1. What is ASTM A671 CJB115 Class 20 steel pipe?
ASTM A671 CJB115 Class 20 is an electric-fusion-welded (EFW) carbon steel pipehigh-pressure industrial applications (typically operating above -20℃F/-29℃). The "Class 20" designation indicates a minimum yield strength of 20 ksi (138 MPa), making it suitable for demanding pressure systems in industrial settings.
2. Key specifications and material properties?
CJB115 carbon steel (higher carbon content than CJA grades)
>=20 ksi (138 MPa)
70-90 ksi (483-621 MPa)
Required only for specified low-temperature applications
Carbon (C): <=0.35%
Manganese (Mn): <=1.35%
Phosphorus/Sulfur (P/S): <=0.035%
3. Typical industrial applications?
High-pressure fluid transport
4. How does it compare to adjacent classes?
| 15 | 15 ksi | Medium-high pressure |
| 20 | 20 ksi | High-pressure industrial |
| 25 | 25 ksi | Special high-pressure systems |
5. Fabrication and quality control requirements?
Preheat (200-300°F) required for thickness >1" (25.4 mm)
Hydrostatic test at 1.5x design pressure + optional NDE
Full compliance with ASTM A671-26 standards
