EN 10216-2 Seamless Steel Tubes for Pressure Purposes
Overview
EN 10216-2 is the European standard for seamless steel tubes for pressure purposes - Part 2: Non-alloy and alloy steel tubes with specified elevated temperature properties. It is the modern successor to DIN 17175 and covers seamless tubes for high-temperature service in boilers, heat exchangers, superheaters, and similar pressure equipment.
Steel Grades & Temperature Classes
EN 10216-2 grades are designated by strength level and alloy type, with guaranteed properties at elevated temperatures:
| Grade Designation | Alloy Type | Max Service Temp | Comparable Standards |
|---|---|---|---|
| P195GH | Carbon steel | 300°C | ASTM A53 Gr. A |
| P235GH | Carbon steel | 350°C | ASTM A106 Gr. B, DIN 17175 St 35.8 |
| P265GH | Carbon steel | 350°C | ASTM A106 Gr. C |
| P295GH | Carbon steel | 350°C | - |
| 16Mo3 | 0.3% Mo steel | 500°C | ASTM A335 P1, DIN 17175 15Mo3 |
| 8MoB5-4 | 0.5% Mo-B steel | 500°C | - |
| 13CrMo4-5 | 1% Cr-0.5% Mo | 550°C | ASTM A335 P12, DIN 17175 13CrMo4-5 |
| 10CrMo5-5 | 1.25% Cr-0.5% Mo | 550°C | - |
| 10CrMo9-10 | 2.25% Cr-1% Mo | 580°C | ASTM A335 P22, DIN 17175 10CrMo9-10 |
| 7CrWVMoNb9-6 | 9% Cr-1% Mo-V-Nb | 600°C | ASTM A335 P91 |
| 12CrMo19-5 | 5% Cr-0.5% Mo | 600°C | ASTM A335 P5, DIN 17175 12CrMo19-5 |
| X11CrMo5+NT | 5% Cr-0.5% Mo | 600°C | - |
| X11CrMo9-1+NT | 9% Cr-1% Mo | 600°C | ASTM A335 P9 |
Nomenclature:
P = Pressure purpose
Number = Minimum yield strength in MPa at room temperature
GH = Guaranteed high-temperature properties
Alloy grades: Number indicates approximate % of key alloying elements
Mechanical Properties (Room Temperature)
| Grade | Yield (ReH) Min, MPa | Tensile (Rm), MPa | Elongation (A) Min, % | Impact Test |
|---|---|---|---|---|
| P235GH | 235 | 360-510 | 25 | Optional |
| P265GH | 265 | 410-570 | 22 | Optional |
| 16Mo3 | 270 | 440-590 | 22 | Required |
| 13CrMo4-5 | 280 | 440-590 | 22 | Required |
| 10CrMo9-10 | 280 | 440-590 | 22 | Required |
| 7CrWVMoNb9-6 | 420 | 590-790 | 18 | Required |
| 12CrMo19-5 | 280 | 440-590 | 22 | Required |
Note: "Required" impact testing means Charpy V-notch tests are mandatory.
