EN10217
Overview of the EN10217 Standard System
EN10217 is a series of standards for welded steel pipes used in pressure equipment, developed by the European Committee for Standardization (CEN). The latest version is the 2019 edition (including Parts 1–7), covering three major categories—non-alloy steel, alloy steel, and stainless steel—with a total of 32 steel grades. It is applicable to high-temperature/low-temperature pressure scenarios such as petrochemicals, power boilers, and shipbuilding. Its core value lies in:
Full operational condition coverage: from -196°C low temperature (Part 6) to 600°C high temperature (Part 2)
Process adaptability: management of welding methods such as high-frequency welding (HFW) and submerged arc welding (SAW)
Certification compatibility: compliant with the EU Pressure Equipment Directive (2014/68/EU) and the Construction Products Regulation (CPR), enabling global trade compatibility.
I. Core Content Analysis: Grading System and Tolerance Requirements
1. Grading System and Applicable Materials
| Standard | Volume Core Material Type | Typical Steel Grade | Key Performance Characteristics |
| EN10217-1 | Non-alloy Steel (Room Temperature) | P235GH, P265GH | Yield Strength 235–265 MPa, Carbon Equivalent ≤0.48% |
| EN10217-2 | Non-alloy/Alloy Steel (High Temperature) | St37.8 (+N | High-temperature yield strength ≥105 MPa at 500°C |
| EN10217-3 | Fine-Grained Alloy Steel | 13CrMo4-5 | Grain size ≥Grade 6 (ASTM) |
| EN10217-4 | Austenitic stainless steel | X2CrNi18-9 (304L) | Solution treatment + intergranular corrosion test |
| EN10217-6 | Austenitic stainless steel | X2CrNi18-9 (304L) | Solution treatment + intergranular corrosion test |
| EN10217-7 | Stainless steel submerged arc welded pipe | X2CrNiMoN22-5-3 (31803) | Duplex steel resistant to chloride ion corrosion |
2. Geometric tolerance requirements (stricter than most national standards)
Outer diameter deviation: ±0.75% D (compared to GB/T 9711: ±1% D)
Wall thickness deviation:
Average wall thickness: ±10% t
Minimum wall thickness: +22% t / -0% (standard grade), +20% t / -0% (higher grade)
Length deviation: ±50 mm (heat exchanger tubes ±4 mm/6 m)
Weld bead height: ≤0.25 mm when outer diameter ≤38 mm, ≤0.1t + 0.5 mm when >38 mm Wall thickness deviation:
3. Mandatory test items
| Test type | Applicable standard | Frequency requirement | Key indicators |
| Chemical composition analysis | EN ISO 14284 | Per furnace charge | P/S content, Cr/Ni equivalent |
| Room Temperature Tensile Test | EN ISO 6892-1 | 2 samples per batch of 200 bars | Rp0.2, Rm, A% (e.g., P265GH: Rm ≥ 410 MPa) |
| High-Temperature Yield Strength | EN ISO 6892-2 | Grade 2 Specific | St37.8 at 500°C: Rp0.2 ≥ 105 MPa |
| Impact toughness | EN ISO 148-1 | Low-temperature pipes (Part 6) | -50°C KV ≥ 27 J |
| Hydrostatic test | EN ISO 10893 | Individual pipes | Pressure = 2 × design stress × wall thickness / outer diameter |
| Non-destructive testing | EN ISO 11496 | 100% UT + RT sampling | PSL2 grade requires full weld RT |
| Special Tests | |||
| Intergranular Corrosion | ASTM A262 Practice E | Austenitic Stainless Steel | Boiling Nitric Acid Method, Weight Loss Rate ≤2.0 g/m²h |
| High-temperature creep | EN 10291 | Alloy steel (Part 2/5) | 1% creep limit (e.g., 11CrMo9-10 at 550°C ≥ 80 MPa) |
Note: Part 7 stainless steel tubes require 100% spectroscopic analysis (PMI) to verify composition 7
II. Detailed Explanation of Material Properties: Chemical Composition and Mechanical Properties
1. Chemical Composition Control (Typical Grade Examples)
| Steel Grade (EN10217) | C≤ | Mn | P≤ | S≤ | Cr | Ni | Mo | Special Requirements |
| P235GH (Part 1) | 0.16% | 0.60-1.20% | 0.025% | 0.015% | – | – | – | CEV≤0.48% |
| X2CrNiMo17-12-2 (Part 4) | 0.030% | 2.00% | 0.045% | 0.015% | 16.5-18.5% | 10.0-13.0% | 2.0-2.5% | PREN≥25 |
| S355J2H (Part 6) | 0.22% | ≤1.60% | 0.025% | 0.010% | – | – | – | Al≥0.020% Grain refinement |
2. Mechanical Properties Classification Requirements
Room Temperature Properties (Part 1/4/7)
P265GH: Rp0.2 ≥ 265 MPa, Rm ≥ 410 MPa, A ≥ 24%3
X2CrNiMo17-12-2: Rp0.2 ≥ 220 MPa, Rm ≥ 520 MPa, A ≥ 35%
High-Temperature Properties (Part 2)
St37.8 at 400°C: Rp0.2 ≥ 110 MPa, thermal conductivity 45 W/(m·K)9
Low-Temperature Toughness (Part 6)
S355J2H at -50°C: Impact energy ≥40 J (longitudinal), yield-to-tensile strength ratio ≤0.923
3. Process Performance and Corrosion Resistance
Flattening test: Weld located at a 90° position, flattened to H=0.6D with no cracks
Intergranular corrosion: After sensitization at 650°C, 304L steel is tested according to ASTM A262 Method E, with a corrosion rate ≤1.2 μm/h
