Stainless Steel Coil Tube — Continuous Coiled Tubing Product
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) is a continuous-length tubing product formed into a compact coil configuration, designed for seamless downstream processing including straightening, cutting, forming, and welding. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd, this product represents a high-precision, high-efficiency solution that eliminates the need for individual bar handling and reduces material waste significantly. The coil tube format is particularly advantageous for automated production lines requiring uninterrupted material feed, offering superior dimensional consistency and surface quality compared to conventional cut-to-length tubing.
The production methodology draws upon advanced continuous tube-forming and rolling technologies, incorporating lessons from high-precision coil tube manufacturing practices — including those developed for specialty alloy tubing — to achieve tight tolerances, uniform wall thickness, and excellent mechanical performance across the entire coil length.
2. Material & Properties
Stainless steel coil tubes are manufactured from austenitic, ferritic, and duplex stainless steel grades, selected based on end-use requirements for corrosion resistance, mechanical strength, and formability.
- Austenitic Grades (奥氏体不锈钢): AISI 304, 304L, 316, 316L, 321, 310S — Excellent corrosion resistance, good weldability, non-magnetic
- Ferritic Grades (铁素体不锈钢): 430, 409, 446 — Improved thermal conductivity, lower cost, moderate corrosion resistance
- Duplex Grades (双相不锈钢): 2205, 2507 — High yield strength, superior resistance to chloride stress corrosion cracking
- Super-Austenitic Grades (超级奥氏体不锈钢): 904L, AL-6XN — Exceptional resistance to aggressive chemical environments
Key Mechanical Properties (Typical)
| Property | AISI 304/304L | AISI 316/316L | 2205 Duplex |
|---|---|---|---|
| Tensile Strength (MPa) | ≥ 520 | ≥ 515 | ≥ 450 |
| Yield Strength (0.2% Offset, MPa) | ≥ 205 | ≥ 205 | ≥ 450 |
| Elongation (%) | ≥ 40 | ≥ 40 | ≥ 25 |
| Hardness (HB) | ≤ 217 | ≤ 217 | ≤ 321 |
| Operating Temperature Range (°C) | -196 to +870 | -196 to +870 | -50 to +300 |
3. Specifications
| Parameter | Specification |
|---|---|
| Outer Diameter (OD) | Φ6.0 mm – Φ108 mm |
| Wall Thickness (WT) | 0.3 mm – 6.0 mm |
| OD Tolerance | ±0.05 mm (precision grade); ±0.1 mm (standard grade) |
| Wall Thickness Tolerance | ±0.03 mm (precision grade); ±0.05 mm (standard grade) |
| Roundness | ≤ 0.02 mm |
| Coil Weight | 500 kg – 2,500 kg (configurable) |
| Coil Inner Diameter | Φ150 mm / Φ200 mm / Φ300 mm (customer-specified) |
| Surface Finish | BA (Bright Annealed), No. 4 Brushed, Mirror (Ra ≤ 0.1 μm), 2B |
| End Condition | Plain, Beveled, Threaded, or Flanged |
| Delivery Condition | Annealed (Solution Annealed), Cold Worked (1/4-HW, 1/2-HW, Full-Hard) |
| Applicable Standards | ASTM A213, ASTM A269, GB/T 12771, GB/T 13296, EN 10217, JIS G3459 |
4. Manufacturing Process
The production of stainless steel coil tubes follows a rigorously controlled multi-stage process ensuring dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Preparation (原材料准备): Selection and verification of certified stainless steel wire rod or strip from approved mills, with full chemical composition and mechanical property verification.
- Continuous Forming (连续成型): High-precision forming rolls shape the material into seamless tube geometry through a multi-stand rolling or extrusion process, maintaining tight dimensional control throughout the forming operation.
- In-Line Annealing (在线退火): Continuous annealing in a protective atmosphere (argon or endothermic gas) to relieve cold-work stresses, restore ductility, and achieve the required grain structure. Temperature profiles are precisely controlled to prevent oxidation and ensure uniform microstructure.
