Stainless Steel Coil Tube (Coil Tube) — Turntable/Cantilever Pay-Off Handling System
1. Product Overview
The Stainless Steel Coil Tube (Coil Tube) is a continuous-length tubular product supplied in the form of a coiled bundle, designed for efficient transport, storage, and on-site deployment in piping systems. The coil tube is wound into a compact spiral geometry, typically wound on a Turntable-Type (转盘式) or Cantilever-Type (悬臂式) Coil Pay-Off Device for controlled axial rotation and sequential unspooling. This product category falls under the Installation and Maintenance classification, specifically within the Coil Pay-Off Operation subcategory, utilizing a Specialized Pay-Off Stand (专用放线架) to ensure damage-free deployment.
The coil tube is laid flat on the turntable platform and released through axial rotation (axial rotation pay-out method), which preserves the geometric integrity of the tube and prevents plastic deformation during handling. This approach is critical for maintaining dimensional accuracy and surface finish quality throughout the installation lifecycle.
2. Material & Properties
2.1 Base Material Composition
Stainless steel coil tubes are manufactured from austenitic or duplex stainless steel grades, with the following typical material specifications:
| Property | Specification | Standard Reference |
|---|---|---|
| Material Grade (typical) | Austenitic 304 / 316L / Duplex 2205 | ASTM A554 / EN 10217 |
| Outer Diameter (OD) | 12 mm – 219 mm | ISO 4200 |
| Wall Thickness | 0.5 mm – 8.0 mm | ASTM A554 | Coil Diameter (Bundle) | 1,200 mm – 3,000 mm (ID/OD) | Manufacturer Specification |
| Coil Length | 50 m – 500 m (continuous) | Custom per Order |
| Surface Finish | 2B / BA (Bright Annealed) / No.4 / Hairline | ASTM A480 |
| Tensile Strength (304 grade) | ≥ 520 MPa | ASTM A554 |
| Yield Strength (304 grade) | ≥ 205 MPa | ASTM A554 |
| Elongation | ≥ 40% | ASTM A554 |
| Corrosion Resistance | Excellent (pitting resistance equivalent number, PREN ≥ 18 for 316L) | ASTM G48 |
2.2 Mechanical Behavior Under Coil Form
When wound into a coil, the stainless steel tube experiences elastic bending stress. The minimum bend radius during coiling must exceed the critical elastic limit to prevent permanent set or micro-cracking at the outer fiber. The coil tube retains its full mechanical properties provided the handling protocol is strictly followed — specifically, ground dragging is strictly prohibited, and any occurrence of kinking (扭结) results in immediate scrapping (报废) of the affected section.
3. Specifications — Turntable/Cantilever Pay-Off System
| Parameter | Turntable-Type (转盘式) | Cantilever-Type (悬臂式) |
|---|---|---|
| Pay-Off Method | Flat placement on rotating turntable; axial rotation release | Coil mounted on cantilever arm; controlled unwinding |
| Applicable Coil OD | ≤ 2,000 mm | ≤ 2,500 mm |
| Max Tube OD Supported | ≤ 114 mm | ≤ 219 mm |
| Max Coil Weight Capacity | ≤ 3,000 kg | ≤ 5,000 kg |
| Rotation Speed | 0 – 5 rpm (variable) | 0 – 3 rpm (variable) |
| Drive Mechanism | Electric motor with reducer; friction drive | Hydraulic or electric cantilever drive |
| Tube Placement | Flat on turntable platform (axial alignment) | Horizontal on cantilever cradle |
| Anti-Rotation Device | Required (to prevent coil migration) | Integrated into arm structure |
| Guide Roller Set | Top and bottom V-groove rollers | Top and bottom V-groove rollers |
| Emergency Stop | Yes (mushroom button + brake) | Yes (mushroom button + brake) |
| Ground Contact | Coil never contacts ground — suspended by turntable | Coil never contacts ground — supported by cantilever |
4. Manufacturing Process
4.1 Coil Tube Production
- Strip Supply (带材卷供): Stainless steel strip (coil) is fed from a large master coil into the forming line at controlled tension.
- Edge Trimming & Cleaning (修边与清洗): Strip edges are trimmed to precise width; surface is cleaned to remove oils and contaminants.
- Forming (成型): Multi-stand roll forming converts the flat strip into a circular tube cross-section. For larger diameters, a mandrel-assisted or seamless welding process is employed.
- Welding (焊接) — if applicable: TIG (Tungsten Inert Gas) or MIG welding is used for longitudinal seam joining, with helium back-purging to prevent internal oxidation.
- Heat Treatment (热处理): Solution annealing at 1,050–1,150 °C followed by rapid water quenching to achieve full austenitic microstructure and maximum corrosion resistance.
- Pickling & Passivation (酸洗钝化): Removal of mill scale and formation of a protective chromium oxide passivation layer (Cr₂O₃ film).
- Coiling (盘卷): The continuous tube is wound into a coil on a coiling mandrel under controlled tension. Coil diameter and lay are optimized for the target pay-off system.
- End Sealing & Packaging (端部密封与包装): Coil ends are sealed with protective caps; the entire coil is wrapped in moisture-barrier film and wooden pallets for shipment.
4.2 Pay-Off System Assembly
- Base Fabrication: Heavy-duty steel base frame is fabricated with vibration-damping mounts.
- Turntable/Cantilever Mounting: The rotating platform (turntable) or articulated arm (cantilever) is mounted with precision bearings (typically spherical roller bearings or slewing bearings).
- Drive Installation: Electric motor, gear reducer, and transmission coupling are installed with torque-limited clutch for overload protection.
