What is ASTM A387 Gr.22?
ASTM A387 Grade 22 (UNS K21590) is a 2.25Cr‑1Mo heat-resistant alloy steel plate governed by ASTM A387 / ASME SA387 specifications. It is available in Class 1 and Class 2, with Class 2 being the dominant commercial grade supplied in mandatory normalized and tempered (N+T) condition. Engineered for high-temperature, high-pressure, hydrogen-rich and sour corrosive service, it is the globally qualified material for hydrogenation reactors, high-temperature heat exchangers, steam headers and refinery desulfurization equipment.
What is 12Cr2Mo1R?
12Cr2Mo1R is a special pressure vessel steel plate complying with China's GB/T 713.2-2023 standard, serving as the domestic equivalent grade of ASTM A387 Gr.22. It conforms to Chinese special equipment codes for boilers and pressure vessels, featuring mature domestic mass production, shorter lead time and superior cost performance. It is widely applied in domestic petrochemical, thermal power and high-pressure pressure vessel manufacturing.
If you are sourcing Cr-Mo alloy plates for pressure vessel projects, send your technical specification and drawing to us to receive a custom quotation within 24 hours.
Core Performance Difference (Take Class 2 As an Example)
ASTM A387 Gr.22 CL2 and 12Cr2Mo1R are equivalent 2.25Cr-1Mo chromium-molybdenum alloy steels with highly consistent chemical composition and basic mechanical properties. Nevertheless, differences in manufacturing standards, heat treatment regulations and inspection criteria lead to distinct performance gaps under extreme service conditions.
Low-Temperature Toughness
ASTM A387 Gr.22 CL2 can be supplied with Charpy V-notch impact testing at -52℃ as per Supplementary Requirement S5, providing excellent low-temperature fracture resistance for cold start-up and low ambient temperature service. 12Cr2Mo1R is normally tested at -20℃ / -40℃ with limited low-temperature toughness.
High-Temperature Creep Stability
ASTM A387 Gr.22 CL2 has official ASME-certified high-temperature creep data and a fixed minimum tempering temperature of 677℃, maintaining stable microstructure during long-term service at 550–600℃ and repeated thermal cycling. 12Cr2Mo1R performs steadily under static high-temperature conditions but lacks internationally recognized creep certification, making it ineligible for ASME-standard high-temperature design verification.
Temper Embrittlement Resistance
12Cr2Mo1R implements stricter control over P and S impurities, delivering superior resistance to temper embrittlement under stable static high-temperature service. ASTM A387 Gr.22 CL2 adopts standardized heat treatment processes, offering stronger adaptability to fluctuating temperatures and frequent thermal cycles.
Hydrogen & Sour Corrosion Resistance
ASTM A387 Gr.22 CL2 is commonly accepted for sour service in accordance with NACE MR0175 / ISO 15156-2 (hardness controlled), and optional HIC / SSCC testing per NACE TM0284 / TM0177 can be performed on a project basis. 12Cr2Mo1R supports customized corrosion testing but holds no international certification.
Welding & PWHT Adaptability
12Cr2Mo1R features a wider post-weld heat treatment window, lower welding cracking risk and higher construction tolerance for domestic fabrication. ASTM A387 Gr.22 CL2 enforces a fixed 677℃ minimum tempering temperature and strict process control, guaranteeing consistent performance for high-standard international manufacturing.
International Certification Compatibility
ASTM A387 Gr.22 CL2 is fully recognized by ASME U-Stamp, PED and API certifications, suitable for global export projects. 12Cr2Mo1R only complies with Chinese GB standards and is exclusively accepted for domestic pressure vessel projects.
