SA 387 Grade 22 Class 2 is a low-alloy chromium-molybdenum steel plate for pressure vessels, widely used in high-temperature and high-pressure environments, compliant with ASTM standards, offering excellent heat resistance and weldability.
SA 387 GR.22 Equivalent Grades :
| BS | ASTM/ASME | UNS | EN | DIN |
| 622-515B | A387 / SA 387 | K21590 | 10 CRMO 910 | 10 CRMO 910 |
Chemical Composition of SA387 GR.22 CL.2 Plate
| C | Mn | P | S | Si | Cr | Mo |
| 0.04 - 0.15 | 0.25 - 0.66 | 0.035 | 0.035 | 0.5 max | 1.88 - 2.62 | 0.85 - 1.15 |
Mechanical Properties of SA 387 GR.22 CL.2 Plate
| Tensile Strength | Yield Strength | Elongationin 50mm (%) | Reduction of area in % |
| 75-100 ksi, 515-690 MPa | 45 Ksi, 310 MPa | 18 | 45 |
processing
1. Melting and Refining
Produced by electric arc furnace (EAF) plus LF (ladle furnace) and VD (vacuum degassing) to ensure high purity.
Strict control of chemical composition to meet ASME SA-387 requirements.
Key elements: C 0.05–0.15%, Cr 2.00–2.50%, Mo 0.90–1.10%, P and S ≤ 0.025%.
2. Hot Working (Rolling / Forming)
Heating: Reheat ingots or billets to 1210–1270°C with 6–9 hours holding time for homogenization.
Rolling: Start rolling at 1040–1160°C, finish rolling at 800–850°C.
Controlled cooling: After rolling, slow cooling in insulated piles above 500°C for 70–80 hours to prevent cracking and ensure uniform microstructure.
Hot forming (e.g., heads): Heat to 930–960°C, hold 1.0–1.5 min/mm, then air cool.
3. Heat Treatment
Normalizing + Tempering (required for delivery):
Normalizing at 900–960°C, air cooled.
Tempering at 680–750°C, air cooled.
Target microstructure: ≥90% bainite.
Quenching + Tempering (optional):
Quenching at 900–930°C, water cooled.
Tempering at 710–750°C.
Simulated Post-Weld Heat Treatment (PWHT): 690 ± 14°C, holding time based on thickness (typically 8–26 hours).
4. Welding
Use low-hydrogen electrodes or welding wires.
Preheat temperature: typically 200–300°C (varies with thickness).
Interpass temperature: ≤350°C.
Post-Weld Heat Treatment (PWHT): 675–705°C, minimum holding time based on material thickness.
5. Machining and Fabrication
Good machinability in the normalized and tempered condition.
Use sharp tools and moderate cutting speeds.
Avoid overheating during machining to prevent softening.
6. Inspection and Testing
Ultrasonic testing (UT) for plates.
Tensile, impact, and hardness tests.
Microstructure examination.
Hydrogen-induced cracking (HIC) testing if required for sour service.
General Industrial Applications
Pressure vessels and tanks in refineries and petrochemical plants
Reactors, columns, and heat exchangers operating at elevated temperatures and pressures
Boilers, superheaters, and headers in power boilers and waste heat recovery boilers
Piping components (pipe supports, flanges, and fittings) in high-temperature service
Pressure vessel plates for hydrogenation units, hydrocracking units, and hydrotreating units
Key Application Areas
1. Oil Refining and Petrochemical
Hydrotreaters and hydrocrackers (reactors, furnace tubes, and associated vessels)
Reformers, isomerization units, and other hydrogen-containing process units
Amine treaters, sulfur recovery units, and other high-temperature process equipment
2. Power Generation
Boiler pressure parts in thermal power plants (water walls, headers, and steam drums)
Components in combined cycle power plants (heat recovery steam generators, HRSG)
Nuclear power plant auxiliary systems (non-nuclear pressure vessels and heat exchangers)
3. Chemical and Process Industry
Chemical reactors for high-temperature and high-pressure processes
Heat exchangers and condensers handling hot oil, steam, or process fluids
Pressure vessels for hydrogen, ammonia, methanol, and other chemical synthesis processes
4. Other Special Applications
Sour service equipment (with appropriate HIC/SCC testing and controls)
Offshore and onshore oil & gas processing equipment
High-temperature storage tanks and pressure vessels in various industrial sectors
Get an valued quotation for SA 387 Grade 22 Class 2, Contact GNEE Steel.
What is the main alloy composition of SA 387 Grade 22 Class 2?
Its core components are iron, 2.25% chromium, and 1% molybdenum. Trace elements like carbon and manganese are added to enhance mechanical properties and structural stability.
What post-weld heat treatment (PWHT) is required for SA 387 Grade 22 Class 2?
Common PWHT is tempering at 620-675°C, held for sufficient time to relieve residual stresses, enhance ductility, and restore material performance after welding.
What are the surface finish requirements for SA 387 Grade 22 Class 2?
The surface should be free of cracks, scratches, and contaminants. It is usually supplied with a pickled or blasted finish for better weldability and coating adhesion.
What is the tensile strength of SA 387 Grade 22 Class 2 at elevated temperatures?
At 500°C, its tensile strength is about 250 MPa, gradually decreasing with rising temperature but remaining sufficient for designed high-temp loads.
What industries mainly use SA 387 Grade 22 Class 2?
It is widely used in oil and gas, petrochemical, power generation (boilers, turbines), and chemical processing industries for pressure vessels and pipelines.
Does SA 387 Grade 22 Class 2 have good corrosion resistance?
It has moderate corrosion resistance to oxidation and hydrogen at high temps. For severe corrosive media, additional coating or alloying is needed.
What is the heat treatment process for SA 387 Grade 22 Class 2?
Typically normalized (890-940°C) and tempered (620-675°C) to refine grain structure, improve strength, toughness, and dimensional stability.
Can SA 387 Grade 22 Class 2 be formed by bending or rolling?
Yes, it has good formability. Hot forming (above 900°C) is recommended for thick plates; cold forming is feasible with proper stress relief afterward.
Can SA 387 Grade 22 Class 2 be used in low-temperature environments?
It is not ideal for low temps below -29°C. Its toughness decreases at low temperatures; other grades like SA 387 Grade 11 are preferred for cryogenic conditions.
Which ASTM standard governs SA 387 Grade 22 Class 2?
It is regulated by ASTM A387/A387M, a standard specifying low-alloy steel plates for pressure vessels operating at elevated temperatures and pressures.