What is ASTM A387 Grade 11 equivalent to?
ASTM A387 Grade 11 Class 1 refers to a chromium-molybdenum (1.25% Cr, 0.5% Mo) alloy steel plate for pressure vessels supplied in the normalized or stress-relieved heat treatment condition. It is designed for high-temperature service where the fabricator will perform final post-weld heat treatment (PWHT) after manufacturing, making it suitable for components requiring extensive forming and welding in refineries and power plants.
ASTM A387 Grade 11 has widely recognized international and industry equivalents, though exact equivalence depends on the specific standard and application context (e.g., pressure vessel code, piping code, forging specification).
1. Closest International Material Standards (Near-Identical Composition & Application)
These are the most direct equivalents for pressure vessel plate applications:
EN 10028-2: 13CrMo4-5 (European Standard)
This is the most common and precise European equivalent. It has an almost identical chemical composition range (1.0-1.5% Cr, 0.4-0.6% Mo) and is designated for pressure purposes.
JIS G3115: SCMV 430 (Japanese Industrial Standard)
GB 713: 15CrMoR (Chinese Standard for Pressure Vessel Steel)
Note: While equivalent, 15CrMoR typically has a slightly higher nominal chromium content (around 1.5%).
2. Key U.S. Industry & Manufacturer Specifications
These standards cover the same alloy but under different product forms or specific industry codes:
ASME SA-387 Grade 11
When the ASTM specification is adopted by the ASME Boiler and Pressure Vessel Code for safety-critical applications, it is prefixed with an 'S' (e.g., SA-387). The composition and requirements are essentially identical.
ASTM A335 P11 / ASME SA335 P11 (for Seamless Pipe)
ASTM A182 F11 / ASME SA182 F11 (for Forgings & Fittings)
Important: Within A182, F11 Class 1 is the normalized grade, while F11 Class 2 is the normalized and tempered grade. This aligns with the A387 Class 1 vs. Class 2 philosophy.
ASTM A213 T11 (for Seamless Tubes)
UNS K11789
This is the Unified Numbering System identifier for this specific alloy composition.
3. Comparison Table of Common Equivalents
| Standard & Form | Grade Designation | Typical Application | |
|---|---|---|---|
| Plate (Pressure Vessel) | ASTM A387 / ASME SA387 | Gr. 11, Cl.1 / Cl.2 | Vessels, Reactors, Drums |
| European Plate | EN 10028-2 | 13CrMo4-5 | Same as A387 |
| Chinese Plate | GB 713 | 15CrMoR | Same as A387 |
| Seamless Pipe | ASTM A335 / ASME SA335 | P11 | High-temperature piping |
| Forgings & Fittings | ASTM A182 / ASME SA182 | F11 | Flanges, elbows, valves |
| Seamless Tube | ASTM A213 / ASME SA213 | T11 | Boiler tubes, heat exchangers |
| Generic Alloy | UNS | K11789 | Cross-reference identification |
Critical Consideration: "Equivalent" Does Not Mean "Freely Interchangeable"
While these materials are chemically similar, they are not automatically substitutable in a design. Key factors must be verified:
Governing Code: The project specification (e.g., ASME Section VIII, EN 13445) dictates which material standards are permissible.
Specific Requirements: Minimum strength, impact testing (Charpy), heat treatment condition (Class 1 vs. Class 2), and permissible trace elements can vary between standards.
Product Form: The properties of a plate (A387) are different from a forging (A182) due to manufacturing processes.
Conclusion: The primary global equivalent for ASTM A387 Grade 11 plate is EN 10028-2 13CrMo4-5. For other product forms in U.S. standards, the equivalent grades are A335 P11 (pipe), A182 F11 (forgings), and A213 T11 (tube). Any substitution must be approved by the responsible engineer and comply with the applicable construction code and original design calculations.
What is A387 grade 11 material?
The ASTM A387 specification is the Standard Specification for Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum intended primarily for use in welded boilers and pressure vessels designed for elevated temperature service. SSAB can supply A387 Grade 11 to the tension test requirements for Class 1 and/or Class 2.
What is the composition of A387 steel?
Composition: ASTM A387 steel plates typically contain chromium (up to 9% or more) and molybdenum (up to 2.25% or more), which enhance their strength and corrosion resistance at high temperatures.
What is the difference between A182 and A387?
Both ASTM A182 grade F11 class 2 and ASTM A387 grade 22 steel are iron alloys. They have a very high 99% of their average alloy composition in common. There are 32 material properties with values for both materials. Properties with values for just one material (1, in this case) are not shown.
What is ASTM A387 Grade 11 equivalent to?
ASTM A387 grade 11 equivalent steel is ASME SA387 grade 11. ASTM A387 grade 11 covers A387 grade 11 class 1 and A387 grade 11 class 2, which are equivalent to ASME SA387 grade 11 class 1 and SA387 grade 11 class 2 respectively.
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.