Core Performance Difference: ASTM A387 Gr.22 CL2 vs 12Cr2Mo1R
|
Performance Dimension |
ASTM A387 Gr.22 CL2 |
12Cr2Mo1R |
|
Low-Temperature Toughness |
-52℃ mandatory impact test, excellent low-temperature performance |
-20℃/-40℃ conventional test, limited low-temperature toughness |
|
High-Temperature Creep Stability |
ASME certified, stable under high temperature & thermal cycles |
Stable for static high-temperature use, no international creep data |
|
Temper Embrittlement Resistance |
Strong thermal cycle adaptability |
Better anti-embrittlement for static high-temperature service |
|
Hydrogen & Sour Resistance |
NACE MR0175 certified, qualified for global hydrogen projects |
Custom test available, no international certification |
|
Welding & PWHT |
Fixed 677℃ tempering, strict standard process |
Wide PWHT window, low welding risk, high tolerance |
|
Certification Scope |
Global ASME/PED/API certified for export |
Only domestic GB standard compliance |
ASTM A387 Gr.22 Pressure Vessel Steel Plate Specification
| Item | Specification |
|---|---|
| Steel Grade & Standard |
ASTM A387 Grade 22 Class 1 / Class 2 ASME SA387 Grade 22 Class 1 / Class 2 |
| Supply Range |
Thickness: 5–250 mm (0.2–10 in) Width: 1,000–4,000 mm Length: 3,000–18,000 mm Custom sizes available upon request |
| Delivery Condition |
Class 1: Normalized (N) Class 2: Normalized and Tempered (N+T) Optional: Quenched & Tempered (Q&T) where specified by customer or project requirements |
Chemical Composition: ASTM A387 Gr.22 CL2 vs 12Cr2Mo1R
| Element (%) | ASTM A387 Gr.22 (heat analysis, per ASTM A387/A387M) | 12Cr2Mo1R (heat analysis, per GB/T 35012-2018 / GB/T 713.2-2023) |
|---|---|---|
| C | 0.05 – 0.15 | 0.08 – 0.15 |
| Si | ≤ 0.50 | ≤ 0.50 |
| Mn | 0.30 – 0.60 | 0.30 – 0.60 |
| P | ≤ 0.035 | ≤ 0.010 |
| S | ≤ 0.035 | ≤ 0.007 |
| Cr | 2.00 – 2.50 | 2.00 – 2.50 |
| Mo | 0.90 – 1.10 | 0.90 – 1.10 |
Mechanical Property: ASTM A387 Gr.22 CL2 vs 12Cr2Mo1R
| Property (standard minimum values) | ASTM A387 Gr.22 Class 2 (per ASTM A387/A387M) | 12Cr2Mo1R (per GB/T 713.2-2023, 6–200 mm) |
|---|---|---|
| Tensile strength | 515 – 690 MPa (75 – 100 ksi) | 520 – 680 MPa |
| Minimum yield strength | ≥ 310 MPa (45 ksi) | ≥ 310 MPa (ReL) |
| Elongation (50 mm gauge) | ≥ 18 % | ≥ 19 % |
| Charpy V-notch impact | Not mandatory in base spec; optional per Supplementary Requirement S5, temperature/energy per purchase order (commonly −50 °F ≈ −46 °C) | Hydrogen-service grade: −30 °C, KV2 ≥ 55 J per GB/T 35012-2018; other temperatures per design agreement |
Unsure which grade satisfies your design specification and third-party inspection requirements? Contact our engineering team for free material suitability assessment.
Heat Treatment Characteristics: ASTM A387 Gr.22 CL2 vs 12Cr2Mo1R
Both steel grades acquire excellent creep resistance via Normalized + Tempered (N+T) heat treatment. Heat treatment parameters directly determine the high-temperature service stability and anti-embrittlement performance of finished plates.
- Normalizing: 900–955℃ air cooling for uniform grain refinement
- Mandatory minimum tempering temperature:677℃ (strictly specified by ASTM standards)
- Simulated post-weld heat treatment (PWHT) test is available to ensure stable mechanical properties after cyclic welding thermal loads
- Suitable for long-term service under extreme high-temperature creep conditions of 550–600℃
- Normalizing: 920–960℃ air cooling
- Tempering range: 680–750℃ (no fixed minimum temperature, adjusted according to plate thickness)
- Delivers uniform microstructure and reliable stress relief effect
- Fully compliant with domestic long-term operation specifications for pressure vessel equipment
A387 Gr.22 and 12Cr2Mo1R Main Applications
Petrochemical Equipment: Widely used to manufacture critical pressure-bearing components such as hydrogenation reactors, coke drums, desulfurization vessels, synthesis gas waste heat boilers, methanators, and regenerators.
Power Station Boilers and the Power Industry: Used to manufacture boiler drums, high-temperature and high-pressure piping, headers, and high-pressure penstocks for hydroelectric power plants.
Nuclear Equipment Manufacturing: Serves as a key material for nuclear reactor pressure vessels, steam generators, and main steam piping.
Storage, Transport, and Separation Equipment: Suitable for manufacturing spherical tanks, oil and gas storage tanks, liquefied gas tanks, heat exchangers, and separators.
