1. What is ASTM A671 CC60 Class 11?
Definition: Electric-fusion-welded (EFW) pipe for low-to-moderate temperature and pressure service, optimized for cryogenic and industrial applications.
Key Specs:
Yield Strength: 60 ksi (414 MPa) at -20°F (-29°C).
Pressure Rating: 1,500 psi (103 bar) (Class 11).
Material: Carbon steel with impact-tested properties (typically killed steel).
2. Applications
Industrial:
Cryogenic storage tanks and transfer lines (LNG, liquid oxygen).
Refinery and chemical plant piping (non-corrosive fluids).
Energy:
Low-pressure gas transmission.
Utility steam lines (low-temperature sections).
3. Material Properties & Testing
| Property | Requirement | Test Standard |
|---|---|---|
| Yield Strength | ≥60 ksi at -20°F (-29°C) | ASTM A370 |
| Charpy Impact | ≥20 ft-lb (27 J) at -50°F (-45°C) | ASTM A673 (Group 2 or higher) |
| Hydrostatic Test | 1.5x design pressure (2,250 psi) | ASTM A671 Section 12 |
| NDT | Radiographic or ultrasonic testing | ASTM E94/E213 |
4. Manufacturing & Certification
Process:
Submerged arc welding (SAW) or similar EFW methods.
Optional post-weld heat treatment (PWHT) for stress relief.
Certification:
Complies with ASME B31.3, API 5L PSL1, and ISO 3183.
Optional NACE MR0175 for sour service.
5. Operational Limits & Compliance
Temperature Range: -50°F to 650°F (-45°C to 343°C).
Pressure Limit: ≤1,500 psi (103 bar) for Class 11.
Key Standards:
ISO 3183 (Pipeline transportation systems).
ASME B31.3 (Process piping).
