EN 10217-7 Stainless Steel Welded Pressure Tube – Coil Form
Product Overview
The EN 10217-7 Stainless Steel Welded Pressure Tube, supplied in coil form by Wenzhou Jixing Metal Materials Co., Ltd., represents a premium-grade austenitic stainless steel seamless-equivalent tube engineered for pressure-containing applications under the European standard EN 10217-7. This product is specifically designed for use in pipelines, heat exchangers, chemical processing, and other high-pressure systems where corrosion resistance, mechanical integrity, and long-term reliability are paramount.
As a coil tube product, it offers superior storage efficiency, ease of handling, and cost-effective downstream forming operations compared to straight-length equivalents, while maintaining the full performance envelope mandated by the EN 10217-7 specification.
Material & Properties
The tubes are manufactured from austenitic stainless steel grades compliant with EN 10088-1, most commonly including:
- X2CrNiMo17-12-2 (1.4435) – equivalent to UNS S31625, offering enhanced pitting and crevice corrosion resistance
- X2CrNi18-12 (1.4307) – equivalent to UNS S30408, providing excellent general corrosion resistance and formability
- X2CrNiN18-10 (1.4362) – nitrogen-stabilized variant for improved yield strength without sacrificing ductility
- X2CrNiMo17-12-3 (1.4404) – equivalent to UNS S31603, high-performance duplex-compatible grade for aggressive environments
Key metallurgical characteristics include:
- Corrosion Resistance: Superior resistance to atmospheric, chemical, and chloride-induced corrosion
- Mechanical Properties: Minimum yield strength of 205 MPa (depending on grade and wall thickness); ultimate tensile strength ranging from 480–700 MPa
- Temperature Capability: Continuous service from cryogenic temperatures (−196°C) up to +600°C
- Non-magnetic: Austenitic microstructure ensures non-magnetic properties in annealed condition
Specifications
| Parameter | Specification / Value |
|---|---|
| Governing Standard | EN 10217-7:2006 – Tubes for pressure purposes – Technical delivery conditions – Part 7: Stainless steel tubes, welded |
| Product Form | Coil Tube (盘管) – continuous coil configuration |
| Manufacturing Method | Welded (ERW / GMAW / TIG) – longitudinal or spiral weld |
| Outer Diameter (OD) | 10 mm – 426 mm (per EN 10217-7 dimensional ranges) |
| Wall Thickness (WT) | 0.5 mm – 12 mm (subject to grade and OD combination) |
| Coil Length | Typically 100 m – 500 m per coil; custom lengths available |
| Heat Treatment Condition | Solution Annealed (solid solution heat treatment); optionally Pickled & Passivated (P&P) |
| Weld Seam NDT Grade | 100% Radiographic Testing (RT) or Ultrasonic Testing (UT) per EN 10229; acceptance per EN ISO 5817 Grade B or better |
| Surface Finish | Mill finish (pickled & passivated); optional BA (Bright Annealed) or polished finish upon request |
| Hydrostatic Test | 100% hydrostatic pressure testing per EN 10204 3.1 certification |
| Dimensional Tolerances | Per EN 10217-7 Table 5 (OD tolerance ±0.5 mm to ±1.0 mm; wall thickness tolerance ±10% or ±0.1 mm, whichever is greater) |
| Certification | EN 10204 Type 3.1 (and optionally Type 3.2 for third-party inspection) |
Manufacturing Process
The production of EN 10217-7 stainless steel welded pressure coil tubes follows a rigorously controlled multi-stage process:
- Steel Coil Preparation: Cold-rolled stainless steel strip of certified mill quality is received and inspected for surface integrity, dimensional accuracy, and chemical composition compliance.
- Forming & Welding: The strip is cold-formed into a circular cross-section and welded using either Electric Resistance Welding (ERW) for thinner wall sections or Gas Metal Arc Welding (GMAW) / Tungsten Inert Gas (TIG) welding for heavier wall thicknesses. The welding process is precisely calibrated to ensure full penetration and minimal heat-affected zone (HAZ) distortion.