Selection Guide (How to Choose): ASTM A387 Gr.22 CL2 vs 12Cr2Mo1R
Choose ASTM A387 Gr.22 Class 2 if:
The equipment is intended for export or requires international pressure vessel certification
The equipment serves high-temperature, high-pressure, hydrogen-rich and low-temperature impact working conditions
Strict requirements apply for thermal cycle stability and long-term creep resistance
The technical agreement explicitly specifies ASTM/ASME standard materials by the end user
Choose 12Cr2Mo1R if:
Purely domestic thermal power, petrochemical and pressure vessel projects
No international certification or export compliance requirements
Cost-sensitive projects requiring fast production and delivery
Static high-temperature service without severe low-temperature impact or frequent thermal cycles
Can A387 Gr.22 and 12Cr2Mo1R Be Directly Interchanged?
Conditionally Allowed Substitution
For pure domestic projects without ASME certification and overseas delivery requirements, 12Cr2Mo1R can substitute A387 Gr.22 CL2 with official written approval from the design institute and end user, delivering lower procurement cost and shorter production lead time.
Strictly Prohibited Direct Replacement
Export equipment requiring ASME U-Stamp, PED or API third-party inspection
High-risk petrochemical hydrogenation and sour gas equipment specified by international licensors
Projects designed based on ASME high-temperature creep allowable stress data
Equipment operating under low-temperature environments or frequent thermal cycling conditions
Why Choose GNEE Steel?
1. Material Supply & Customization Service
Supply standard & non-standard pressure vessel steel plates complying with ASTM / ASME / GB / EN specifications, including A387 Gr.22 Class 2, A387 Gr.11, 12Cr2Mo1R, A516, SA537 etc.
Flexible size customization: customized thickness, width and length as per project drawings; support small trial orders and bulk project orders.
Control delivery status: normalized & tempered (N+T), quenched & tempered or as-rolled upon client requirements.
Large spot inventory for common sizes to shorten lead time for urgent projects.
2. Professional Steel Processing Service
Multi-mode precision cutting: laser cutting, flame cutting, plasma cutting and saw cutting for thick alloy plates.
Secondary machining: edge bevelling, grooving, drilling, deburring, surface grinding.
Surface treatment: shot blasting, anti-rust coating, export protective painting.
Process raw plates into finished blanks to reduce customers'on-site fabrication workload.
3. Complete Testing & Documentation Support
In-house lab testing: chemical analysis, tensile test, Charpy V-notch impact test, hardness inspection.
Mandatory ultrasonic testing (UT) per ASTM A435 / A578 or JB/T 4730 standards.
Optional advanced testing: HIC, SSCC, simulated PWHT test, Z-direction tensile test for high-risk hydrogen service.
Issue official Mill Test Certificate (MTC) conforming to EN 10204 3.1 / 3.2.
Support third-party witness inspection by SGS, BV, TÜV before loading.
Ready to source ASTM A387 Gr.22 or 12Cr2Mo1R plates? Submit your specification sheet, and our sales team will provide competitive pricing and reliable delivery schedule promptly.
FAQ
Q: Is 12Cr2Mo1R the same steel as ASTM A387 Gr.22?
A: Not exactly. The base chemistry is close (both are 2.25Cr-1Mo family), but the two grades are governed by different standards - ASTM A387/A387M (ASME SA-387) versus GB/T 35012-2018, now GB/T 713.2-2023 - with different heat treatment rules, supplementary testing and certification. "Equivalent" describes similar suitability for the same service class; it is not a guarantee of identical specification compliance.
Q: Can 12Cr2Mo1R replace A387 Gr.22 Class 2 in a hydrogenation reactor?
A: Only for projects designed under Chinese codes, and only with written approval from the design institute and the end user. For ASME-, PED- or API-certified equipment, or designs using ASME creep allowable stresses, the specified ASTM/ASME grade must be used. The mapping should be documented in the material traceability file.
Q: What is the minimum tempering temperature for A387 Gr.22 Class 2?
A: Per ASTM A387/A387M, Class 2 plates are normalized and then tempered at a minimum tempering temperature of 1250 °F (about 677 °C). This fixed minimum is one of the standard's key process controls.
Q: What are the tensile requirements for 12Cr2Mo1R?
A: Per GB/T 35012-2018 (now GB/T 713.2-2023), for 6–200 mm plate in the normalized-and-tempered condition: tensile strength 520–680 MPa, minimum yield strength (ReL) 310 MPa, minimum elongation 19 %. The hydrogen-service grade adds Charpy V-notch testing at −30 °C with KV2 ≥55 J and temper-embrittlement controls (J ≤100, X ≤15 ppm).