Duplex steel pitting potential: S31803 has a potential ≥1000 mV (SCE) in a 3.5% NaCl solution
III. Engineering Applications and Selection Guidelines
1. Typical Application Scenarios
Energy and Power: Boiler superheater tubes (Part 2’s 11CrMo9-10, resistant to 540°C steam) 3
Petrochemical Refining: Hydrogenation reactor feed pipes (Part 5’s X10CrMoVNb9-1, resistant to hydrogen embrittlement)
LNG Cryogenic Storage Tanks: -196°C liquid nitrogen pipes (Part 6’s S355J2H)
Seawater Systems: Ship seawater cooling pipes (Part 7’s S31803 duplex steel, resistant to chloride ion corrosion)
2. Selection Decision Tree
3. Special Process Requirements
Post-welding heat treatment:
Carbon steel welded pipes: Stress-relief annealing at ≥600°C (mandatory for wall thicknesses >20mm)
Stainless steel pipes: Solution treatment (water quenching at 1040–1100°C)
Surface treatment:
Heat exchanger tubes: Internal shot blasting (Sa 2.5 grade) to reduce flow resistance
Offshore engineering pipes: External wall 3PE coating (≥2.5 mm)
4. Comparison of Chinese and foreign materials and alternative solutions
1. Equivalence between Chinese and European steel grades
| EN10217 steel grade | Chinese GB standard | Performance deviation | Feasibility of substitution |
| P235GH | 20G (GB/T 5310) | 10% lower high-temperature strength (at 300°C) | Limited to T≤400°C |
| P265GH | Q345R (GB 713) | Equivalent impact toughness | stricter S/P control Fully substitutable |
| X2CrNi18-9 | 06Cr19Ni10 (GB/T 20878) | Consistent intergranular corrosion performance | Fully substitutable |
| S355J2H | Q355D (GB/T 1591) | mpact energy at -50°C: GB requirement ≥34 J (European standard ≥40 J) | Additional testing required |
2. Manufacturing tolerance compensation strategy
When substituting national standard materials for EN 10217, the following adjustments are required:
Additional wall thickness allowance: When substituting Q345R for P265GH, wall thickness × 1.08 to compensate for strength reduction of 5
Non-destructive testing upgrade: GB/T 9711 L2-grade pipes require an increase in RT sampling to 20% (aligned with EN PSL2)
Enhanced corrosion protection: In acidic environments, Q345R must add a 316L stainless steel lining (0.8 mm)
Case study: Hydrogenation reactor pipes at a chemical plant in Zhejiang Province originally designed using EN 10217-5 X10CrMoVNb9-1 were later replaced with domestic 12Cr2Mo1VR (GB 5310) through three process optimizations to achieve equivalent substitution:
Rolling process changed from normalizing to quenching + tempering (QT state), increasing Rp0.2 to 350 MPa;
Localized high-frequency tempering of the weld zone (760°C × 2 hours) to eliminate the soft zone in the heat-affected zone (HAZ);
Additional wet H₂S corrosion testing (NACE TM0177) confirmed compliance with SSCC resistance performance requirements.
V. Standard Development Trends
Green Manufacturing Requirements
The 2025 draft version introduces new requirements for carbon footprint tracking (CO₂ emissions from steel production to finished pipe ≤1.8 t/t) and recycled steel content (≥30%) 3
Smart Detection Technology
AI-based automatic defect identification (ADI system) replaces manual film evaluation
Fiber optic sensing pipes: embedded FBG sensors for real-time monitoring of strain/temperature 6
Material Innovation Directions
Additive manufacturing welded pipes: corrosion-resistant composite pipes with laser-clad IN625 alloy linings
High-entropy alloy applications: CoCrFeNiMn-based welded pipes (PREN ≥ 45)
Conclusion: The “European gene” of pressure systems
EN10217 establishes a comprehensive technical framework for pressure-bearing welded pipes through graded adaptation (7 material categories), precision tolerances (outer diameter ±0.75%), and full-condition validation (-196°C to 600°C). Its core advantages include:
Performance traceability: Each steel pipe is accompanied by a digital twin label (including melting/heat treatment/test data)
Failure prevention design: e.g., limiting P ≤ 0.025% to suppress low-temperature brittle fracture, and mandatory intergranular corrosion testing to prevent stress corrosion cracking
Global certification compatibility: PED directive endorsement reduces trade technical barriers
Engineering recommendations: When selecting European and Chinese material substitutes, it is necessary to simultaneously verify thickness effect compensation (national standard strength decreases with thickness), corrosion margin addition (acidic medium +1 mm), and welding material compatibility (e.g., ENiCrMo-3 electrodes compatible with duplex steel) to achieve optimal lifecycle costs.
