What is the equivalent European grade for SA387 Grade 11 Class 2?
SA387 Grade 11 Class 2 is a normalized and tempered chromium-molybdenum (Cr-Mo) alloy steel plate specifically designed for the construction of welded pressure vessels and high-temperature components in demanding industrial service.
The closest and most widely accepted European equivalent for SA387 Grade 11 Class 2 is 13CrMo4-5 (Material Number 1.7335) as specified in the standard EN 10028-2: Flat products made of steels for pressure purposes.
Key Details of the Equivalency:
| Feature | SA387 Grade 11 Class 2 | European Equivalent: 13CrMo4-5 (1.7335) |
|---|---|---|
| Standard | ASME SA387 / ASTM A387 | EN 10028-2 |
| Main Alloying | 1.25% Chromium, 0.5% Molybdenum | ~1.0-1.5% Chromium, 0.5-0.7% Molybdenum |
| Common Condition | Normalized and Tempered (N&T) | Normalized and Tempered or Normalized (+N or +NT) |
| Key Application | High-temperature pressure vessels | High-temperature pressure vessels & components |
Important Considerations for Direct Equivalency:
1.Heat Treatment Condition is Critical:
SA387 Grade 11 Class 2 is supplied in the Normalized and Tempered condition. To be fully equivalent, the European 13CrMo4-5 plate must also be ordered in the normalized and tempered (+NT) delivery condition. It is commonly supplied this way, but verification on the material certificate is essential.
2.Not a 100% Identical Match:
While the chemical composition and application are extremely close, the specified ranges for elements like Chromium, Molybdenum, and tensile strength are not perfectly identical. For ASME code construction, the SA387 material is always the governing specification. 13CrMo4-5 is used as an equivalent only if it is certified to meet all the requirements of SA387 Grade 11 Class 2.
3.Certification Matters:
For a pressure vessel built to ASME rules, the plate must ultimately be certified as meeting SA387. A mill test certificate (MTC) for 13CrMo4-5 to EN 10204 3.1 or 3.2 must be reviewed by the manufacturer's engineer and the Authorized Inspector to confirm it meets all SA387 requirements.
Other Related European Designations:
EN 10222-2 (Forgings): The equivalent forging specification is 13CrMo4-5.
EN 10216-2 (Pipes): The equivalent seamless pipe specification is 13CrMo4-5.
Practical Recommendation:
When sourcing material for an ASME pressure vessel, the safest path is to specify:
"SA387 Grade 11 Class 2 per ASME Section II, Part A, or equivalent European grade 13CrMo4-5 supplied in normalized and tempered condition and certified to meet all requirements of SA387 Gr.11 Cl.2."
This ensures the supplier understands the required technical parity.
In summary
for engineering and procurement purposes in Europe, 13CrMo4-5 (1.7335) in the normalized and tempered condition is considered the direct functional equivalent of SA387 Grade 11 Class 2 for pressure vessel plate applications.
1. What is SA387 Grade 11 Class 2?
SA387 Grade 11 Class 2 is a normalized and tempered chromium-molybdenum (1¼Cr-½Mo) alloy steel plate designed for high-temperature pressure vessels, offering higher strength than Class 1 while maintaining good weldability and creep resistance in refinery service.
2. What are the mechanical properties of SA387 Grade 11 Class 2?
In its normalized and tempered condition, SA387 Grade 11 Class 2 provides a tensile strength of 485–620 MPa (70–90 ksi) and a minimum yield strength of 275 MPa (40 ksi), making it suitable for high-stress, elevated-temperature designs.
3. How does SA387 Grade 11 Class 2 differ from Class 1?
Class 2 is normalized and tempered for higher as-supplied strength, while Class 1 is annealed for maximum formability; both share the same chemical composition but are selected based on fabrication needs and design stress requirements.
4. What is the maximum service temperature for SA387 Grade 11 Class 2?
SA387 Grade 11 Class 2 is typically used in continuous service up to about 595 °C (1100 °F), where its chromium and molybdenum content provides effective resistance to oxidation and hydrogen attack.
5. What are common applications for SA387 Grade 11 Class 2 plates?
This grade is widely used in hydrotreaters, hydrocrackers, heat exchangers, and other high-temperature pressure vessels in petrochemical refineries and power-generation facilities.
6. What welding procedures are required for SA387 Grade 11 Class 2?
Welding requires low-hydrogen electrodes, preheating (150–205 °C / 300–400 °F), and mandatory post-weld heat treatment (PWHT) around 620–690 °C (1150–1275 °F) to prevent cracking and restore corrosion resistance.
7. What is the equivalent European grade for SA387 Grade 11 Class 2?
The closest European equivalent is 13CrMo4-5 (1.7335) under EN 10028-2, which has similar composition and is commonly supplied in a normalized and tempered condition.
8. How does SA387 Grade 11 Class 2 compare to Grade 22?
Grade 11 (1.25Cr-0.5Mo) offers lower high-temperature strength and hydrogen resistance than Grade 22 (2.25Cr-1Mo), making it a cost-effective choice for moderate‑severity service in refining and chemical processes.
9. What are the Charpy impact requirements for SA387 Grade 11 Class 2?
Charpy V‑notch impact testing is often specified by purchasers; common requirements are 20 J (15 ft‑lb) minimum average at temperatures between +10 °F and –20 °F (–12 °C to –29 °C) for pressure‑vessel applications.
10. What is the difference between SA387 Grade 11 Class 2 and AISI 4130?
While both are Cr‑Mo steels, SA387 Grade 11 Class 2 is a plate product for code pressure vessels with strict toughness and testing rules, whereas AISI 4130 is a general‑purpose structural/bar alloy with different property ranges and applications.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
