Stainless Steel Coil Tube (Coiltube) — Technical Specification
Product Overview
The Stainless Steel Coil Tube (Coiltube) is a continuously formed tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. (Catalog No. 1664). Unlike conventional straight-length seamless or welded pipes, coil tubes are produced in a continuous helical winding configuration, offering significant advantages in material utilization, transportation efficiency, and downstream processing flexibility. This product is engineered to meet rigorous industrial standards and is suitable for a wide range of applications where corrosion resistance, structural integrity, and thermal stability are paramount.
The coil tube format eliminates the need for butt-welding or threading multiple pipe sections, reducing labor costs and minimizing potential leak points. The continuous nature of the coil allows for automated processing in downstream operations such as cutting, bending, forming, and welding, making it ideal for high-volume manufacturing environments.
Material & Properties
Stainless steel coil tubes are fabricated from austenitic and duplex stainless steel grades, selected to deliver optimal combinations of corrosion resistance, mechanical strength, and formability. The following material grades are typically available:
- Austenitic Grades: AISI 304 (UNS S30400), AISI 316 (UNS S31600), AISI 316L (UNS S31603), AISI 321 (UNS S32100), AISI 347 (UNS S34700)
- Super Austenitic Grades: Alloy 20, Alloy 6, 904L (UNS N08904)
- Duplex Grades: 2205 (UNS S32205), 2507 (UNS S32750)
- Precipitation-Hardening Grades: 17-4PH (UNS S17400)
Key Material Properties
- Corrosion Resistance: Excellent resistance to atmospheric, chemical, and intergranular corrosion due to chromium (Cr) content ≥ 10.5% and, in higher grades, the addition of molybdenum (Mo) and niobium (Nb)
- Mechanical Strength: Tensile strength ranging from 515 MPa (304) to 550 MPa (316L); yield strength ≥ 205 MPa
- Temperature Range: Service temperatures from cryogenic (-196°C) to +870°C (oxidation resistance)
- Formability: High ductility enabling cold bending, deep drawing, and expansion without cracking
- Hygienic Surface: Available in sanitary (Ra ≤ 0.4 μm) and industrial (Ra ≤ 1.6 μm) finishes
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Product Code | 1664 |
| Manufacturer | Wenzhou Jixing Metal Materials Co., Ltd. |
| Outer Diameter (OD) | 6.0 mm – 108.0 mm (customizable) |
| Wall Thickness | 0.5 mm – 6.0 mm |
| Coil Length | Continuous (typically 500 m – 2000 m per coil) |
| Coil Inner Diameter (ID) | 300 mm – 600 mm (adjustable for downstream equipment) |
| Surface Finish | No. 1, 2B, BA (Bright Annealed), Electropolished (Ra ≤ 0.25 μm), Pickled & Passivated |
| Manufacturing Method | ERW (Electric Resistance Welding), Seamless, Laser Welding |
| Applicable Standards | ASTM A213, ASTM A269, ASTM A554, EN 10216-5, GB/T 12771, JIS G3459 |
| Material Grades | 304, 304L, 316, 316L, 321, 347, 2205, 2507, 904L, Alloy 6, Alloy 20 |
| Welding Method | Continuous ERW with internal/external grinding; laser welding for thin-wall precision |
| Heat Treatment | Solution Annealing (1050°C – 1150°C) followed by water quenching |
| Packaging | Wooden crate with moisture-proof wrapping; coil secured with steel strapping |
| Minimum Order Quantity | 1 coil (negotiable based on grade and specification) |
Manufacturing Process
The production of stainless steel coil tubes follows a rigorously controlled multi-stage process to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Procurement: High-purity stainless steel strip (cold-rolled) is sourced from certified mills and subjected to incoming inspection for chemical composition, mechanical properties, and surface quality.
- Coiling & Straightening: The strip is precisely unwound and fed through straightening rollers to eliminate residual curvature and ensure uniform flatness prior to forming.
- Tube Forming (Roll Forming): The flat strip passes through a series of progressively shaped rollers that gradually bend the material into a circular cross-section. This cold-forming process preserves the metallurgical structure while achieving tight dimensional tolerances.
- Welding: The formed tube is welded along the longitudinal seam using Electric Resistance Welding (ERW) or laser welding technology. ERW utilizes high-frequency current to generate localized heat at the seam, producing a strong, narrow weld bead. Laser welding offers superior precision for thin-wall applications with minimal heat-affected zone (HAZ).
