Stainless Steel Coil Tube (Coiltube) — Product Technical Specification
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.
Product Reference No.: 869
Classification: Literature Study / Technical Reference
Product Overview
The Stainless Steel Coil Tube (Coiltube) is a precision-engineered tubular product manufactured in continuous coil form, designed for applications requiring flexible routing, compact installation, and high resistance to corrosion. As a core component in the modular installation systems for commercial vehicle chassis pipeline harnesses, the coil tube serves as a critical conduit for hydraulic, pneumatic, and fluid transfer systems within bus and heavy-duty vehicle architectures.
This product is manufactured to meet the rigorous demands of automotive-grade applications, where dimensional accuracy, mechanical integrity, and long-term reliability are paramount. The coil configuration enables efficient storage, transportation, and on-site deployment, reducing installation labor and material waste during modular harness assembly.
Material & Properties
Base Material Composition
- Grade Options: SUS304 (AISI 304), SUS316 (AISI 316), SUS321 (AISI 321), SUS304L (AISI 304L)
- Chromium (Cr): 18.0%–20.0%
- Nickel (Ni): 8.0%–10.5%
- Molybdenum (Mo): Up to 2.5% (for 316-grade variants)
- Titanium (Ti): Up to 0.70% (for 321-grade variants)
- Carbon (C): ≤ 0.08% (standard) / ≤ 0.03% (low-carbon variants)
Mechanical Properties
- Tensile Strength: ≥ 515 MPa (annealed condition)
- Yield Strength (0.2% offset): ≥ 205 MPa
- Elongation (at break): ≥ 40%
- Hardness (annealed): ≤ 92 HRB
- Impact Resistance: Excellent at ambient and sub-zero temperatures (down to −196°C for cryogenic applications)
Corrosion Resistance
- Pitting Resistance (PREN): 18–26 (depending on grade)
- Intergranular Corrosion Resistance: Verified per ASTM A240 standards
- Atmospheric Corrosion: Superior resistance in industrial, coastal, and agricultural environments
- Chemical Resistance: Compatible with hydraulic fluids, compressed air systems, and moderate acids
Specifications
| Parameter | Specification |
|---|---|
| Outer Diameter (OD) | 6 mm – 51 mm (custom sizes available) |
| Wall Thickness | 0.5 mm – 3.0 mm |
| OD Tolerance | ± 0.1 mm (standard); ± 0.05 mm (precision grade) |
| Wall Thickness Tolerance | ± 10% of nominal |
| Coil Length | 50 m – 500 m per coil (configurable) |
| Coil Inner Diameter (ID) | 300 mm / 500 mm / 600 mm |
| Bending Radius (minimum) | 3× OD (without mandrel); 1.5× OD (with mandrel) |
| Surface Finish | No. 1 Annealed / 2B / BA (Bright Annealed) / Electropolished (Ra ≤ 0.4 μm) |
| End Condition | Open (as-rolled) / Beveled / Crimped |
| Standard Reference | ASTM A213 / ASTM A269 / EN 10216-5 / GB/T 12771 |
| Heat Treatment | Fully annealed and pickled; optional solution annealing at 1050°C ± 30°C |
| Operating Temperature Range | −196°C to +870°C (grade-dependent) |
| Maximum Working Pressure | Up to 10 MPa (depending on OD and wall thickness) |
Manufacturing Process
Process Flow
- Raw Material Selection: Virgin stainless steel strip or seamless tube billet sourced from certified mills, verified for chemical composition via spectroscopic analysis.
- Coil Forming / Seamless Tube Drawing: Cold-rolled strip is precision-wound into coil tube form, or seamless tubes are drawn to required OD and wall thickness specifications.
- Welding (for welded variants): TIG (Tungsten Inert Gas) welding with internal gas shielding (argon) to ensure weld integrity and prevent oxidation.
- Solution Annealing: Heating to 1050°C ± 30°C followed by controlled cooling to restore full annealed microstructure and relieve residual stresses.
- Pickling & Passivation: Immersion in mixed acid bath (nitric + hydrofluoric acid) to remove scale, followed by passivation treatment to restore the protective chromium oxide layer.
- Dimensional Inspection: Automated optical measurement of OD, wall thickness, and roundness at intervals of ≤ 1 meter.
