1. Q: Which grade is used for automotive exhaust systems (non-manifold)?
A: While often aluminized for corrosion resistance, the base steel is typically a low-carbon, formable grade like AISI 1006 or 1008, produced to specifications like ASTM A1011 or similar for strip steel, which is then welded into tube.
2. Q: What does "NACE MR0175/ISO 15156" compliance mean for API 5L pipe?
A: It means the pipe's chemical composition (particularly hardness, sulfur, and phosphorus) is controlled to resist Sulfide Stress Cracking (SSC) in sour service (oil/gas containing H2S). This often requires special processing and lower hardness limits.
3. Q: How does wall thickness schedule (e.g., SCH 40, SCH 80) relate to grade?
A: The schedule defines the wall thickness for a given pipe diameter. The grade defines the material's strength. Both factors together determine the pressure rating of the pipe (e.g., A106 Gr. B, SCH 40 has a specific pressure rating per ASME B31.3).
4. Q: What is the primary use of ASTM A252 pipe?
A: ASTM A252 covers welded and seamless steel pipe piles. Grades 1, 2, and 3 have increasing yield strengths. They are used as structural foundations driven into the ground.
5. Q: What is "DSAW" pipe, and is it common for low-carbon grades?
A: DSAW stands for Double Submerged Arc Welded. It's a process for large-diameter, thick-walled pipe. Common low-carbon grades made via DSAW include API 5L Grade B and X42 through X70 for major pipeline projects. The process creates an internal and external weld seam.