- Precision Sizing (精整定径): Multi-stand sizing rolls achieve final dimensional tolerances with sub-0.05 mm accuracy, ensuring roundness and straightness within specification limits.
- Pickling & Passivation (酸洗钝化): Removal of any surface scale or discoloration through controlled acid pickling, followed by passivation treatment to restore the protective chromium oxide layer and enhance corrosion resistance.
- Surface Finishing (表面处理): Optional polishing, brushing, or mirror finishing operations to achieve specified surface roughness values (Ra) for aesthetic or functional requirements.
- Non-Destructive Testing (无损检测): Eddy current testing (ECT), ultrasonic testing (UT), and hydrostatic pressure testing to verify internal and external quality, confirming freedom from cracks, laminations, and porosity.
- Coiling & Packaging (卷取包装): Precision coiling at controlled tension to prevent deformation, followed by protective wrapping (VCI paper, plastic film, wooden spools) for shipping and storage.
5. Applications
Stainless steel coil tubes serve a wide spectrum of industrial applications, leveraging their combination of corrosion resistance, formability, and mechanical strength:
- Automotive Industry (汽车工业): Fuel lines, brake lines, exhaust system components, heat exchanger tubes, fuel cell components
- Medical Devices (医疗器械): Endoscope tubing, surgical instrument shafts, dialysis equipment, implant-grade tubing
- Food & Beverage Processing (食品加工): Hygienic piping systems, heat exchangers, CIP (Clean-in-Place) compatible tubing
- Petrochemical & Oil/Gas (石油化工): Process piping, heat exchanger tubes, condensate collection lines, offshore platforms
- Construction & Architectural (建筑与装饰): Handrails, structural tubing, decorative elements, ventilation ducts
- Electronics & Semiconductor (电子与半导体): Precision instrument tubing, vacuum system components, gas delivery lines
- Energy Sector (能源行业): Solar thermal collectors, wind turbine components, nuclear reactor instrumentation tubing
6. Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management system ensuring full traceability and compliance with international standards:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001 — Environmental Management System
- ISO/TS 22163 — Automotive quality management (IATF 16949 aligned)
- EN 10204 3.1 — Manufacturer's Test Report certification for all shipments
- CE Marking — European Conformity for pressure equipment and construction applications
- PED 2014/68/EU — Pressure Equipment Directive compliance
- Material Traceability: Full heat-number traceability from mill certificate through final delivery, including PMI (Positive Material Identification) verification
7. Unique Selling Points
- Ultra-Precision Dimensional Control: Achieving tolerances as tight as ±0.03 mm on wall thickness, enabling direct use in precision manufacturing without secondary machining.
- Continuous Production Efficiency: The coil format eliminates cut-off losses (typically 3–5% reduction in material waste) and enables fully automated downstream processing.
- Superior Surface Quality: Bright annealed surfaces with Ra values as low as 0.1 μm, reducing the need for post-processing in decorative and hygienic applications.
- Wide Grade Availability: Stocked inventory across major austenitic, ferritic, and duplex grades with rapid turnaround for custom specifications.
- Full Traceability & Compliance: Complete documentation package with every shipment, meeting the most stringent regulatory requirements in medical, aerospace, and nuclear industries.
- Custom Configuration: Flexible coil weights, inner diameters, and end conditions tailored to customer-specific production line requirements.
8. Technical Notes
Customers are advised to specify the following parameters when placing orders to ensure optimal product performance:
- Exact grade designation and delivery condition (annealed or cold-worked)
- Required surface finish and maximum permissible Ra value
- Preferred coil inner diameter and maximum coil weight for handling compatibility
- Required test certifications (EN 10204 3.1, 3.2, or third-party inspection)
- Special requirements for end preparation, marking, or bundling
All products are manufactured under strict adherence to applicable international standards and are subject to 100% inspection prior to dispatch. Wenzhou Jixing Metal Materials Co., Ltd provides technical support and application engineering assistance to ensure optimal material selection for each customer's specific requirements.