- Coil Winding & Packaging: Precision winding onto designated coil cores with protective wrapping (VCI film, kraft paper, and shrink-wrapped outer packaging).
Key Process Controls for Modular Installation Applications
For applications in bus chassis pipeline harness modular installation, the coil tube undergoes additional quality assurance steps:
- Hydrostatic Pressure Testing: Each batch tested at 1.5× maximum working pressure for a minimum of 10 seconds to verify leak-tightness.
- Visual Surface Inspection: 100% inspection for surface defects, weld seams, and oxide inclusions.
- Dimensional Consistency Verification: Ensures compatibility with modular connector fittings and clamp systems used in harness assembly.
Applications
Primary Application Domain: Commercial Vehicle Chassis Systems
The coil tube is specifically engineered for integration into modular pipeline harness systems on bus and commercial vehicle chassis platforms. Key applications include:
- Air Brake Systems: Conveyance of compressed air in pneumatic braking circuits
- Hydraulic Steering Systems: High-pressure fluid transfer for power steering actuation
- Fuel System Piping: Fuel delivery lines requiring corrosion resistance and leak prevention
- Exhaust Gas Recirculation (EGR) Lines: High-temperature resistant fluid routing
- Air Conditioning & HVAC Piping: Refrigerant and coolant transfer in passenger compartment systems
Extended Applications
- Automotive exhaust systems and turbocharger piping
- Medical equipment fluid transfer systems
- Food processing and pharmaceutical equipment
- Industrial gas and chemical transport
- Solar thermal energy systems
- Instrumentation and analytical laboratory equipment
Quality Certifications & Compliance
Product Certifications
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System
- ISO/TS 22163 — Automotive Production Part Approval Process (IATF 16949 aligned)
- EN 10204 3.1 — Material Test Certificate (Third-Party Inspection Available)
- CE Marking — European Conformity for pressure equipment directives
Applicable Standards
- ASTM A213 — Specification for Seamless and Welded Austenitic Stainless Steel Tubing
- ASTM A269 — Specification for Seamless and Welded Austenitic Stainless Steel Tubing for Chemical and General Industrial Applications
- EN 10216-5 — Steel Tubes for Mechanical and Technical Purposes — Non-Heat-Resistant Stainless Steel Tubes
- GB/T 12771 — Stainless Steel Seamless Tubes for General Purposes (Chinese National Standard)
- JIS G3446 — Stainless Steel Seamless Tubes (Japanese Industrial Standard)
Testing & Inspection Protocols
- Chemical analysis by optical emission spectrometry (OES)
- Mechanical testing per ASTM E8/E8M (tensile) and ASTM A370 (impact)
- Corrosion testing: Salt spray test (ASTM B117, 1000 hours minimum), intergranular corrosion (ASTM A923 Method 1A)
- Dimensional inspection via ultrasonic wall thickness gauging and laser diameter measurement
- Full traceability from heat number to finished coil via barcode-based quality documentation system
Unique Selling Points
- Modular Installation Compatibility: Optimized dimensional tolerances and surface finishes for seamless integration with modular clamp-and-connector systems in vehicle chassis harness assembly, reducing installation time by up to 40% compared to traditional cut-and-weld methods.
- Superior Corrosion Longevity: Multi-grade options (304/316/321) provide tailored corrosion resistance profiles for diverse operating environments, extending service life beyond 15 years under normal conditions.
- Flexible Coil Configuration: Continuous coil format enables on-demand cutting and routing, minimizing material waste and enabling complex 3D path layouts inherent in chassis harness design.
- Automotive-Grade Reliability: Manufactured to IATF 16949-aligned processes with full batch traceability, ensuring consistent quality for safety-critical vehicle systems.
- Thermal & Mechanical Versatility: Operating range from cryogenic (−196°C) to elevated temperatures (870°C) with no loss of ductility, making the product suitable for extreme environmental conditions encountered in commercial vehicle applications.
Conclusion
The Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd. represents a high-performance, precision-manufactured tubular product purpose-built for demanding automotive and industrial applications. Its compliance with international standards, combined with the manufacturing expertise and quality assurance infrastructure of the producer, makes it an ideal solution for modular chassis pipeline harness systems and a wide range of other engineering applications requiring corrosion-resistant, mechanically robust fluid conveyance solutions.