Welded Stainless Steel Pressure Tube Coil — EN 10217-7
Wenzhou Jixing Metal Materials Co., Ltd. offers a premium range of welded stainless steel coil tubes manufactured in strict accordance with EN 10217-7, the European standard governing welded austenitic stainless steel tubes for pressure applications. These coil tubes are engineered for demanding service environments where mechanical integrity, corrosion resistance, and pressure containment are paramount. Delivered in continuous coil form, they provide maximum material utilization, reduced cutting waste, and superior downstream processing efficiency for fabricators and end-users across Europe and beyond.
Product Overview
EN 10217-7 defines the technical delivery conditions for welded stainless steel tubes intended for use in pressure systems. The standard covers austenitic grades including 1.4301 (304), 1.4401 (316), 1.4509 (316L), 1.4541 (321), and other specified compositions, ensuring that every tube meets rigorous requirements for chemical composition, mechanical properties, dimensional tolerances, and surface quality. Our coil tubes are produced using advanced automatic orbital welding technology, followed by precise post-weld heat treatment to achieve the specified microstructural condition and mechanical performance.
Material & Properties
- Material Grades: 1.4301 (304), 1.4401 (316), 1.4509 (316L), 1.4541 (321), 1.4571 (347), 1.4462 (904L), and additional grades available upon request
- Microstructure: Fully austenitic, non-magnetic, solution-annealed condition (typically Condition A per EN 10217-7)
- Corrosion Resistance: Excellent resistance to atmospheric, chemical, and intergranular corrosion; high-temperature oxidation resistance up to specified limits
- Mechanical Properties: Yield strength (Rp0.2) ≥ 205 MPa; tensile strength (Rm) 520–750 MPa; elongation (A5) ≥ 35% (typical for 1.4301 in solution-annealed condition)
- Operating Temperature Range: −196 °C to +600 °C (grade-dependent)
- Weldability: Superior weldability with minimal risk of sensitization in low-carbon grades (L-suffix)
Specifications
| Parameter | Specification |
|---|---|
| Standard | EN 10217-7 (European — Welded Pressure Tubes) |
| Manufacturing Method | Automatically Welded (AW) — longitudinal weld |
| Delivery Form | Continuous Coil (Coiltube) |
| Outer Diameter (OD) | 6 mm – 219 mm (custom sizes available) |
| Wall Thickness | 0.5 mm – 6.0 mm (custom thicknesses available) |
| Surface Finish | 2B, BA (Bright Annealed), Pickled & Passivated |
| Heat Treatment Condition | Solution Annealed (Condition A); Stabilized (Condition S) for 321/347 grades |
| Weld Seam NDT | 100% Radiographic Testing (RT) or Ultrasonic Testing (UT) per EN 10217-7 Class A/B |
| Dimensional Tolerances | OD ±0.1 mm; Wall Thickness ±0.05 mm (tight tolerance available) |
| Coil Weight | 500 kg – 3,000 kg per coil (standard); up to 5,000 kg upon request |
| End Protection | Plastic end caps, protective wrapping, and moisture-absorbent desiccant |
| Material Certificates | EN 10204 3.1 / 3.2 (third-party inspection available) |
Manufacturing Process
The production of EN 10217-7 compliant welded stainless steel coil tubes at Wenzhou Jixing Metal Materials follows a rigorously controlled multi-stage process:
- Strip Preparation: Cold-rolled stainless steel strip is inspected for surface quality, dimensional accuracy, and chemical composition before slitting to the required width.
- Forming: Precision roll-forming machinery shapes the strip into the target tube diameter with controlled springback compensation for dimensional accuracy.
- Welding: Automatic orbital TIG (GTAW) welding is performed with high-purity argon shielding gas, ensuring a clean, consistent, and defect-free longitudinal weld seam.
