Stainless Steel Seamless Pressure Tubes (Coil Tube) — EN 10216-5
Product Overview
The Stainless Steel Seamless Pressure Tubes (Coil Tube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd conform to the European standard EN 10216-5 — "Steel tubes for pressure purposes — Technical delivery conditions — Part 5: Non heat-resistant seamless austenitic stainless steel tubes." These tubes are engineered for demanding pressure-containing applications and are fully aligned with the PED (Pressure Equipment Directive 2014/68/EU), ensuring compliance with European safety regulations for the design, manufacture, and assessment of pressure equipment.
This product line represents the highest tier of European quality standards for seamless austenitic stainless steel tubing, offering superior corrosion resistance, mechanical integrity, and dimensional precision suitable for critical industrial applications across Europe and globally.
Material & Properties
The tubes are fabricated from austenitic stainless steel grades as specified in EN 10216-5, which encompasses a range of non heat-resistant austenitic compositions. The primary material grades include:
- 1.4301 / 1.4401 (equivalent to AISI 304 / 316) — General-purpose austenitic grades offering excellent corrosion resistance and formability.
- 1.4571 (AISI 321) — Stabilized grade with titanium addition for enhanced resistance to intergranular corrosion.
- 1.4539 (AISI 347) — Stabilized grade with niobium addition for high-temperature structural stability.
- 1.4462 (AISI 316L) — Low-carbon variant offering superior weldability and resistance to pitting and crevice corrosion.
- 1.4404 / 1.4522 (AISI 316L / 317L) — Enhanced molybdenum-bearing grades for aggressive chemical environments.
Key material properties include:
- Yield Strength (Rp0.2): Typically ≥ 205 MPa (varies by grade and wall thickness)
- Tensile Strength (Rm): Typically 520–750 MPa
- Elongation (A5): ≥ 35% (minimum)
- Corrosion Resistance: Exceptional resistance to atmospheric, chemical, and marine environments
- Operating Temperature Range: −196°C to +450°C (non heat-resistant classification)
- Microstructure: Fully austenitic, non-magnetic (or slightly magnetic after cold working)
Specifications
| Parameter | Specification |
|---|---|
| Standard | EN 10216-5 |
| Product Form | Seamless Tube in Coil (Coil Tube) |
| Manufacturing Method | Hot-Finished Seamless (HFW) / Cold-Finished Seamless (CFS) |
| Outer Diameter (OD) | 6.0 mm – 219.1 mm (as per EN 10216-5 dimensional series) |
| Wall Thickness | 0.8 mm – 20.0 mm |
| OD Tolerance | ±10% (standard) / ±5% (tight tolerance on request) |
| Wall Thickness Tolerance | −12.5% to +12.5% (standard) |
| Length (Coil) | Continuous coil, typical 50–200 m per coil |
| Surface Finish | Hot-rolled, pickled, and descaled (HOT) / Cold-drawn bright annealed (CDA) |
| End Condition | Plain ends (coil form) / Cut to length with plain or beveled ends |
| Test Categories | TC1 (Basic Examination) / TC2 (Extended Examination) |
| PED Compliance | Compliant with Directive 2014/68/EU — Categories I, II, III, IV |
| Heat Treatment | Solution annealed at 1050–1150°C, followed by rapid cooling (water quench) |
| Coil Weight | Typically 1,000 – 3,000 kg per coil |
Manufacturing Process
The production of EN 10216-5 compliant seamless pressure tubes follows a rigorous multi-stage manufacturing process:
- Billet Preparation: High-purity austenitic stainless steel billets are sourced from certified mills, with full chemical composition verification per EN 10204 3.1/3.2 certification.
- Heating & Piercing: Billets are heated to 1,100–1,200°C and pierced through a mandrel to produce a hollow shell (Hollow Blanked Billet — HBB process, or conventional piercing).
- Hot Rolling / Elongation: The hollow shell is elongated through a series of rolling stands to achieve the target outer diameter and wall thickness dimensions.
- Cold Working (Optional): Tubes requiring tighter dimensional tolerances undergo cold drawing or cold reduction through calibrated dies and mandrels.
- Solution Annealing: Tubes are reheated to 1,050–1,150°C and rapidly quenched in water to dissolve carbide precipitates, restore full austenitic microstructure, and achieve optimal mechanical and corrosion properties.
- Pickling & Descaling: Surface oxide scales are removed through controlled acid pickling (nitric-hydrofluoric acid blend) to achieve a clean, uniform surface finish.
- Coiling: Finished tubes are wound into coils using precision coiling equipment to maintain dimensional stability and prevent surface damage.