- Roller Guide Assembly: V-groove guide rollers are positioned to support the tube at two points per span, preventing lateral displacement and ovalization.
- Control Panel Integration: Variable frequency drive (VFD), emergency stop circuit, and speed display are integrated into the operator control panel.
- Commissioning & Load Test: The system is load-tested with a representative coil to verify smooth rotation, absence of vibration, and proper brake engagement.
5. Applications
5.1 Coil Tube Applications
- Chemical Processing Industry (化工行业): Piping systems for acids, alkalis, and corrosive fluids where continuous lengths eliminate joint leakage points.
- Food & Beverage Industry (食品饮料): Sanitary-grade piping (316L, electropolished) for CIP/SIP compatible fluid transfer.
- Pharmaceutical Manufacturing (制药): High-purity process lines requiring weld-free continuous runs.
- Oil & Gas (油气): Subsea and offshore piping where coil deployment reduces installation time and dive operations.
- Power Generation (电力): Heat exchanger tubes, condensate lines, and boiler auxiliary piping.
- Architectural & Structural (建筑): Decorative railings, curtain wall support tubes, and structural bracing.
- Automotive & Aerospace (汽车航空): Fuel lines, exhaust components, and hydraulic tubing.
5.2 Pay-Off System Applications
- On-Site Installation (现场安装): Controlled deployment of coil tube on construction sites, reducing handling damage and installation labor.
- Welding & Fabrication Shops (焊接加工车间): Feeding coil tube into automated welding machines, bending machines, and cutting stations.
- Shipbuilding (造船): Deck-level coil tube deployment for hull piping installation.
- Pipeline Construction (管道施工): Field deployment of pre-fabricated coil pipe sections for trenchless or open-cut installation.
6. Quality Certifications & Standards Compliance
| Certification / Standard | Scope | Relevance |
|---|---|---|
| ISO 9001:2015 | Quality Management System | Ensures consistent manufacturing quality across production batches |
| ISO 14001:2015 | Environmental Management System | Sustainable production practices and waste minimization |
| ISO 45001:2018 | Occupational Health & Safety | Safe handling protocols for coil tube and pay-off equipment |
| EN 10204 3.1 | Material Test Certificate | Third-party verified material compliance documentation |
| ASME BPVC Section IX | Welding Qualification | Welded joint qualification for pressure-containing applications |
| CE Marking (EU) | European Conformity | Compliance with EU Machinery Directive 2006/42/EC for pay-off equipment |
| UL / CSA | Electrical Safety | Electrical components of pay-off drive system certification |
| NACE MR0175 / ISO 15156 | Sour Service | Material suitability for H₂S-containing environments |
7. Critical Handling Protocol — Key Performance Indicators
WARNING: Ground dragging of the coil tube is STRICTLY PROHIBITED (严禁地面拖拽). Any occurrence of kinking (扭结) — defined as a localized plastic deformation where the tube axis deviates by more than 5° from the original helical path — results in immediate scrapping (报废) of the affected coil section. Kinking compromises the structural integrity, creates stress concentration points, and may initiate intergranular corrosion or stress corrosion cracking (SCC) in service.
7.1 Mandatory Handling Requirements
- Turntable Placement: The coil tube must be placed flat and centered on the turntable platform, with the tube axis aligned parallel to the turntable rotation axis.
- Axial Rotation Release: Unspooling is achieved exclusively through controlled axial rotation of the turntable. No manual pulling or dragging of the tube from the coil is permitted.
- Roller Support: V-groove rollers must be positioned at intervals not exceeding 3.0 m to prevent tube sagging and ovalization.
- Tension Control: The pay-off tension must not exceed the elastic limit of the tube wall. Recommended maximum tension: 0.5 × yield strength × cross-sectional area.
- Inspection Points: Visual and dimensional inspection at every 50 m of unspooled length to detect early signs of kinking, ovality, or surface damage.
- Temperature Control: Coil tube must not be exposed to ambient temperatures below the ductile-to-brittle transition temperature of the specific grade during handling.
8. Unique Selling Points
- Zero-Damage Deployment: The turntable/cantilever pay-off system eliminates all ground-contact scenarios, ensuring the coil tube retains its as-manufactured surface finish and dimensional accuracy throughout installation.
- Kinking Prevention: Axial rotation pay-out inherently prevents the torsional and bending overload conditions that cause kinking, thereby protecting the investment in premium-grade stainless steel material.
- Continuous-Length Advantage: Coil tube eliminates field welds and flanged joints, reducing potential leak points and maintenance requirements — a critical advantage in high-integrity piping systems.
- Installation Efficiency: The controlled pay-off system enables rapid, continuous deployment, reducing installation time by up to 40% compared to cut-length tube installation with individual joint assembly.
- Modular Equipment Design: The pay-off stand is designed for quick setup and relocation, compatible with both indoor fabrication shops and outdoor construction sites.
- Traceability: Each coil tube batch is accompanied by a full material traceability package (heat number, chemical analysis, mechanical test results, and dimensional certificate) in compliance with EN 10204 3.1 requirements.
9. Conclusion
The Stainless Steel Coil Tube, when deployed through a properly engineered turntable or cantilever pay-off system, represents the optimal solution for high-integrity, continuous-length piping applications. The strict adherence to axial-rotation pay-out methodology — with absolute prohibition of ground dragging and immediate scrapping upon kinking detection — ensures that the full material performance of the stainless steel tube is preserved from factory to final service condition. This product system, manufactured and supplied by Wenzhou Jixing Metal Materials Co., Ltd., meets international standards for material quality, equipment safety, and installation reliability.