Chemical Composition (Maximum %, Key Grades)
| Grade | C | Si | Mn | P | S | Cr | Mo | Other |
|---|---|---|---|---|---|---|---|---|
| P235GH | 0.16 | 0.35 | 1.20 | 0.025 | 0.020 | - | - | Altot ≥0.020 |
| P265GH | 0.20 | 0.40 | 1.40 | 0.025 | 0.020 | - | - | Altot ≥0.020 |
| 16Mo3 | 0.14 | 0.35 | 0.80 | 0.025 | 0.020 | - | 0.25-0.35 | Altot ≥0.020 |
| 13CrMo4-5 | 0.15 | 0.35 | 0.80 | 0.025 | 0.020 | 0.70-1.15 | 0.45-0.65 | Altot ≥0.020 |
| 10CrMo9-10 | 0.15 | 0.50 | 0.80 | 0.025 | 0.020 | 2.00-2.50 | 0.90-1.20 | Altot ≥0.020 |
| 7CrWVMoNb9-6 | 0.08-0.12 | 0.20-0.50 | 0.30-0.60 | 0.020 | 0.010 | 8.00-9.50 | 0.85-1.05 | V:0.18-0.25, Nb:0.06-0.10 |
| 12CrMo19-5 | 0.15 | 0.50 | 0.80 | 0.025 | 0.020 | 4.00-6.00 | 0.45-0.65 | Altot ≥0.020 |
Key Features:
Fine grain steel: Aluminum killed for grain refinement (Altot ≥ 0.020%)
Low sulfur: ≤0.020% for better weldability and HIC resistance
Phosphorus control: ≤0.025% for improved toughness
All grades: Fully killed, fine grain practice
Manufacturing Process
Seamless Tube Production:
Steel Making: Basic oxygen or electric arc furnace with secondary refining
Continuous Casting: Fine grain practice with controlled cooling
Hot Working: Mannesmann process (rotary piercing) or extrusion
Heat Treatment: Mandatory - varies by grade:
P195-P295GH: Normalized or normalized & tempered
Alloy grades: Normalized & tempered
Advanced alloys (P91 type): Austenitized, quenched & tempered
Finishing: Sizing, straightening, cutting
Testing: Full compliance with standard requirements
Size Range:
Outside Diameter: 10.2 mm to 711 mm (≈ ⅜" to 28")
Wall Thickness: 1.0 mm to 80.0 mm
Length: Typically 6-12m; up to 18m available
Heat Treatment Requirements
| Grade Category | Mandatory Heat Treatment | Typical Conditions |
|---|---|---|
| Carbon Steels (P195-P295GH) | Normalized or Normalized & Tempered | Normalize: 880-950°C, Air cool |
| Mo & Cr-Mo Alloys (16Mo3-13CrMo4-5) | Normalized & Tempered | Normalize: 900-980°C, Temper: 680-750°C |
| Higher Alloys (10CrMo9-10, etc.) | Normalized & Tempered | Normalize: 920-1000°C, Temper: 680-780°C |
| Advanced 9% Cr (P91 type) | Austenitized, Quenched & Tempered | Austenitize: 1040-1080°C, Quench, Temper: 730-780°C |
Symbols:
+N = Normalized
+NT = Normalized & Tempered
+QT = Quenched & Tempered
+A = Annealed
Testing & Inspection Requirements
| Test | EN Standard Reference | Key Requirements |
|---|---|---|
| Hydrostatic Test | EN 10216-2 Clause 8 | Pressure = 20×S×tDD20×S×t (bar) S = 0.8 × ReH at test temperature Duration ≥ 10 seconds |
| Tensile Test | EN ISO 6892-1 | Room temperature + elevated temperature for some grades Transverse specimens for D ≥ 40 mm |
| Impact Test | EN ISO 148-1 | Mandatory for alloy grades Typically 40J at 20°C or specified temperature |
| Flattening Test | EN ISO 8492 | For D ≤ 50 mm and t/D ≤ 0.1 |
| Bend Test | EN ISO 8491 | Alternative to flattening test |
| Hardness Test | EN ISO 6506-1 | Mandatory for alloy grades Often Brinell or Vickers |
| Nondestructive Test | EN 10246 series | Optional, by agreement (UT, ET, RT) |
| Creep Rupture Test | EN ISO 204 | Optional, for high-temperature design |
Special for Grade 7CrWVMoNb9-6 (P91 type):
Hardness testing mandatory