- Weld Bead Grinding: The internal and external weld beads are ground flush to achieve a smooth, continuous surface. This step is critical for applications requiring fluid flow efficiency and hygienic standards.
- Heat Treatment (Solution Annealing): The welded tube is subjected to solution annealing at 1050°C – 1150°C followed by rapid water quenching. This eliminates welding-induced residual stresses, restores full corrosion resistance, and homogenizes the microstructure.
- Pickling & Passivation: The annealed tube undergoes acid pickling to remove oxide scale, followed by passivation treatment (using nitric or citric acid) to restore and enhance the protective chromium oxide layer on the surface.
- Dimensional Inspection & Testing: Each coil undergoes comprehensive quality verification including ultrasonic testing (UT), hydrostatic pressure testing (typically 1.5× working pressure), dimensional measurement (OD, wall thickness, straightness), and visual surface inspection.
- Coiling & Packaging: The finished tube is wound into a compact coil on a core, secured with steel strapping, wrapped in moisture-proof material, and packed in export-grade wooden crates.
Applications
Stainless steel coil tubes find extensive use across multiple industries due to their corrosion resistance, structural reliability, and hygienic properties:
- Food & Beverage Industry: Sanitary processing lines, dairy equipment, brewing systems, and food-grade piping where hygienic surface finishes (Ra ≤ 0.25 μm) are mandated by FDA and 3-A standards.
- Pharmaceutical & Biotechnology: Clean-in-place (CIP) and sterilize-in-place (SIP) systems, bioreactor piping, and GMP-compliant process lines.
- Chemical Processing: Handling of aggressive chemicals, acids, and corrosive media; reactor coils, heat exchangers, and transfer lines.
- Oil & Gas: Downstream processing equipment, desulfurization units, and pipelines exposed to sulfide stress cracking environments.
- Marine & Offshore: Seawater cooling systems, ballast water treatment, and subsea production equipment.
- Medical Devices: Tubular components for surgical instruments, dialysis equipment, and implant manufacturing.
- Automotive & Aerospace: Exhaust systems, fuel lines, and high-performance structural tubing.
- Construction & Architectural: Decorative railings, structural supports, and facade elements.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework to ensure product conformity and traceability:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001:2015 — Environmental Management System
- EN 10204 3.1 — Material Test Reports (MTR) issued per batch
- CE Marking — Compliance with European Pressure Equipment Directive (PED 2014/68/EU)
- NSF/ANSI 61 — Drinking water system components certification (available on request)
- 3-A Sanitary Standards — Food processing equipment compliance
- ASME BPE — Bioprocessing Equipment guidelines compliance (for pharmaceutical applications)
- Mill Test Certificates (MTC) — Chemical composition and mechanical property verification per EN 10204
Unique Selling Points
- Continuous Coil Format: Eliminates joint leakage risks and reduces downstream processing time by up to 40% compared to straight-length pipe sections.
- Wide Grade Availability: From standard 304/316L to super-austenitic and duplex grades, meeting the most demanding corrosion and mechanical requirements.
- Precision Manufacturing: Laser welding capability for thin-wall tubes (≤ 1.0 mm) with weld widths as narrow as 0.3 mm.
- Custom Surface Finishes: From industrial pickled to electropolished sanitary finishes (Ra ≤ 0.25 μm), tailored to application-specific requirements.
- Full Traceability: Each coil is accompanied by a complete batch traceability package including MTC, dimensional inspection reports, and hydrostatic test records.
- Competitive Lead Times: Standard grades available from stock; custom specifications delivered within 15–25 working days.
Technical Notes
Note on Tube-Dwelling Adaptability: The smooth internal surface finish and precise dimensional tolerances of coil tubes are particularly advantageous in applications involving internal fluid dynamics and biological compatibility. Studies on tube-dwelling organism adaptation (e.g., Enhydra and tube-forming polychaete behaviors) demonstrate that surface roughness and internal geometry significantly influence biofilm formation and flow characteristics. Wenzhou Jixing's electropolished and sanitary-grade coil tubes minimize biofilm attachment surfaces, reducing maintenance frequency and ensuring long-term hygienic performance in critical process applications.
Ordering Information
For detailed quotations, material test reports, or custom specification inquiries, contact Wenzhou Jixing Metal Materials Co., Ltd. directly. Specify the following parameters when placing an order:
- Material grade (e.g., 316L, 2205, 904L)
- Outer diameter and wall thickness (mm)
- Required surface finish
- Applicable standard (ASTM, EN, GB, JIS)
- Coil length and packaging requirements
- Quantity and delivery destination