EN 10217-1 Welded Steel Tubes for Pressure Purposes - Carbon Steel Boiler Steel Pipe
Introduction
EN 10217-1 is a European harmonized standard that specifies the technical delivery conditions for electric welded and submerged arc welded non-alloy and alloy steel tubes (pipes) with specified elevated temperature properties. It is part of the EN 10217 series (Parts 1-7), which covers various types of pressure tubes.
Tubes conforming to this standard are primarily designed for pressure and high-temperature service, making them suitable for boilers, heat exchangers, and superheaters in power plants and industrial installations. Unlike ASTM standards which often have grade designations based on strength (e.g., A106 B), EN 10217-1 uses steel grade designations (e.g., P235GH, P265GH) that indicate the minimum yield strength and the application type.
Key Characteristics
Material: Non-alloy and alloy quality steels with specified high-temperature properties.
Manufacturing Process: Electric Welding (EW) or Submerged Arc Welding (SAW).
Key Property: Guaranteed mechanical properties at room temperature and at elevated temperatures (typically up to 300-500°C).
Standard: EN 10217-1: Welded steel tubes for pressure purposes - Technical delivery conditions - Part 1: Non-alloy steel tubes with specified room temperature properties.
Note: Despite the "room temperature" in the part title, the standard includes grades (like PxxxGH) with specified elevated temperature properties. It's a classification nuance.
Primary Application: Pressure equipment such as boilers, superheaters, heat exchangers, and associated piping operating at elevated temperatures.
Common Steel Grades & Application
The most common boiler-related grades in EN 10217-1 are the "GH" grades, where:
P: Stands for "Pressure" purpose.
235/265/...: The minimum yield strength (ReH) in MPa at room temperature.
GH: Stands for "Gases Hochdruck" (Gases High Pressure), indicating suitability for elevated temperature service.
| Grade Designation | Minimum Yield Strength (ReH) | Typical Application in Boiler Systems |
|---|---|---|
| P235GH | 235 MPa | Low to medium pressure boiler parts, headers, general pressure piping. |
| P265GH | 265 MPa | Widely used for boiler tubes, superheaters, and pressure vessels. |
| P295GH | 295 MPa | For higher pressure sections of boilers and heat exchangers. |
Chemical Composition (Maximum %, Melt Analysis - Common Grades)
| Element | P235GH | P265GH | P295GH | Notes |
|---|---|---|---|---|
| Carbon (C) | 0.16 | 0.20 | 0.20 | Controlled for weldability and strength. |
| Silicon (Si) | 0.40 | 0.40 | 0.40 | Deoxidizer. |
| Manganese (Mn) | 1.20 | 1.40 | 1.50 | Primary strengthening element. |
| Phosphorus (P) | 0.025 | 0.025 | 0.025 | Impurity, kept very low. |
| Sulfur (S) | 0.015 | 0.015 | 0.015 | Impurity, kept very low. |
| Aluminum (Altot) | 0.020 min | 0.020 min | 0.020 min | For grain refinement (fine grain practice). |
| Nitrogen (N) | 0.012 | 0.012 | 0.012 | Controlled to prevent aging. |
Note: The steel is fully killed and made to fine grain practice. Product analysis allows for tolerances.
Mechanical Properties at Room Temperature
| Property | Symbol | P235GH | P265GH | P295GH | Test Standard |
|---|---|---|---|---|---|
| Yield Strength (min) | ReH | 235 MPa | 265 MPa | 295 MPa | EN ISO 6892-1 |
| Tensile Strength | Rm | 360-510 MPa | 410-530 MPa | 430-560 MPa | EN ISO 6892-1 |
| Elongation (min) | A | 25% (on L0=5.65√So) | 23% | 22% | EN ISO 6892-1 |
| Impact Energy (min) | KV | Optional Requirement | Optional Requirement | Optional Requirement | EN ISO 148-1 |
| If ordered: ≥ 27 J avg at 20°C | If ordered: ≥ 27 J avg at 20°C | If ordered: ≥ 27 J avg at 0°C |
Impact Test Note: For low-temperature applications or specific safety requirements, Charpy V-notch impact testing can be specified in the purchase order at a defined temperature.
Elevated Temperature Properties (Specified Values)
A key feature of EN 10217-1 "GH" grades is the provision of proof strength (Rp0.2) values at elevated temperatures, which are essential for boiler design.
| Grade | Proof Strength at Temperature, Rp0.2 (min, MPa) |
| :--- | :--- | :--- | :--- | :--- |
| | 50°C | 100°C | 150°C | 200°C | 250°C | 300°C |
| P235GH | 195 | 175 | 155 | 135 | 125 | 115 |
| P265GH | 235 | 215 | 195 | 175 | 165 | 155 |
| P295GH | 255 | 235 | 215 | 195 | 185 | 175 |
Note: Values are for reference. The complete standard provides values up to 500°C. Design must use the values from the official standard edition.
Non-Destructive Testing (NDT)
Mandatory NDT is required to ensure weld integrity:
Seam Weld Testing: The entire longitudinal weld seam is subjected to eddy current testing (ECT) or ultrasonic testing (UT).
Optional Higher Class: Tubes can be supplied to Class I (standard testing) or the more stringent Class II, which may require additional or more sensitive testing (e.g., full-body UT, radiography) as agreed upon.
Typical Applications
Water-Tube Boilers: Evaporator tubes, risers, downcomers.
Superheaters and Reheaters: High-temperature steam tubes.
Boiler Headers and Drums: Main pressure collection/distribution points.
Heat Exchangers and Condensers.
General Pressure Piping in power generation and process industries.
Comparison with Key ASTM Standards
| Feature | EN 10217-1 (e.g., P265GH) | ASTM A178 / A192 (Boiler Tubes) | ASTM A671 (Plate Pipe) |
|---|---|---|---|
| Origin | European (CEN) Standard | American (ASTM) Standard | American (ASTM) Standard |
| Typical Form | Welded Tube (EW, SAW) | Seamless or ERW Tube | Welded Plate Pipe (EFW) |
| Key Data Provided | Room & Elevated Temp Yield/Proof Strength | Room Temp Tensile, Hydrostatic Test Pressure | Room Temp Tensile, Optional Impact |
| Common Application | European-designed boilers, Heat exchangers | Boiler tubes, Superheater tubes in US designs | Large-diameter headers, Pressure vessels |
| Grade Designation | Based on Min YS (PxxxGH) | Based on chemistry & tensile (A, C, D) | Based on YS & condition (CC60, CH100, CF66) |
Certification & Marking
Certification: Tubes are supplied with an Inspection Certificate 3.1 according to EN 10204, stating compliance with EN 10217-1.
Marking: Each tube or bundle is clearly marked with:
Manufacturer's name/trademark
Grade (e.g., P265GH)
Standard (EN 10217-1)
Size
Heat number
Optional: Class (I or II) and test pressure.
Important Note: EN 10217-1 is a harmonized standard under the European Pressure Equipment Directive (PED). Compliance with it provides a presumption of conformity with the essential safety requirements of the PED for the materials covered, facilitating the CE marking of pressure equipment. Selection must always be based on the latest official standard edition and the specific design code (e.g., EN 12952 for water-tube boilers).