Microstructure examination
Hardness after tempering: 180-250 HB
Dimensional Tolerances
| Parameter | Tolerance per EN 10216-2 |
|---|---|
| Outside Diameter (D) | D ≤ 101.6 mm: ±0.5 mm or ±0.75% (greater) 101.6 < D ≤ 406.4 mm: ±0.75% D > 406.4 mm: ±1.0% |
| Wall Thickness (t) | +15%, -10% of nominal |
| Eccentricity | ≤ 10% of nominal wall thickness |
| Length | Fixed length: +10 mm, 0 mm |
| Straightness | ≤ 0.15% of total length |
| Weight | ±10% of theoretical weight per single tube |
Applications
Primary Industries:
Power Generation: Boiler tubes, superheaters, reheaters, main steam lines
Petrochemical: Heater tubes, reformer piping, high-temperature process lines
Refining: Catalytic cracker, hydrocracker, visbreaker units
Chemical Industry: High-temperature reactors, heat exchangers
Industrial Boilers: High-pressure steam systems
Typical Service Conditions:
Temperature: 300°C to 600°C (depending on grade)
Pressure: High pressure (100-200 bar typical)
Media: Steam, hot gases, thermal oils, process fluids
Environment: High-temperature industrial applications
Comparison with Other Standards
| Parameter | EN 10216-2 P235GH | ASTM A106 Gr. B | DIN 17175 St 35.8 |
|---|---|---|---|
| Yield Min | 235 MPa | 240 MPa | 235 MPa |
| Tensile Range | 360-510 MPa | ≥415 MPa | 360-480 MPa |
| Carbon Max | 0.16% | 0.30% | 0.17% |
| Sulfur Max | 0.020% | 0.035% | 0.035% |
| Temperature Rating | Guaranteed to 350°C | Up to 400°C | Up to 350°C |
| Grain Refinement | Al-killed (mandatory) | Optional | Al-killed |
Advantages of EN 10216-2:
Guaranteed elevated temperature properties
Stricter chemical controls (lower S, P)
Mandatory fine grain practice
Comprehensive testing requirements
PED compliance for CE marking
Material Certification & Traceability
Required Documentation:
EN 10204 3.2 Certificate: Specific inspection certificate (standard)
Full Traceability: To melt/heat number
Chemical Analysis: Full spectrochemical report
Mechanical Tests: Room and elevated temperature if required
Heat Treatment Records: Times, temperatures, cooling rates
NDE Reports: If ultrasonic or other NDE performed
Mandatory Marking:
Manufacturer's name/trademark
EN 10216-2 designation
Grade (e.g., 13CrMo4-5)
Size (D × t)
Heat number
CE marking (for PED applications)
Heat treatment symbol (e.g., +NT)
Inspection mark
Fabrication & Welding
Welding Guidelines:
Preheat: Required for alloy grades (typically 150-300°C)
Post-Weld Heat Treatment: Mandatory for alloy grades
Filler Metals: Must match or overmatch base metal
Heat Input Control: Critical for alloy grades
Procedure Qualification: Per EN ISO 15614-1
Special Considerations for Grade 7CrWVMoNb9-6 (P91):
Strict preheat: 200-250°C
Interpass temperature: 300°C max
PWHT: 730-780°C for minimum 1 hour
Filler metal: Typically 9Cr-1Mo-V matching
Weld procedure testing: Including creep testing for critical applications
Forming & Bending:
Hot Bending: Preferred for alloy grades
Minimum Bend Radius: Typically 3× OD for cold bending
Springback: Account for in tooling design
Heat Treatment After Bending: Often required for alloy grades
Ordering Information
Essential Data:
Standard: EN 10216-2
Grade: e.g., 13CrMo4-5
Heat treatment condition: +N, +NT, etc.
