1. What is ASTM A671 CJE115 Class 22?
Standard: Electric-fusion-welded (EFW) carbon steel pipe for ultra-high-pressure cryogenic service (-115°F/-81.7°C).
Class 22: Hydrostatic test pressure of 22,000 psi (152 MPa) (highest tier in A671 standard).
Key Identifier:
"CJE115" = Charpy V-notch impact tested at -115°F with min. 15 ft-lb (20 J).
Mandatory normalization for grain refinement.
2. Where is it primarily used?
Extreme-pressure cryogenics:
LNG carrier containment systems
Liquid hydrogen transport pipelines
Specialty energy:
Deepwater oil & gas risers
Arctic pressure vessels
Nuclear auxiliary systems: Cryogenic coolant loops
3. Mechanical & chemical properties?
Strength:
Tensile: ≥60 ksi (414 MPa)
Yield: ≥35 ksi (241 MPa)
Toughness:
100% impact testing at -115°F
Elongation: ≥22% (scaled per thickness)
Chemistry:
Carbon: ≤0.30%
Low S/P (≤0.035% each)
4. Manufacturing requirements?
Welding:
EFW with 100% radiography (RT) + UT for full-length seams.
Testing:
Hydrostatic pressure: 22,000 psi (152 MPa)
Supplemental NDE (MT/PT) for critical zones.
Traceability:
Heat-specific impact test reports.
5. Fabrication guidelines?
Welding:
Preheat: 200–400°F (93–204°C)
PWHT required for thickness >1.5" (38 mm).
Forming:
Cold bending allowed (min. 5D radius).
Hot forming requires re-normalization.
Repairs:
Grinding depth ≤10% wall thickness (per ASTM A671 Sec.12).
