (A-WUT) or Orbital TIG welding, followed by inline ultrasonic testing (UT) for weld integrity verification.
- Coil Winding: The formed tube is wound onto a large-diameter coil mandrel in a controlled manner to achieve uniform coil diameter and layer spacing.
- Quality Inspection: Each coil undergoes dimensional measurement, visual inspection, hydrostatic pressure testing, and optional spectroscopic analysis (PMI — Positive Material Identification) for chemical composition verification.
- Packaging & Dispatch: Coils are protected with VCI wrapping, secured to steel cores, and packed on wooden pallets for shipment.
4.2 Ultra-Long Coil Tube Pumping Design Considerations
In applications involving the pumping of viscous fluids — such as Lightweight Ultra-High Performance Concrete (LUHPC) — the coil tube configuration offers distinct hydraulic advantages:
- Reduced Pressure Drop: The continuous helical geometry eliminates couplings and joints that create localized pressure losses in segmented pipe systems.
- Controlled Flow Profile: The uniform curvature of the coil promotes laminar-to-turbulent transition management, reducing segregation and bleeding of composite materials.
- Extended Delivery Reach: Single coils up to 500 m enable delivery to remote placement points without intermediate pump stations.
- Self-Supporting Structure: The coil configuration provides inherent structural rigidity, reducing the need for external support brackets during deployment.
5. Applications
5.1 Civil Engineering & Construction
- Post-tensioning ducts and sheathing for prestressed concrete structures
- Embedded conduits for reinforcement tendons in bridges, tunnels, and high-rise buildings
- Ultra-long pumping lines for LUHPC, self-compacting concrete (SCC), and grout delivery
- Fire suppression and sprinkler systems in corrosive industrial environments
5.2 Industrial Process & Chemical
- Chemical processing pipelines for aggressive media (acids, chlorides, solvents)
- Pharmaceutical and bioprocess transfer lines requiring sanitary-grade tubing
- Food and beverage processing (dairy, brewing, beverage) — 304/316L grades
- Heat exchanger coil assemblies and refrigeration circuits
5.3 Marine & Offshore
- Ballast water systems, fuel transfer lines, and hydraulic circuits on vessels
- Offshore platform utility lines (seawater injection, chemical dosing)
- Desalination plant piping (2205 duplex for high-salinity environments)
5.4 Energy & Power
- Geothermal well tubing and circulation lines
- Nuclear-grade process piping (316L, 321, 347)
- Hydrogen fuel cell and electrolysis system tubing
6. Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring traceability and conformity to international standards:
| Certification / Standard | Scope |
|---|---|
| ISO 9001:2015 | Quality Management System |
| ISO 14001:2015 | Environmental Management System |
| ISO 45001:2018 | Occupational Health & Safety Management |
| EN 10204 3.1 | Inspection Certificate — Material Test Reports (MTR) with third-party verification |
| ASME Section IX | Welding procedure qualification (for welded coil variants) |
| 3-A Sanitary Standards | Dairy and food-grade equipment (applicable to sanitary surface finish grades) |
| CE Marking (PED 2014/68/EU) | Pressure Equipment Directive compliance for pressure-rated applications |
| NSF/ANSI 61 | Drinking water system components (material safety) |
6.1 Testing & Inspection Protocols
- Chemical Analysis: Spectrographic verification of Ni, Cr, Mo, C, Si, Mn content per ASTM A276 / A270
- Mechanical Testing: Tensile, hardness, and impact testing per ASTM A370 / A502
- Dimensional Inspection: Optical and laser-based measurement of OD, wall thickness, and straightness
- Hydrostatic Pressure Test: All coils tested at 1.5× maximum working pressure, held for minimum 5 seconds with zero leakage
- Non-Destructive Testing (NDT): Ultrasonic (UT) and magnetic particle inspection (MT) for weld integrity and surface defect detection
- Pitting & Intergranular Corrosion Testing: ASTM A967 (intergranular), ASTM G48 (pitting) for critical applications
- Positive Material Identification (PMI): XRF (X-ray Fluorescence) analysis on each heat lot
7. Unique Selling Points
Ultra-Long Continuous Delivery: Coils up to 500 m eliminate the need for field jointing, reducing installation time by up to 60% and eliminating potential leak points that plague segmented pipe systems.
Research-Validated Pumping Performance: Design parameters informed by peer-reviewed research on LUHPC pumping dynamics, ensuring optimal hydraulic performance for high-viscosity, high-density composite material delivery.
Multi-Grade Material Flexibility: From standard 304 to duplex 2205, the product range covers the full spectrum of corrosion and mechanical performance requirements without compromising coil geometry consistency.
Hygienic & Chemical Resistance: Mirror-polished and electropolished finishes achieve surface roughness below Ra 0.1 μm, meeting pharmaceutical and food-grade standards while resisting biofilm formation.
Full Traceability & Certification: Every coil is accompanied by a complete EN 10204 3.1 material test report with spectrographic verification, ensuring full material traceability from mill to installation.
Document Reference: Catalog No. 407 — Coiltube Series | Wenzhou Jixing Metal Materials Co., Ltd. | Technical Literature Study Reference: Lightweight UHPC Ultra-Long Coil Tube Pumping Performance Research