Dimensions: D (mm) × t (mm) × L (mm or m)
Quantity: Number of pieces or total meters
Certification: EN 10204 3.1 or 3.2
Additional tests: NDT, hardness, impact at specific temperature
End preparation: Plain, bevelled, special
Sample Order:
text
Seamless tubes to EN 10216-2 Grade: 13CrMo4-5 Heat treatment: Normalized & Tempered (+NT) Dimensions: 88.9 × 7.0 × 8000 mm Quantity: 150 pieces Ends: Bevelled 37.5° ± 2.5°, 1.6mm land Certification: EN 10204 3.2 with full traceability Additional: Hardness test report, Charpy impact at 20°C NDT: Full-length ultrasonic testing Marking: Per EN 10216-2 with heat number and CE mark
Industry Usage & Market Position
European Market:
Standard Choice: For high-temperature pressure equipment in EU
PED Compliance: Essential for CE marking
Quality Perception: Premium quality with guaranteed properties
Major Users: Power utilities, oil & gas companies, chemical industry
Global Projects:
Widely specified in European-engineered facilities worldwide
Recognized by international EPC contractors
Often used alongside ASTM standards in multinational projects
Price Position:
Carbon grades: Comparable to ASTM A106
Alloy grades: 20-50% premium over carbon steels
Advanced alloys (P91): Significant premium for performance
Quality Assurance
Key Quality Parameters:
Grain Size: Fine grain structure (ASTM 5 or finer)
Microstructure: Appropriate for service temperature
Hardness: Within specified ranges (critical for alloy grades)
Surface Quality: Free of defects, decarburization controlled
Dimensional Consistency: Uniform wall thickness
Common Inspection Methods:
Ultrasonic Testing: For internal defects and wall measurement
Eddy Current: For surface defects
Magnetic Particle: For surface-breaking defects
Positive Material Identification: For grade verification
Metallographic Examination: For microstructure verification
Equivalent Standards Cross-Reference
| EN 10216-2 Grade | ASTM Equivalent | ISO Equivalent | JIS Equivalent |
|---|---|---|---|
| P235GH | A106 Gr. B | ISO 9329-2 P235 | JIS G3455 STPA 12 |
| 16Mo3 | A335 P1 | - | JIS G3455 STPA 20 |
| 13CrMo4-5 | A335 P12 | ISO 9329-2 13CrMo4-5 | JIS G3455 STPA 23 |
| 10CrMo9-10 | A335 P22 | ISO 9329-2 10CrMo9-10 | JIS G3455 STPA 25 |
| 7CrWVMoNb9-6 | A335 P91 | - | - |
| 12CrMo19-5 | A335 P5 | ISO 9329-2 12CrMo19-5 | JIS G3455 STPA 26 |
Technical Summary
EN 10216-2 is the modern European standard for high-temperature seamless pressure tubes, combining rigorous material controls, mandatory heat treatment, and comprehensive testing to ensure reliable performance in demanding elevated temperature service.
Key Strengths:
Guaranteed Elevated Temperature Properties: Each grade has specified maximum service temperatures with guaranteed mechanical properties
Superior Material Controls: Fine grain practice, low sulfur/phosphorus, controlled alloying
Comprehensive Testing: Mandatory impact testing for alloy grades, hardness controls
PED Compliance: Essential for CE marking of pressure equipment in Europe
Traceability & Documentation: Full material history and test records
Selection Guidelines:
For steam service to 350°C: P235GH or P265GH
For service to 500°C: 16Mo3 or 8MoB5-4
For service to 550°C: 13CrMo4-5 or 10CrMo5-5
For service to 580°C: 10CrMo9-10
For service to 600°C: 7CrWVMoNb9-6 (P91 type) or 12CrMo19-5
When to Specify EN 10216-2:
European Projects: Where EU standards and PED compliance are required
High-Temperature Applications: Above 300°C where guaranteed properties are needed
Critical Services: Power generation, refinery heater tubes, high-pressure steam
Projects with European Engineering: Where material traceability and documentation are critical
When Lifecycle Cost Matters: Superior high-temperature performance reduces maintenance
The standard represents the state-of-the-art in European high-temperature piping materials, with proven performance in some of the world's most demanding industrial applications.
*Note: For applications above 600°C or requiring special alloys, consider EN 10216-5 (seamless tubes of stainless steels) or other specialized standards.*
