1. What is ASTM A671 CC65 Class 32 Pipe?
Definition: An electric-fusion-welded (EFW) carbon steel pipe designed for low-temperature and moderate-pressure service, conforming to ASTM A671 standards.
Grade: CC65 (carbon steel with controlled chemistry, e.g., ≤0.30% carbon).
Class: 32 (indicates higher pressure rating and stricter testing vs. Class 30/31).
2. Key Material & Mechanical Properties
Tensile Strength: ≥65 ksi (448 MPa).
Impact Testing: Mandatory for Class 32 (typically at -50°F/-45°C to ensure low-temperature toughness).
Welding: Longitudinal seams require 100% radiography (RT) or ultrasonic testing (UT).
3. Typical Applications
Oil & Gas: Cryogenic pipelines (LNG, ethylene).
Power Plants: Low-pressure steam lines or cooling systems.
Industrial: Structural components in cold environments.
4. How Does Class 32 Differ from Lower Classes (30/31)?
| Parameter | Class 32 | Class 30/31 |
|---|---|---|
| Design Pressure | Higher (~320 psi) | Lower (~300-310 psi) |
| NDT Requirements | 100% RT/UT mandatory | Optional for Class 30 |
| Impact Test Temp | -50°F (stricter validation) | -20°F to -50°F (varies) |
5. Testing & Certification Requirements
Hydrostatic Test: 1.5x design pressure for ≥10 seconds.
Certification: Mill Test Reports (MTRs) with full traceability (chemistry, mechanical tests).
Optional Tests: Charpy V-notch, hardness tests for specific project needs.
