1. What material is ASTM A333 Grade 3?
Answer: It is a low-temperature carbon steel pipe designed for low-temperature environments (down to -45°C).
Additional information: Its chemical composition (low carbon, silicon, manganese, etc.) and heat treatment (normalizing) ensure low-temperature toughness and prevent brittle cracking.
2. What are its main applications?
Answer:
Liquefied natural gas (LNG) pipelines;
Petrochemical cryogenic equipment;
Refrigeration systems and cold storage piping.
Features: Low-temperature impact resistance, suitable for harsh environments.
3. How does it differ from ordinary carbon steel pipe (such as ASTM A106)?
Answer:
A333 Gr. 3: Emphasizes low-temperature performance and requires passing the Charpy impact test;
A106: Suitable for high-temperature applications (no low-temperature toughness requirement).
Key differences: Heat treatment process and impact test standards.
4. What are its chemical composition and mechanical property requirements?
Chemical composition (%):
C ≤ 0.19, Mn = 0.31-0.64, P ≤ 0.025, S ≤ 0.025.
Mechanical properties:
Tensile strength ≥ 450 MPa, yield strength ≥ 240 MPa, elongation ≥ 30%.
5. How is its low-temperature performance tested?
Answer: The toughness is verified at -45°C using the Charpy V-notch impact test.
Standard requirements: Minimum impact energy per specimen ≥ 18 J, average ≥ 20 J.
