SA387 Grade 22 steel plate, also known as ASTM A387 Grade 22 or ASME SA387 Grade 22, is a chromium-molybdenum (chrom-moly) steel plate used for boilers and pressure vessels that operate at high temperatures and pressures.
SA387 Grade 22 Class 1 is a Chromium-Molybdenum (Cr-Mo) alloy steel plate (ASME/ASTM standard) designed for high-temperature pressure vessels and boilers, known for excellent weldability, high-temperature strength, and corrosion resistance, especially in sour (sulfide) gas environments.
SA387 Grade 22 Class 2 is a chromium-molybdenum (chrome-moly) alloy steel plate, specified by ASME (SA) for weldable pressure vessels and boilers used in high-temperature service, offering excellent corrosion/oxidation resistance, high strength (75-100 ksi tensile), and good low-temperature toughness, essential for the oil, gas, and chemical industries.
Key Differences Summarized:
Heat Treatment: Class 2 often involves a more controlled heat treatment process (like quenching and tempering or just more rigorous normalising) than Class 1, which can be simpler.
Strength: Class 2 always offers higher tensile strength and yield strength than Class 1 for the same SA387 grade (e.g., Gr 11, Gr 22).
Ductility (Elongation): Class 1 typically has slightly higher elongation values (better ductility) compared to Class 2, which sacrifices some ductility for increased strength.
Applications: Class 2 is preferred for critical high-temperature service or higher pressure requirements, while Class 1 might be used where less extreme conditions prevail.
Chemical Composition
Both classes are Grade 22 (2.25% Chromium, 1% Molybdenum) and share the same general limits for elements like Carbon, Manganese, Phosphorus, Sulfur, and Silicon, with only slight variations in ranges for product analysis.
If you have project requirements for SA387 Grade 22 Class 1&2 , we welcome your inquiry. GNEE maintains a large inventory of commonly used high strength steel grades for your selection.For detailed mechanical properties, chemical composition, and technical data, as well as free samples, please contact our factory immediately. We offer competitive prices, stable quality, and professional service. Email:beam@gneesteelgroup.com.
1.What is SA 387 GR 22 material?
The SA 387 Grade 22 Steel is a pressure vessel steel made up of high-quality raw material and high technology. Commonly used for high-temperature tasks based on its high heat tolerance this steel plate can be exposed up to 600° while maintaining superb oxidation and corrosion resistance.
2.What is the difference between Class 1 and Class 2 steel?
Class 1 is normalized, with a tensile strength of 70-90 ksi and a minimum yield of 50 ksi. Class 2 has a tensile strength of 80-100 ksi and minimum yield strength of 60 ksi.