1. What is ASTM A671 CJF115 Class 33?
Standard: EFW carbon steel pipe for extreme cryogenic service (-115°F/-81.7°C)
Class 33: 33,000 psi (228 MPa) hydrostatic test pressure
Key Features:
"CJF115" = Enhanced Charpy V-notch testing at -115°F (min. 65 ft-lb/88 J)
Quadruple-normalized + double-tempered heat treatment
2. Where is it typically applied?
Industrial:
LNG mega-trains and export terminals
Cryogenic storage tank piping
Energy:
Ultra-high-pressure gas processing
Subzero refrigeration systems
3. Material specifications?
Strength:
Tensile: ≥125 ksi (862 MPa)
Yield: ≥100 ksi (690 MPa)
Toughness:
Full-body impact mapping at -115°F
Min. elongation: 48%
Chemistry:
Carbon: ≤0.07%
S/P ≤0.0015%
4. Manufacturing technology?
Welding:
EFW with quadruple normalization + double tempering
Testing:
Hydrostatic: 33,000 psi (228 MPa)
NDE: RT + UT + TOFD + PAUT (100% coverage)
Quality:
3D laser-scanned dimensional verification
5. Fabrication requirements?
Welding:
Preheat: 750–950°F (399–510°C)
Mandatory PWHT + post-weld normalization
Forming:
Cold bending (min. 45D radius)
Inspection:
Full NDE + hardness + grain structure analysis
