ASTM A671 CJP 115 Class 13 Steel Pipe

1. What distinguishes ASTM A671 CJP115 Class 13?

A high-pressure variant of electric-fusion-welded carbon steel pipe for cryogenic service:

CJP115: Specifies chemical composition (C≤0.30%, Mn≤1.20%) and -115°F (-82°C) impact testing

Class 13: Requires 1,300 psi (8.96 MPa) hydrostatic test pressure (highest in A671 standard)

Key difference vs. Class 12: 8.3% higher pressure rating

2. Critical mechanical properties?

Strength:

Yield: ≥35 ksi (240 MPa)

Tensile: 60-85 ksi (415-585 MPa)

Toughness:

Charpy V-notch: Min 20 ft-lb (27 J) at -115°F

Normalization heat treatment mandatory

Ductility: Min 30% elongation

3. Where is it typically specified?

High-pressure LNG transfer systems (export terminals, carrier ship piping)

Arctic gas transmission pipelines with operating temps below -50°F (-45°C)

Cryogenic process plants requiring both low-temp and high-P rating

4. Stringent manufacturing controls?

Welding:

Double-welded seams with 100% RT/UT inspection

No repair welds permitted on final product

Material:

Traceable heats with max 0.025% sulfur/phosphorus

Plate/coil sourced from ASTM A516 Gr.70 equivalent

Testing:

Hydrostatic + supplementary Charpy tests per heat

5. How does it compare to ASTM A333 Gr.6?