- Post-Weld Heat Treatment: Tubes are solution-annealed at temperatures between 1050 °C and 1100 °C, followed by rapid water quenching to achieve a fully austenitic, solution-annealed microstructure (Condition A). For stabilized grades, an additional stabilization heat treatment is applied.
- Non-Destructive Testing (NDT): 100% of weld seams undergo radiographic testing (RT) or ultrasonic testing (UT) to detect internal defects such as lack of fusion, porosity, or cracks. Testing is performed to EN 10217-7 Class A or Class B acceptance criteria, depending on application severity.
- Hydrostatic / Pressure Testing: Every tube is subjected to hydrostatic pressure testing to verify pressure integrity and eliminate any potential leaks.
- Surface Treatment: Pickling and passivation remove weld discoloration and mill scale, restoring full corrosion resistance and achieving the specified surface finish.
- Coiling & Packaging: Tubes are coiled on precision-driven coiling stands to maintain dimensional stability. Each coil is wrapped in protective film, padded, and secured for safe transport.
Applications
EN 10217-7 welded stainless steel coil tubes are designed for pressure-bearing applications across multiple industries:
- Pressure Vessels & Piping Systems: Steam systems, hydraulic circuits, pneumatic lines, and process piping in chemical and petrochemical plants
- Heat Exchangers: Tube bundles for shell-and-tube, plate-fin, and air-cooled heat exchangers in power generation and HVAC
- Food & Beverage Processing: Sanitary-grade piping and equipment components requiring high cleanliness and corrosion resistance
- Pharmaceutical & Biotechnology: CIP/SIP-compatible process lines, reactor coils, and transfer tubing
- Automotive & Aerospace: Fuel lines, exhaust components, and high-temperature structural tubing
- Energy Sector: Solar thermal collectors, geothermal systems, and nuclear auxiliary piping
- Medical Devices: Tubing for surgical instruments, dialysis machines, and laboratory apparatus
Quality Certifications & Compliance
Every batch of EN 10217-7 welded stainless steel coil tube is backed by comprehensive quality documentation and third-party verification:
- Standard Compliance: Full compliance with EN 10217-7:2015 (and current revisions) for chemical composition, mechanical properties, dimensional tolerances, and testing requirements
- Material Certificates: EN 10204 Type 3.1 mill certificates standard; Type 3.2 (third-party inspected) available upon request
- Weld Seam NDT Certification: 100% RT or UT inspection reports provided with each shipment, traceable to EN 10217-7 Class A/B acceptance criteria
- Hydrostatic Test Records: Individual tube pressure test data documented and archived
- ISO 9001: Quality management system certified, ensuring consistent production quality and process control
- CE Marking: Available for pressure equipment applications under the European Pressure Equipment Directive (PED 2014/68/EU)
- Traceability: Full heat number traceability from raw material to finished coil, enabling complete supply chain accountability
Key Selling Points
- European Standard Compliance: Manufactured to EN 10217-7, providing seamless integration into European and international supply chains with recognized quality assurance
- 100% Weld Seam NDT: Comprehensive non-destructive testing ensures zero tolerance for weld defects, delivering unmatched reliability for pressure applications
- Post-Weld Heat Treatment: Solution annealing eliminates residual stresses and ensures full austenitic microstructure, maximizing corrosion resistance and mechanical performance
- Coil Delivery Advantage: Continuous coil form eliminates butt welds in downstream fabrication, reducing material waste by up to 30% and improving production efficiency
- Wide Grade Availability: Multiple austenitic grades available from standard stock, enabling rapid project fulfillment
- Full Traceability & Documentation: Complete quality documentation package including EN 10204 certificates, NDT reports, and hydrostatic test records for every shipment
- Customization: Non-standard dimensions, surface finishes, and packaging configurations available to meet specific project requirements
Note: All specifications are subject to the latest revision of EN 10217-7 and applicable European harmonized standards. For project-specific requirements, contact Wenzhou Jixing Metal Materials Co., Ltd. for technical consultation and customized solutions.