EN 10217 Welded Steel Tubes for Pressure Purposes
Overview
EN 10217 is the European standard series specifying welded steel tubes for pressure purposes. It covers various manufacturing processes (including ERW), steel grades, and test requirements for tubes intended for the conveyance of water, steam, gas, and other pressurized fluids.
Key Structure: The standard is divided into 7 parts, each covering different steel types and manufacturing nuances.
Part Structure & Scope
| Part | Title | Key Steel Types / Processes |
|---|---|---|
| EN 10217-1 | Non-alloy steel tubes with specified room temperature properties | P195, P235, P265. ERW & other processes. |
| EN 10217-2 | Electric welded non-alloy and alloy steel tubes with specified elevated temperature properties | P195TR1/2, P235TR1/2, P265TR1/2. ERW is primary process. |
| EN 10217-3 | Alloy fine grain steel tubes | P460NH, P275NH, etc. Welded & normalized. |
| EN 10217-4 | Austenitic stainless steel tubes | Various 304, 316 grades. Welded & solution annealed. |
| EN 10217-5 | Submerged arc welded non-alloy and alloy steel tubes with specified elevated temperature properties | Thicker/larger diameter SAW tubes. |
| EN 10217-6 | Submerged arc welded non-alloy steel tubes with specified low temperature properties | For low temperature service. |
| EN 10217-7 | Stainless steel tubes | Duplex, etc. |
Focus for ERW: EN 10217-1 and EN 10217-2 are the most relevant parts for standard Electric Resistance Welded (ERW) carbon steel pressure tubes.
Steel Grades & Designations (Examples from Part 1 & 2)
| Grade Designation | Minimum Yield Strength (ReH), MPa | Typical Application / Note |
|---|---|---|
| P195 | 195 MPa | General purpose, low pressure. |
| P235 | 235 MPa | Common for water, steam, gas. |
| P265 | 265 MPa | Higher pressure applications. |
| P195TR1, P235TR1, P265TR1 | Same as above | For use up to 300°C. |
| P195TR2, P235TR2, P265TR2 | Same as above | For use up to 450°C. |
The "TR" suffix indicates tubes suitable for elevated temperature service, with guaranteed tensile properties at that temperature.
Mechanical Properties (EN 10217-1 Example)
| Property | P195 | P235 | P265 |
|---|---|---|---|
| Yield Strength (ReH) min, MPa | 195 | 235 | 265 |
| Tensile Strength (Rm), MPa | 320 - 480 | 360 - 510 | 410 - 570 |
| Min. Elongation (A), % | 25 | 23 | 22 |
Tensile strength is a defined range, not just a minimum.
Chemical Composition (Maximum %, EN 10217-1)
| Element | P195 | P235 | P265 |
|---|---|---|---|
| Carbon (C) | 0.13 | 0.16 | 0.20 |
| Manganese (Mn) | 0.70 | 0.80 | 1.20 |
| Phosphorus (P) | 0.025 | 0.025 | 0.025 |
| Sulfur (S) | 0.020 | 0.020 | 0.020 |
Note: Stricter S/P limits than many ASTM standards.
Manufacturing & ERW Process
The standard specifies requirements for tubes made from strip/plate by longitudinal welding. For ERW:
Material: Continuously cast, fine-grain killed steel.
Forming: Cold forming from strip/coil.
Welding: High-Frequency (HF) Induction or Contact Welding.
Weld Treatment: The weld seam may be heat-treated (normalized) to improve properties, especially for grades intended for elevated temperature service (TR grades).
Testing: Mandatory non-destructive testing of the weld seam.
Testing & Inspection Requirements
| Test | Standard Reference | Key Requirement for ERW |
|---|---|---|
| Hydrostatic Test | EN ISO 10893-4 | Test pressure calculated per formula (min 50 bar). Duration ≥ 5 sec. Alternative NDE allowed. |
| Non-Destructive Test of Weld | EN ISO 10893-5 (Eddy Current) or -10 (Ultrasonic) | 100% of weld length for pressure tubes. |
| Tensile Test | EN ISO 6892-1 | On a sample from finished tube, transverse to weld. |
| Flattening Test | EN ISO 8492 | On a ring sample across the weld. |
| Hardness Test | EN ISO 6506-1 | May be specified, especially for TR grades. |
| Visual & Dimensional | EN 10246 series | Surface defects, OD, wall thickness, straightness. |
Typical Dimensions & Tolerances
| Parameter | Typical Range | Common Tolerances (per EN ISO 1127) |
|---|---|---|
| Outside Diameter (D) | 10.2 mm to 711 mm (≈ ½" to 28") | For D ≤ 101.6mm: ±0.5mm or ±0.75% For D > 101.6mm: ±1.0% |
| Wall Thickness (s) | 1.0 mm to 25.0 mm | Typically: +15%, -10% of nominal |
| Length | Random or specified lengths | Up to 24m possible; cut length tolerance: +10 mm / 0 mm |
Application Areas
Boiler and Heat Exchanger Tubes (especially TR grades)
Process Piping in chemical and petrochemical plants
Steam and Condensate Lines
Hydraulic and Pneumatic Systems
Water Distribution Networks (potable and industrial)
Structural Applications under pressure (e.g., cylinders)
Comparison with ASTM Standards
| Aspect | EN 10217 (e.g., Part 1) | Comparable ASTM Standard |
|---|---|---|
| Philosophy | Part of integrated EN/ISO system. | Standalone product spec. |
| Grade Designation | Based on Minimum Yield (Pxxx). | Based on Minimum Yield (Xxx) or Grade Letter. |
| Temp. Rating | Explicit "TR" grades defined. | Often implicit or via supplementary requirements. |
| Sulfur/Phosphorus | Typically lower max limits (e.g., P≤0.025%, S≤0.020%). | Often higher (e.g., P≤0.035%, S≤0.035% in A53). |
| Testing Emphasis | Mandatory 100% weld NDE (EC or UT). | Hydrostatic test often primary; NDE may be alternative. |
Material Certification & Marking
Certification: Tubes are typically supplied with an Inspection Certificate 3.1.B per EN 10204, providing specific test results for the batch.
Mandatory Marking includes:
Manufacturer's name/trademark
Standard number (EN 10217-1)
Steel grade (e.g., P235)
Size (OD x wall thickness)
Heat number
Optional: "TR1" or "TR2" if applicable.
Summary
EN 10217 is the comprehensive European framework for quality welded pressure tubes. For ERW pipe, Part 1 (room temperature) and Part 2 (elevated temperature) are key. Its strengths are integrated material/welding standards, strict impurity controls, and mandatory weld seam NDE.
It is widely accepted in European and international projects governed by pressure equipment directives (PED). When sourcing, specifying the correct Part, Grade (e.g., P235TR2), and required testing certificate is crucial for compliance.
