What are the equivalent materials to SA387 Grade 22 Class 1?
SA387 Grade 22 Class 1
SA387 Grade 22 Class 1 is an annealed 2.25Cr-1Mo alloy steel plate designed for high-temperature pressure vessels, supplied in a softened condition to provide maximum ductility and formability for complex fabrication before final post-weld heat treatment establishes its service strength.
The direct international equivalents for SA387 Grade 22 Class 1 are materials that match its 2.25Cr-1Mo composition and are intended for similar annealed, pressure vessel applications. However, full equivalency is only valid when the material condition (annealed) and certification (pressure vessel plate standard) are confirmed.
| Standard / Region | Equivalent Designation | Critical Note on Equivalency |
|---|---|---|
| ASME (USA) | SA387 Grade 22 Class 1 | The mandatory code specification. Any equivalent must ultimately meet this for ASME stamp vessels. |
| UNS (USA) | K21590 | Unified Numbering System identifier for the 2.25Cr-1Mo composition. |
| EN / DIN (Europe) | 10CrMo9-10 (1.7380) | The closest European pressure vessel steel under EN 10028-2. It is a functional equivalent, but its specified composition range and properties are not identical. It is commonly used in similar applications. |
| GB (China) | 12Cr2Mo1R | The Chinese pressure vessel plate standard. The "R" denotes container/vessel steel. This is a very common equivalent in Asian projects. |
| Common Alloy Name | 2¼Cr-1Mo or 2.25Cr-1Mo | The universal industry shorthand based on its nominal composition. |
Critical Distinctions for Proper Equivalency
1."Class 1" (Annealed) is Essential: Most generic references to "Grade 22" or "2.25Cr-1Mo" assume the normalized and tempered (Class 2) condition, which is the most common. You must specify "Class 1" or "Annealed Condition" to get the correct, softer material. The European 10CrMo9-10 is typically supplied in a normalized and tempered or normalized condition, so an annealed heat treatment must be specifically requested.
2.Material Standard Defines the Product: An equivalent must come from a pressure vessel plate standard, not a general structural standard. For example:
Correct: EN 10028-2 (Flat products for pressure purposes).
Not a Direct Equivalent: A bar or forging standard with similar chemistry (e.g., AISI 422, A182 F22). These have different property requirements and manufacturing processes.
3.The Role of Certification: For an ASME Code pressure vessel, the plate must be certified as meeting SA387. A plate meeting only 10CrMo9-10 or 12Cr2Mo1R may require additional testing and verification by the manufacturer to be accepted as an SA387 equivalent under ASME Code Case or the user's Material Manufacturer's Certificate.
Summary of Recommended Approach
For procurement and engineering:
1.Primary Specified Material: SA387 Grade 22 Class 1 (Annealed).
2.Common Acceptable Substitute (if approved): EN 10028-2: 10CrMo9-10 supplied in annealed (+A) condition.
3.Common Acceptable Substitute (Asia-focused): GB 713: 12Cr2Mo1R supplied in annealed condition.
Always verify that the proposed equivalent's heat treatment condition, mechanical properties at room and elevated temperature, and certification meet the specific design requirements of your project. The final authority for equivalency in code work rests with the project's responsible engineer and the Authorized Inspector.
What is SA387 Grade 22 Class 1?
SA387 Grade 22 Class 1 is an annealed chromium-molybdenum alloy steel plate designed for high-temperature pressure vessel service, with a composition of 2.25% Cr and 1% Mo to resist oxidation and hydrogen attack in refinery and power plant applications.
What are the mechanical properties of SA387 Grade 22 Class 1?
In its annealed condition, SA387 Grade 22 Class 1 typically has a tensile strength of 415-585 MPa (60-85 ksi), a minimum yield strength of 205 MPa (30 ksi), and high ductility, making it suitable for severe forming before final heat treatment.
Where is SA387 Grade 22 Class 1 commonly used?
It is widely used in hydroprocessing reactors, hydrocrackers, heat exchangers, and high-temperature pressure vessels in the petrochemical and power generation industries, especially where resistance to hydrogen attack and creep is required.
How does SA387 Grade 22 Class 1 differ from Class 2?
Class 1 is supplied in an annealed state for better formability, while Class 2 is normalized and tempered for higher as-delivered strength. Class 1 is chosen when complex fabrication is needed before final PWHT.
What is the post-weld heat treatment (PWHT) for SA387 Grade 22 Class 1?
PWHT is mandatory and typically performed at 1250-1300°F (675-705°C) to relieve welding stresses, prevent hydrogen-induced cracking, and restore corrosion resistance in the weld zone for high-temperature service.
What are the equivalent materials to SA387 Grade 22 Class 1?
Common equivalents include UNS K21590, European 10CrMo9-10 (1.7380), and the generic designation 2.25Cr-1Mo steel. However, exact equivalency depends on heat treatment and certification requirements.
Can SA387 Grade 22 Class 1 be used in hydrogen service?
Yes, its 2.25% chromium and 1% molybdenum content provides excellent resistance to high-temperature hydrogen attack (HTHA), making it a standard choice for hydrogen processing units in refineries.
What are the forming and machining guidelines for SA387 Grade 22 Class 1?
Due to its annealed condition, it offers good cold formability but requires preheating for hot forming and controlled machining to avoid excessive work hardening, with tooling suitable for alloy steels.
What standards certify SA387 Grade 22 Class 1 plates?
Plates are certified to ASME SA387/SA387M and ASTM A387/A387M standards, with mill test reports (MTRs) providing chemical and mechanical properties per EN 10204 3.1 or 3.2.
How does SA387 Grade 22 Class 1 compare to Grade 11 or Grade 5?
Compared to lower-alloy grades like Grade 11 (1.25Cr-0.5Mo) or Grade 5 (5Cr-0.5Mo), Grade 22 offers superior high-temperature strength and hydrogen resistance, but requires stricter welding and heat treatment controls.
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.
