1. Q: What is "GROOVE" in the context of pipes like ASTM A53?
A: It refers to mechanical grooving (e.g., a cut groove) on the pipe exterior to accept a grooved coupling (e.g., Victaulic-style) for fast assembly.
2. Q: Why is post-weld heat treatment (PWHT) sometimes required for carbon steel pipe welds?
A: To relieve residual stresses, especially in thick-walled sections or for services susceptible to stress corrosion cracking (SCC).
3. Q: What is the key material property difference between API 5L Gr. B and X42?
A: Minimum Yield Strength. Gr. B is 35 ksi (241 MPa), X42 is 42 ksi (290 MPa). X42 is a higher strength grade within the API 5L specification.
4. Q: What is "HIC Test" and when is it specified?
A: Hydrogen Induced Cracking Test. It's specified for pipes in "sour service" (wet H2S environments) to ensure resistance to stepwise cracking.
5. Q: What does "SAW" pipe mean and for what sizes is it common?
A: Submerged Arc Welded. Common for large diameter pipes (e.g., over 24" NPS) used in transmission pipelines. It can be longitudinally (LSAW) or spirally (SSAW) welded.
