400-Series Six-Coil Twisted Stainless Steel Coil Tube (Coiltube) — Wiring Conduit
Product Overview
The 400-Series Six-Coil Twisted Stainless Steel Coil Tube, manufactured by Wenzhou Jixing Metal Materials Co., Ltd (Product Catalog No. 1656), represents a next-generation flexible electrical wiring conduit engineered through an advanced six-coil helical twisting process. This product is designed specifically for cable management and electrical conduit applications where superior flexibility, mechanical strength, and corrosion resistance are simultaneously demanded. The coil tube is produced using a specialized six-coil tube twisting machine (六盘管绞机), a process that has undergone significant reform and optimization to enhance production efficiency, dimensional accuracy, and product performance consistency.
The "400-Series" designation refers to the model classification of the twisting machine used in production, indicating a processing capability for tubes within a defined diameter range optimized for standard electrical wiring conduit dimensions. The six-coil configuration provides a balanced helical structure that delivers optimal bend radius characteristics while maintaining structural integrity under compression and torsional loads.
Material and Properties
The coil tube is fabricated from high-grade austenitic stainless steel, selected for its exceptional combination of mechanical properties and corrosion resistance. The following table summarizes the key material specifications:
| Property | Specification | Standard Reference |
|---|---|---|
| Base Material | Austenitic Stainless Steel (304 / 316 / 321 grades) | ASTM A269 / ASTM A312 |
| Chemical Composition (304) | C ≤ 0.08%, Cr 18.0–20.0%, Ni 8.0–10.5%, Mn ≤ 2.0%, Si ≤ 1.0%, S ≤ 0.03% | ASTM A240 |
| Tensile Strength (Ultimate) | ≥ 520 MPa (75,400 psi) | ASTM A269 |
| Yield Strength (0.2% Offset) | ≥ 205 MPa (29,700 psi) | ASTM A269 |
| Elongation (at Break) | ≥ 40% (minimum) | ASTM A269 |
| Hardness (Rockwell B) | ≥ 70 HRB (annealed condition) | ASTM A269 |
| Corrosion Resistance | Equivalent to 304 stainless; 316 grade available for chloride-rich environments | ASTM G48 |
| Temperature Range | −196 °C to +870 °C (304); −196 °C to +870 °C (316) | ASME BPVC Section II |
| Surface Finish | Mill finish, polished, or electropolished (available upon request) | ASTM A479 |
| Magnetic Permeability | ≤ 1.05 (1000 Oe) | ASTM A968 |
Specifications
The 400-Series Six-Coil Twisted Coil Tube is available in a comprehensive range of dimensions to accommodate diverse wiring conduit and cable protection requirements. The following table details the dimensional specifications:
| Parameter | Specification / Range | Unit |
|---|---|---|
| Model Designation | 400-Series (六盘管绞机) | — |
| Outer Diameter (OD) | 8 – 50 | mm |
| Wall Thickness | 0.5 – 1.5 | mm |
| Helical Coil Diameter | Varies per OD specification | mm |
| Number of Helical Coils (Lays) | 6 (six-coil configuration) | — |
| Coil Pitch (Helix Spacing) | 3.0 – 6.0 (adjustable per application) | mm |
| Minimum Bend Radius | 1.5 × OD | — |
| Maximum Bend Radius (Repeated) | 3 × OD (without degradation) | — |
| Coil Length (per Package) | 50 – 200 | m |
| Coil Weight (typical) | 0.04 – 0.35 | kg/m |
| Electrical Resistance (at 20 °C) | ≤ 0.72 | Ω·mm²/m |
| Compressive Load Capacity | ≥ 5,000 N (per section, depending on OD) | N |
| Crush Resistance (Flattening) | No collapse up to 50% OD reduction | — |
| Fire Rating | Non-combustible; self-extinguishing | — |
| Insulation Resistance | ≥ 100 MΩ (at 500 V DC) | MΩ |
| Dimensional Tolerance (OD) | ± 0.05 mm | mm |
| Dimensional Tolerance (Wall Thickness) | ± 0.02 mm | mm |
Manufacturing Process
The production of the 400-Series Six-Coil Twisted Stainless Steel Coil Tube employs a multi-stage manufacturing workflow, each step rigorously controlled to ensure product quality and dimensional consistency. The reform of the 400-Series six-coil tube twisting machine (六盘管绞机穿线管的改革) has introduced critical process improvements that distinguish this product from conventional coil tube offerings.
Process Flow
- Raw Material Inspection and Preparation: Stainless steel strip or seamless pipe stock is received and subjected to incoming quality control, including spectroscopic analysis (OES) for chemical composition verification, dimensional gauging, and surface inspection. Material certificates (Mill Test Reports) are reviewed and archived.
- Forming and Shaping: The stainless steel stock is fed through a precision forming line where it is shaped into the required cross-sectional profile. For coil tube production, the material is formed into a helical wire or tape configuration suitable for the six-coil twisting process.
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Helical Twisting (Six-Coil Configuration): The reform-critical step involves the six-coil tube twisting machine. Six individual helical elements are simultaneously twisted together around a central core to form the coil tube structure. The reform of this machine has improved:
- Twist angle consistency, reducing helix variation from ±3° to ±1°
- Coil spacing uniformity, with pitch tolerance reduced to ±0.1 mm
- Production speed, increasing throughput by approximately 25%
- Reduction in surface scratches and mechanical damage during twisting
- Welding (if applicable): In configurations requiring a continuous helical wire, TIG (Tungsten Inert Gas) welding or laser welding is employed to create the helical wire from strip stock. Weld quality is verified through visual inspection and periodic destructive testing.
