1. What is A671 CJA115 Class 51 Steel Pipe?
Answer:
The A671 CJA115 Class 51 is the pinnacle of electric-fusion-welded carbon steel pipe technology under ASTM A671, engineered for ultra-low-temperature service (-75°F/-60°C) and record-high-pressure applications (51,000 psi hydrostatic test). Its "CJA115" grade (aligned with ASTM A537 Class 1) ensures unmatched performance for mission-critical infrastructure in extreme environments.
2. Governing Standards & Key Specifications?
Answer:
Standard: ASTM A671 (EFW pipes for low-temperature service).
Material: CJA115 (C≤0.24%, Mn 0.70–1.35%, P/S≤0.025%).
Testing:
100% automated UT/RT + Charpy V-notch at -75°F.
51,000 psi hydrostatic test (industry-leading).
Dimensions: Typical OD 16"–160", wall thickness optimized for stress loads.
3. Key Mechanical Properties?
| Property | Value |
|---|---|
| Tensile Strength | ≥ 80 ksi (550 MPa) |
| Yield Strength | ≥ 50 ksi (345 MPa) |
| Impact Toughness | > 45J at -75°F (-60°C) |
| Pressure Capacity | 51,000 psi (3,517 bar) |
4. Typical Applications?
Energy:
Ultra-deepwater pipelines (>7,000m depth).
Cryogenic hydrogen/LNG transport (-196°C).
Aerospace:
Rocket propellant containment (LOX/LH2).
Nuclear:
Advanced reactor coolant systems.
5. How Does Class 51 Compare to Class 50?
| Parameter | Class 51 | Class 50 |
|---|---|---|
| Pressure Rating | 51,000 psi | 50,000 psi |
| Design Focus | Next-gen applications | Current high-demand |
| Cost Premium | ~8–12% higher | Baseline |
