1. What is ASTM A671 CJB115 Class 40 Steel Pipe?
Answer: ASTM A671 CJB115 Class 40 is a high-performance electric-fusion-welded (EFW) carbon steel pipe designed for ultra-critical high-pressure applications (service temperature above -20°F/-29°C). The "Class 40" designation indicates a minimum yield strength of 40 ksi (276 MPa), making it suitable for extreme industrial pressure systems.
2. Key Material Properties?
Answer:
Mechanical:
Yield Strength: ≥40 ksi (276 MPa)
Tensile Strength: 110-130 ksi (759-896 MPa)
Impact Test: Mandatory (Charpy V-notch at operating temperature)
Chemical:
Carbon (C): ≤0.35% (optimized for weldability)
Manganese (Mn): 1.35-1.65% (enhanced strength)
P/S: ≤0.020% (strict impurity control)
3. Typical Applications?
Answer:
Nuclear power plant primary coolant lines
Offshore oil & gas high-pressure risers (10,000+ psi)
Aerospace hydraulic test systems
Heavy industrial forging presses
4. How does it compare to Class 35 and Class 45?
Answer:
| Class | Yield Strength | Key Difference |
|---|---|---|
| Class 35 | 35 ksi (241 MPa) | High-pressure standard |
| Class 40 | 40 ksi (276 MPa) | Ultra-high-pressure premium grade |
| Class 45 | 45 ksi (310 MPa) | Specialized extreme applications |
5. Fabrication Requirements?
Answer:
Welding: Preheat (450°F min.) + PWHT (1200-1300°F) + 100% X-ray inspection
Testing: Hydrostatic (3.5x design pressure) + hardness mapping
Forming: Hot forming only (cold bending prohibited)
Certification: Nuclear-grade documentation (ASME NQA-1 compliant)
