1. What is A671 CC65 Class52 steel pipe?
Answer:
A671 CC65 Class52 is an electric-fusion-welded (EFW) carbon steel pipe designed for low-temperature and high-pressure service, conforming to ASTM A671 standards. The "CC65" denotes a minimum yield strength of 65 ksi, while "Class52" specifies the heat treatment condition (typically normalized after welding).
2. Key applications of A671 CC65 Class52 pipes?
Answer:
These pipes are used in:
Cryogenic systems (e.g., LNG storage, refrigeration).
Power plants (low-pressure steam, condensate lines).
Chemical/petrochemical pipelines requiring weldability and toughness.
3. Mechanical properties of A671 CC65 Class52?
Answer:
Yield Strength: ≥65 ksi (448 MPa).
Tensile Strength: 75–95 ksi (517–655 MPa).
Impact Test: Required for low-temperature toughness (e.g., -50°F/-45°C).
Hardness: ≤197 HB (Brinell) to prevent brittleness.
4. How does Class52 differ from Class51 in A671 CC65?
Answer:
Heat Treatment: Class52 is normalized after welding, while Class51 is stress-relieved.
Grain Structure: Normalization (Class52) refines grains for better mechanical properties.
Cost: Class52 may be slightly more expensive due to additional heat treatment.
5. Compliance and certifications for A671 CC65 Class52?
Answer:
Standards: ASTM A671 (EFW pipes), ASME B31.3 (process piping).
Testing: Hydrostatic tests, Charpy V-notch impact tests.
Certification: Mill test reports (MTRs) verifying chemistry, mechanical properties, and heat treatment.
