Q: What does "sour service" mean in pipeline standards like CSA Z245.1, and how does it affect grade selection?
* A: "Sour service" refers to environments containing wet H₂S, which can cause sulfide stress cracking (SSC). Standards restrict the maximum hardness and strength grades (e.g., up to Grade 483 in CSA Z245.1) and may require enhanced toughness testing (Category II/III)-6.
Q: In the oil and gas pipeline standard CSA Z245.1, what does "Category II" pipe requirement mean?
A: Category II pipe requires proven notch toughness properties verified through tests measuring both energy absorption (e.g., Charpy impact) and shear fracture area appearance to prevent brittle fracture-6.
Q: What grades are covered in API 5CT for casing and tubing?
A: API 5CT includes multiple groups: carbon steel grades like H40, J55, K55; high-strength grades like N80, L80, C90, T95; and corrosion-resistant alloys (CRAs)-4.
Q: What is GB 9948-1988 used for, and what are typical grades?
A: It covers seamless pipes for petroleum refining (e.g., for boilers, heat exchangers). Grades include 20#, 12CrMo, 1Cr5Mo, and 1Cr19Ni11Nb (stainless)-8.
15. Q: For corrosive fluid transport, what is a key Chinese standard for stainless steel seamless pipes?
* A: GB/T 14976-2012 is the standard for "Stainless steel seamless tubes for fluid transport"-3.
