A537 CL 3 (Class 3) refers to a specific type of heat-treated, carbon-manganese-silicon steel plate, defined by ASTM A537/A537M, used for making fusion-welded pressure vessels and structures, offering higher strength than Class 1 or 2, with a minimum yield strength of 55 ksi (380 MPa) for thinner plates, achieved through quenching and tempering. It's a robust material suitable for demanding applications in the oil, gas, and chemical industries.
The chemical composition of ASTM A537 Class3,by mass %
| Grade | C | Si | Mn | P | S | Cu | Ni | Cr | Mo |
| A537CL3 | 0.24 | 0.13- 0.55 |
0.64- 1.46 |
0.035 | 0.035 | 0.38 | 0.28 | 0.29 | 0.09 |
The mechanical properties of ASTM A537 Class3
| Grade | Thickness (mm) |
Yield strength Min [MPa] |
Tensile strength [MPa] |
Elongation [%] |
| A537Cl3 | 8-65 | 380 | 550-690 | 22 |
| 66-100 | 345 | 515-655 | 22 | |
| 101-150 | 275 | 485-620 | 20 |
Applications
Pressure Vessels & Boilers: Used in power plants, chemical processing, and energy facilities for components requiring reliable performance under pressure.
Storage Tanks: Ideal for industrial storage tanks, including those for API 650/620 standards.
Heat Exchangers: Suitable for components within heat exchange systems.
Oil & Gas Industry: Found in separators, reactors, and other equipment in demanding upstream and downstream operations.
If you have project requirements for ASTM A537 Class3, 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 the equivalent of ASTM A537 cl3?
The equivalent of ASTM A537 Class 3 (a quenched and tempered steel for pressure vessels) includes ASME SA537 Class 3, European EN 10028-3 P420NH, German DIN 17102 WStE355, and Japanese JIS G3115 SPV450, all offering similar high strength and toughness for demanding applications. These grades are interchangeable for many projects, but always verify with project specifications.
2.Is astm a537 class 3 better than class 1 ?
Yes, ASTM A537 Class 3 is generally considered "better" or more advanced than Class 1 because its quenched and tempered (Q&T) heat treatment provides significantly improved strength and superior notch toughness, especially for low-temperature service in pressure vessels, whereas Class 1 is only normalized, offering lower strength but consistent properties for less demanding applications. Class 3 offers higher yield and tensile strength, balancing high strength with enhanced toughness that Class 1 lacks, making it suitable for more severe service conditions.
3.What is the latest edition of ASTM A537?
Latest Edition: ASTM A537/A537M – 20 (Reapproved 2020) Effective: November 1, 2020. Replaces: A537/A537M – 13. No amendments as of November 16, 2025.