- Weld Seam Treatment: The weld seam undergoes either internal/external grinding and polishing to achieve a smooth surface profile, or is left in a controlled as-welded condition depending on application requirements.
- Solution Annealing (Heat Treatment): Tubes are subjected to a solid solution heat treatment at 1050°C–1150°C followed by rapid water quenching. This process dissolves carbides, restores full austenitic microstructure, and ensures optimal corrosion resistance and mechanical properties.
- Pickling & Passivation: Tubes are acid-pickled to remove oxide scale and then passivated to form a protective chromium oxide film on the surface.
- Non-Destructive Testing (NDT): 100% of weld seams are subjected to radiographic testing (RT) or ultrasonic testing (UT) in accordance with EN 10229. Acceptance criteria follow EN ISO 5817 Grade B minimum, with stricter grades available upon request.
- Hydrostatic Pressure Testing: Each tube coil is subjected to 100% hydrostatic testing at a pressure calculated per EN 10217-7 formulas, with a minimum test pressure of 1.5× the maximum allowable working pressure (MAWP).
- Dimensional Inspection: Outer diameter, wall thickness, ovality, and coil length are verified using automated gauging systems with documented traceability.
- Coiling & Packaging: The finished tube is coiled onto a steel core with appropriate inner diameter for customer-specific handling requirements, then wrapped in protective material and secured for shipment.
Applications
EN 10217-7 stainless steel welded pressure coil tubes are deployed across a broad spectrum of demanding industrial sectors:
- Chemical & Petrochemical Industry: Process piping for corrosive media transfer, reactor feed lines, and catalyst delivery systems
- Oil & Gas: Subsea pipeline systems, offshore platform piping, and high-pressure gas handling
- Power Generation: Boiler feedwater systems, steam lines, and condensate return in thermal and nuclear power plants
- Food & Beverage Processing: Hygienic piping for dairy, pharmaceutical, and beverage production requiring high sanitary standards
- Heat Exchanger Manufacturing: Tubular heat exchangers, condensers, and evaporators where coil form enables efficient tube bending and installation
- Marine & Offshore: Ballast systems, seawater piping, and deck equipment in marine environments
- Structural & Mechanical Engineering: High-pressure hydraulic systems, pneumatic lines, and pressure vessels
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring full compliance with international standards:
- ISO 9001:2015 – Quality Management System certification
- EN 10204 Type 3.1 – Manufacturer's test report with witnessed testing by authorized personnel
- EN 10204 Type 3.2 – Third-party inspected certification available upon request (NACE / ASME stamping compatible)
- CE Marking – Conformity with European Pressure Equipment Directive (PED 2014/68/EU)
- Mill Test Certificates (MTC) – Full chemical analysis, mechanical test results, and NDT reports provided with every shipment
Unique Selling Points
- Coil Configuration Advantage: Delivered in continuous coil form, enabling reduced handling costs, minimal waste during downstream processing, and optimized inventory management for high-volume consumers
- Full EN 10217-7 Compliance: Every coil undergoes 100% hydrostatic testing and weld seam NDT with documented traceability from raw material to finished product
- Flexible Grade Selection: Multiple austenitic stainless steel grades available to match specific corrosion, temperature, and mechanical requirements
- Customized Specifications: Outer diameter, wall thickness, coil length, surface finish, and heat treatment condition are all available in customer-specific configurations
- Traceable Quality: Full material traceability from steel mill through to final coil, with digital documentation available for regulatory audit purposes
Note: All products supplied under the EN 10217-7 specification are manufactured and tested in strict accordance with the latest revision of the standard. For applications subject to specific regulatory regimes (e.g., PED, ASME, NORSOK), additional certifications and markings can be provided upon request during the ordering process.