Stainless Steel Seamless Coil Tube — 100% Eddy Current Tested
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. manufactures high-performance stainless steel seamless coil tubes designed for demanding industrial applications where material integrity, dimensional precision, and corrosion resistance are paramount. Every coil tube produced undergoes a rigorous 100% online eddy current testing (ET) process using through-type coil sensors, ensuring that only defect-free products reach the end user. This comprehensive quality assurance protocol distinguishes Jixing coil tubes as a reliable choice for critical infrastructure, energy, chemical processing, and food-grade applications worldwide.
Material & Properties
Jixing stainless steel coil tubes are available in a broad range of austenitic, duplex, and specialty alloy grades, including but not limited to:
- Austenitic Grades: 304, 304L, 316, 316L, 321, 310S, 347
- Duplex Grades: 2205 (UNS S31803), 2507 (UNS S32750)
- Specialty Alloys: Inconel 625, Hastelloy C-276, Alloy 825
These materials deliver superior resistance to oxidation, pitting, crevice corrosion, and intergranular attack across a wide temperature range. The seamless construction ensures uniform microstructure without the weld-line vulnerabilities inherent to welded alternatives, providing consistent mechanical properties throughout the tube cross-section.
Specifications
| Parameter | Specification |
|---|---|
| Outer Diameter (OD) | 6.0 mm – 114.3 mm (1/4" – 4-1/2") |
| Wall Thickness | 0.5 mm – 6.0 mm |
| Coil Length | Custom (typically 50 m – 300 m per coil) |
| Tolerance — OD | ±0.05 mm (precision grades available) |
| Tolerance — Wall | ±10% of nominal |
| Surface Finish | Bright annealed, pickled & passivated, or custom |
| Manufacturing Standard | ASTM A213, ASTM A269, EN 10216-5, GB/T 14976 |
| NDT Coverage | 100% online eddy current inspection (through-type coil) |
| NDT Throughput Speed | Up to 60 m/min |
Manufacturing Process
Step 1 — Billet Preparation
High-purity stainless steel billets are sourced from certified mills, inspected for chemical composition, and heated to controlled piercing temperatures to achieve optimal plasticity.
Step 2 — Hot Piercing & Rolling
Continuous hot-piercing technology produces seamless pipe blanks with tight dimensional control. Multi-stand rolling reduces the tube to near-final dimensions while maintaining uniform wall thickness.
Step 3 — Cold Drawing & Sizing
The tube undergoes cold drawing through precision dies to achieve exact OD, wall thickness, and straightness tolerances. This step also enhances surface finish and mechanical strength.
Step 4 — Annealing & Pickling
Post-draw annealing relieves residual stresses and restores full austenitic grain structure. Subsequent pickling and passivation remove scale and contaminants, establishing a protective chromium oxide film.
Step 5 — Coil Winding
Finished tubes are wound into coils on precision-wound spools, minimizing mechanical deformation and ensuring consistent handling during downstream fabrication.
Step 6 — 100% Online Eddy Current Testing (ET)
Every coil tube passes through a fully automated through-type eddy current inspection system operating at speeds up to 60 meters per minute. The through-type coil sensor induces electromagnetic eddy currents within the tube wall, detecting:
- Surface and near-surface cracks — including fatigue cracks, stress corrosion cracks, and thermal fatigue fractures
- Laps and folds — manufacturing defects from piercing or rolling that compromise structural integrity
- Inclusions — non-metallic impurities (sulfides, oxides, slag) that can act as corrosion initiation sites
The 100% coverage ensures that no tube segment escapes inspection. Any coil containing a detected defect is flagged, quarantined, and either reworked or rejected — guaranteeing zero-defect delivery.
Quality Certifications
- ISO 9001:2015 — Quality Management System
- ISO 14001 — Environmental Management System
- ASME Certificate of Compliance (U Stamp) — for pressure vessel and piping applications
- EN 10204 3.1 / 3.2 Test Reports — third-party verified material certification
- Mill Test Reports (MTR) — full chemical analysis and mechanical property documentation for each heat
- NDT Procedure Approval — ET procedures qualified per ASTM E332 and ASTM E1444
Applications
Jixing stainless steel coil tubes are trusted in a wide spectrum of high-reliability applications:
- Heat Exchangers & Condensers — boiler tubes, air-cooled heat exchangers, and process coolers
- Chemical & Petrochemical Processing — reactor tubing, distillation columns, and heat transfer systems
- Power Generation — supercritical boiler tubes, steam generators, and nuclear-grade applications
- Food & Beverage Industry — sanitary-grade tubing for dairy, brewery, and pharmaceutical processing
- Automotive & Aerospace — exhaust systems, fuel lines, and hydraulic tubing
- Water Treatment & Desalination — RO membrane housings and high-pressure piping
Unique Selling Points
Uncompromising Quality Assurance: The industry-leading 100% online eddy current inspection at 60 m/min throughput provides both speed and sensitivity — detecting even micro-scale surface and near-surface defects that traditional spot-check methods would miss. This ensures every meter of coil tube delivered is free from cracks, laps, and inclusions.
- Full Traceability: Every coil is traceable from raw material heat number through final inspection, with complete digital records available upon request.
- High Throughput, Low Defect Rate: The combination of modern cold-drawing technology and automated ET inspection yields exceptionally low rejection rates while maintaining 100% inspection coverage.
- Customization Capability: Non-standard ODs, wall thicknesses, surface finishes, and coil configurations are available to meet specific engineering requirements.
- Global Compliance: Products manufactured to meet international standards (ASTM, EN, GB) with full documentation support for regulatory and project-specific requirements.
Conclusion
Wenzhou Jixing Metal Materials Co., Ltd. delivers stainless steel coil tubes that combine metallurgical excellence, precision manufacturing, and uncompromising quality control. The 100% through-type eddy current inspection at speeds up to 60 m/min represents a best-in-class quality gate that protects end users from field failures, unplanned maintenance, and costly downtime. Whether for demanding chemical service, critical power generation, or sanitary food processing, Jixing coil tubes provide the reliability and performance that mission-critical applications demand.