- Heat Treatment (Annealing): The twisted coil tube is subjected to solution annealing at 1050–1150 °C followed by controlled cooling to restore the full austenitic microstructure, relieve residual stresses, and achieve the required mechanical properties. This step ensures maximum corrosion resistance and ductility.
- Pickling and Passivation: Post-annealing oxide scale is removed through acid pickling (typically nitric-hydrofluoric acid blend or citric acid for environmentally conscious processing), followed by passivation treatment to restore the protective chromium oxide layer on the stainless steel surface.
- Dimensional Inspection and Quality Control: Each coil is inspected for outer diameter, wall thickness, helix pitch, and overall dimensional compliance. Non-destructive testing (NDT) methods including eddy current testing and visual inspection are applied. Sample destructive testing (tensile, bend, and corrosion tests) is performed per production lot.
- Coiling and Packaging: The finished coil tube is wound onto standardized coils (typically wooden or steel core) with protective wrapping to prevent damage during storage and transport. Each coil is labeled with product identification, batch number, material grade, and compliance documentation.
Key Process Innovations (Reform Highlights)
The reform of the 400-Series six-coil tube twisting machine has been instrumental in achieving the following advancements:
- Enhanced Precision: Implementation of CNC-controlled twisting heads with real-time feedback systems for helix geometry control
- Reduced Waste: Optimized material utilization reducing scrap rates by approximately 15% compared to pre-reform processes
- Improved Surface Quality: Precision-guided twisting rollers with hardened and polished contact surfaces minimize surface defects
- Higher Throughput: Continuous feeding mechanisms and automated coil changeover systems increase production efficiency
- Consistent Product Quality: Statistical Process Control (SPC) integration enables real-time monitoring and corrective action
Applications
The 400-Series Six-Coil Twisted Stainless Steel Coil Tube serves a wide range of industrial and commercial applications where flexible, durable, and corrosion-resistant cable protection is required:
- Electrical Wiring Conduit: Primary application for protecting electrical cables and wiring in commercial buildings, industrial facilities, and infrastructure projects. The flexible helical structure allows easy routing through complex layouts while providing mechanical protection against impact and abrasion.
- Industrial Automation: Cable protection in robotics, CNC machinery, conveyor systems, and automated production lines where frequent bending and movement of cable assemblies is required.
- Oil and Gas Industry: Corrosion-resistant cable protection in offshore platforms, refineries, and petrochemical facilities. 316-grade coil tube is recommended for chloride-containing environments.
- Marine and Shipbuilding: Cable routing and protection in marine vessels, submarines, and offshore structures where saltwater corrosion resistance is critical.
- Food and Pharmaceutical Processing: Hygienic-grade coil tube for cable protection in food processing plants, breweries, and pharmaceutical manufacturing facilities where ease of cleaning and corrosion resistance are mandatory.
- Power Generation: Cable protection in power stations, substations, and renewable energy installations (solar, wind) where environmental durability is essential.
- Transportation Infrastructure: Cable management in rail systems, airports, tunnels, and bridges where long service life and low maintenance are prioritized.
- Telecommunications: Protection of fiber optic cables and communication wiring in data centers, telecom towers, and network infrastructure.
Quality Certifications and Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains rigorous quality management systems and holds the following certifications and standards compliance for the 400-Series Six-Coil Twisted Stainless Steel Coil Tube:
| Certification / Standard | Scope of Compliance |
|---|---|
| ISO 9001:2015 | Quality Management System certification for manufacturing operations |
| ISO 14001:2015 | Environmental Management System certification |
| ISO 45001:2018 | Occupational Health and Safety Management System |
| ASTM A269 | Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing |
| ASTM A312 | Standard Specification for Seamless, Welded, and Heavy-Walled Austenitic Stainless Steel Pipes |
| GB/T 12771 | Chinese National Standard for Stainless Steel Seamless Tubes for Fluid Transport |
| JIS G3459 | Japanese Industrial Standard for Stainless Steel Tubes |
| EN 10217 | European Standard for Non-Alloy and Alloy Steel Tubes for Mechanical and Technical Purposes |
| CE Marking | Conformity with European health, safety, and environmental protection standards |
| RoHS Compliance | Restriction of Hazardous Substances in electrical/electronic equipment applications |
Testing and Verification Protocol
- Chemical Analysis: Optical Emission Spectroscopy (OES) and wet chemical analysis for every production lot to verify compliance with ASTM A240 chemical composition requirements.
- Mechanical Testing: Tensile testing (ASTM A370), hardness testing (ASTM A956), and bend testing performed per heat lot.
- Dimensional Inspection: Full-length ultrasonic thickness gauging, OD micrometer measurement at regular intervals, and helix pitch verification using calibrated gauge fixtures.
- Corrosion Testing: Salt spray testing (ASTM B117, 1000-hour minimum), intergranular corrosion testing (ASTM A262 Practice E), and pitting corrosion testing (ASTM G48) for 316-grade products.
- Non-Destructive Testing (NDT): Eddy current testing for seam weld integrity, visual inspection of all surfaces, and dye penetrant testing for surface discontinuities.
- Flame and Fire Testing: Verification of non-combustibility and self-extinguishing properties per applicable fire safety standards.
- Electrical Properties: Resistance to ground and insulation resistance testing to verify electrical performance specifications.