Stainless Steel Coil Tube (盘管 Coiltube) — Product Technical Specification
1. Product Overview
The Stainless Steel Coil Tube (also known as 盘管 or Coiltube) is a continuous-length tubular product formed by cold-drawing or hot-rolling processes and wound into a helical coil configuration. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd, this product line represents a critical intermediate form in the stainless steel pipe and tube industry, serving as a versatile feedstock for downstream processing into straight-length tubes, seamless pipes, and precision components.
Coil tubes are distinguished from conventional straight tubes by their continuous wound geometry, which enables high-efficiency transport, storage, and downstream forming operations. The product is particularly valued in applications requiring uniform wall thickness, high dimensional accuracy, and superior mechanical properties without the introduction of weld seams.
The production of coil tubes demands sophisticated handling infrastructure. A key element of the coil tube production line is the Intelligent Overhead Bridge Crane (智能桥式起重机), which facilitates automated loading, unloading, and material transfer of heavy coil bundles with precision positioning, thereby minimizing deformation risks and maximizing production throughput.
2. Material & Properties
2.1 Common Material Grades
Stainless steel coil tubes are available in a wide range of austenitic, ferritic, duplex, and precipitation-hardening grades conforming to international standards including ASTM (American Society for Testing and Materials), EN (European Norm), GB (Guobiao — Chinese National Standard), and JIS (Japanese Industrial Standard).
- Austenitic Grades: 304 (1.4301), 304L (1.4307), 316 (1.4401), 316L (1.4404), 321 (1.4541), 310S (1.4845), 316Ti (1.4571)
- Ferritic Grades: 430 (1.4006), 409 (1.4521), 441 (1.4510)
- Duplex Grades: 2205 (1.4462), 2507 (1.4501)
- Other Grades: 17-4PH (1.4542), 904L (1.4539), Alloy 625 (1.4547)
2.2 Mechanical Properties (Typical — Grade 304, Annealed Condition)
| Property | Unit | Specification |
|---|---|---|
| Tensile Strength (抗拉强度) | MPa | ≥ 520 |
| Yield Strength (屈服强度) | MPa | ≥ 205 |
| Elongation (延伸率) | % | ≥ 40 |
| Hardness (硬度) | HV | ≤ 210 |
| Density (密度) | g/cm³ | 8.00 |
| Thermal Conductivity (热导率) | W/(m·K) | 16.3 (at 100°C) |
| Modulus of Elasticity (弹性模量) | GPa | 193 |
2.3 Surface Finish Options
- No.1 Finish: Hot-rolled and annealed, with scale removed by pickling
- 2B Finish: Cold-rolled, annealed, and passivated (Bright Annealed)
- No.4 Finish: Brushed finish with uniform matte appearance
- Mirror Finish (8K): Highly polished, reflective surface
- Pickled & Passivated (酸洗钝化): Corrosion-resistant passive oxide layer restored
3. Specifications
| Parameter | Range / Options | Standard Reference |
|---|---|---|
| Outer Diameter (外径, OD) | Φ6 mm — Φ219 mm | ASTM A213 / GB/T 12771 |
| Wall Thickness (壁厚, WT) | 0.5 mm — 12.0 mm | ASTM A269 / EN 10216 |
| Coil Inner Diameter (盘管内径) | Φ400 mm — Φ600 mm | — |
| Coil Outer Diameter (盘管外径) | ≤ Φ1200 mm | — |
| Coil Length (盘管长度) | 50 m — 500 m (continuous) | — |
| Coil Weight (盘管重量) | Up to 5,000 kg per coil | — |
| Tolerance — OD (外径公差) | ±0.05 mm to ±0.5 mm | GB/T 12771 |
| Tolerance — WT (壁厚公差) | ±10% (standard) / ±5% (precision) | ASTM A213 |
| Roundness (圆度) | ≤ 1% of OD | — |
| Material Condition (材料状态) | Annealed (固溶处理), Cold Worked, Solution Heat Treated | — |
| End Form (端部形式) | Plain end, Beveled end, Threaded, Flanged | — |
4. Manufacturing Process
4.1 Process Flow
- Raw Material Preparation: Stainless steel wire rod or strip is procured, inspected, and prepared for forming. Incoming materials undergo chemical composition verification via Spectroscopy Analysis (光谱分析) and mechanical testing.
- Coil Forming / Tube Making: The strip or wire is fed through a Roll Forming (辊压成型) or ERW (Electric Resistance Welding) / Freudenberg Process line to form the tubular profile. For seamless coil tubes, Capillary Drawing (毛细管拉拔) or Piercing (穿孔) methods are employed.
- Welding (if applicable): For welded coil tubes, the longitudinal seam is fused using High-Frequency Induction Welding (高频感应焊接), followed by Internal and External Upset (内外翻边) to homogenize the weld zone.