- Final Inspection & Testing: Comprehensive non-destructive testing (NDT) and destructive testing are performed per the designated test category.
Testing & Quality Assurance
EN 10216-5 defines two test categories to accommodate different application criticality levels:
| Test Category | Description | Required Tests |
|---|---|---|
| TC1 — Basic Examination | Standard examination for general pressure applications | Hydrostatic test, chemical analysis, dimensional measurement, visual inspection |
| TC2 — Extended Examination | Enhanced examination for critical/high-integrity pressure applications | All TC1 tests plus: mechanical testing (tensile, hardness), ultrasonic testing (UT), positive material identification (PMI), intergranular corrosion test (IGC), impact testing (Charpy V-notch) |
Additional quality measures include:
- Hydrostatic Pressure Test: Each tube is subjected to a hydrostatic test at a pressure of 1.5×(2S×t/D), where S is the allowable stress, t is the wall thickness, and D is the outer diameter.
- Ultrasonic Testing (UT): Full-length ultrasonic examination to detect internal defects such as laminations, cracks, and inclusions.
- Positive Material Identification (PMI): Spectroscopic verification of chemical composition for material traceability.
- Intergranular Corrosion Test (IGC): Per ASTM A240 / EN ISO 3659, confirming resistance to sensitization after welding.
- Mechanical Testing: Tensile tests on samples taken from the production lot to verify yield strength, tensile strength, and elongation values.
Quality Certifications
- EN 10216-5 — Technical delivery conditions for non heat-resistant seamless austenitic stainless steel tubes
- PED 2014/68/EU — Pressure Equipment Directive compliance for all categories (I–IV)
- EN 10204 — Type 3.1 / Type 3.2 test certificates available
- ISO 9001:2015 — Quality Management System certification
- CE Marking — Conformity assessment for European market access
- AD 2000-Merkblatt — German pressure equipment regulations compatibility
- BS EN 10216-5 — British Standard adoption of European specification
Applications
EN 10216-5 stainless steel seamless pressure tubes in coil form are widely utilized across multiple industries requiring reliable pressure containment and corrosion resistance:
- Petrochemical & Oil/Gas: Process piping systems, heat exchangers, reactor internals, and refinery instrumentation lines.
- Power Generation: Steam systems, boiler feedwater lines, nuclear facility cooling circuits, and condensate return systems.
- Pharmaceutical & Biotechnology: Clean-in-place (CIP) piping, sanitary process lines, and sterile fluid transfer systems.
- Food & Beverage: Hygienic processing lines, dairy equipment, and brewing plant piping.
- Marine & Offshore: Seawater cooling systems, ballast piping, and offshore platform pressure systems.
- Chemical Processing: Acid/alkali transfer lines, chemical dosing systems, and evaporator tubes.
- Automotive: Fuel systems, brake lines, and exhaust system components requiring corrosion resistance.
- Compressed Air & Pneumatics: Air compressor discharge lines, pneumatic control systems, and instrument air distribution.
Unique Selling Points
1. Full PED Compliance with TC1/TC2 Flexibility
Wenzhou Jixing Metal Materials provides seamless pressure tubes that meet the complete requirements of the European Pressure Equipment Directive (PED 2014/68/EU), with the option to select either TC1 (basic) or TC2 (extended) examination categories — offering clients the optimal balance between cost-efficiency and quality assurance based on application criticality.
2. Coil Form Advantage
The coil tube format eliminates the need for field welding of short-length segments, reducing installation costs, minimizing leak points, and enabling continuous tube routing for complex process layouts. This is particularly advantageous for heat exchanger tube bundles, long-run process piping, and automated tube-forming applications.
3. Seamless Construction Integrity
The seamless manufacturing process ensures uniform material properties throughout the tube cross-section without weld seams — eliminating the weakest link in welded alternatives and providing superior fatigue resistance and pressure containment reliability.
4. Multi-Grade Availability
Comprehensive range of austenitic grades (304, 316, 316L, 321, 347, 317L, and duplex variants) allows precise material selection tailored to specific corrosion environments, temperature ranges, and mechanical requirements.
5. European Standard Alignment
Direct compliance with EN 10216-5 ensures seamless integration into European and international projects governed by CE marking requirements, reducing qualification time and regulatory barriers for global procurement.
Conclusion
Wenzhou Jixing Metal Materials Co., Ltd delivers EN 10216-5 compliant stainless steel seamless pressure tubes in coil form that represent the gold standard for European pressure equipment applications. With full PED conformity, flexible TC1/TC2 testing categories, and a comprehensive range of austenitic grades, these products provide engineering confidence for the most demanding pressure-containing systems worldwide.