- Heat Treatment: Solution Annealing (固溶退火) is performed at 1010–1150°C (depending on grade) followed by rapid water quenching to dissolve carbides and restore full austenitic structure and corrosion resistance.
- Pickling & Passivation (酸洗钝化): The coil tube is treated with a mixture of nitric acid and hydrofluoric acid to remove oxide scale, followed by passivation to establish a protective chromium oxide layer.
- Coiling: The finished tube is wound onto a coil mandrel at controlled tension to maintain dimensional stability. The Intelligent Overhead Bridge Crane (智能桥式起重机) assists in positioning and transferring the heavy coil bundles with precision.
- Quality Inspection: Each coil undergoes Ultrasonic Testing (UT) (超声波检测), Eddy Current Testing (ECT) (涡流检测), Hydrostatic Testing (水压试验), and visual inspection for surface defects.
- Marking & Packaging: Coils are marked with grade, heat number, dimensions, and certification information. Packaging includes protective wrapping, moisture-absorbing desiccants, and wooden or steel coil saddles.
4.2 Role of the Intelligent Overhead Bridge Crane in Production
The integration of an Intelligent Overhead Bridge Crane (智能桥式起重机) into the coil tube production line is a hallmark of modern, high-throughput manufacturing. Key functions include:
- Precision Material Handling: Automated lifting and transfer of coil bundles weighing up to 5 tonnes with sub-millimeter positioning accuracy.
- Reduced Human Intervention: Smart control systems minimize manual handling, reducing safety risks and operator fatigue.
- Real-Time Monitoring: Load sensors and PLC (Programmable Logic Controller) integration enable continuous monitoring of coil weight, suspension balance, and transfer trajectory.
- Production Line Synchronization: The crane coordinates with upstream forming and downstream inspection stations to optimize material flow and reduce idle time.
- Damage Prevention: Controlled acceleration and deceleration profiles prevent coil deformation, surface scratching, and inter-coil compression damage.
5. Applications
Stainless steel coil tubes find extensive application across multiple industries due to their corrosion resistance, mechanical strength, hygienic properties, and formability:
- Petroleum & Chemical Industry (石油化工): Heat exchangers, reactor tubes, transfer lines, and process piping systems handling aggressive media.
- Food & Beverage Processing (食品饮料): Sanitary piping, brewing equipment, dairy processing lines, and CIP (Clean-In-Place) systems.
- Pharmaceutical Industry (制药): GMP-compliant piping, bioreactor components, and sterile transfer lines.
- Energy Sector (能源): Solar thermal collectors, nuclear reactor components, and geothermal heat exchange systems.
- Automotive & Aerospace (汽车与航空): Exhaust systems, fuel lines, structural tubing, and lightweight structural components.
- Construction & Architecture (建筑): Structural supports, decorative elements, and elevator guide rails.
- Medical Equipment (医疗器械): Surgical instrument tubing, implant manufacturing, and diagnostic equipment housings.
- Downstream Tube Manufacturing: Feedstock for cold-drawn seamless tubes, precision tubes, and decorative tubes.
6. Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains rigorous quality management systems and holds the following certifications and complies with the following standards:
| Certification / Standard | Description |
|---|---|
| ISO 9001:2015 | Quality Management System certification ensuring consistent product quality |
| ISO 14001:2015 | Environmental Management System certification |
| ISO 45001:2018 | Occupational Health and Safety Management System |
| EN 10204 3.1 / 3.2 | Material Test Reports — Third-party inspection available |
| CE Marking | Conformity with European health, safety, and environmental protection standards |
| ASTM A213 / A269 / A312 | Compliance with American Society for Testing and Materials standards for seamless and welded stainless steel tubes |
| GB/T 12771 / GB/T 14976 | Compliance with Chinese National Standards for stainless steel welded and seamless tubes |
| EN 10216-5 / EN 10217-7 | Compliance with European Standards for stainless steel tubes for pressure and non-pressure applications |
| PED (Pressure Equipment Directive 2014/68/EU) | Applicable for pressure vessel and piping applications |
| 3-A Sanitary Standards | For food-grade and pharmaceutical applications |
7. Unique Selling Points
- Integrated Intelligent Production: The deployment of intelligent overhead bridge cranes in the coil tube production line ensures superior coil integrity, precise handling, and enhanced operational efficiency.
- Full Traceability: Each coil is traceable from raw material heat number through all processing stages to final delivery, supported by digital documentation and third-party inspection.
- Wide Grade Availability: Extensive range of material grades from standard austenitic to specialty alloys, meeting diverse application requirements.
- Precision Dimensional Control: Advanced forming and inspection capabilities deliver tight tolerances suitable for high-precision applications.
- Customization Capability: Flexible production parameters allow customization of dimensions, surface finish, end forms, and packaging to meet specific customer specifications.
- Comprehensive Testing: Multi-modal inspection including ultrasonic, eddy current, hydrostatic, and visual testing ensures defect-free product