1. Q: What is the main alloying element that differentiates A335 from A106?
A: ASTM A335 is chrome-molybdenum alloy steel pipe (e.g., P1, P11, P22) for high-temperature service, while A106 is carbon steel. They are not interchangeable.
2. Q: Can you weld API 5L X65 pipe using standard carbon steel procedures?
A: Welding high-grade line pipe like X65 requires qualified procedures due to its higher strength and alloy content. Pre-heat, controlled heat input, and specific filler metals are often necessary to maintain HAZ toughness.
3. Q: What does "HIC Tested" mean for API 5L pipe?
A: Hydrogen-Induced Cracking (HIC) testing is specified for pipe in sour service (containing H2S). Resistant grades (e.g., with controlled chemistry and processing) prevent stepwise cracking.
4. Q: What is the typical grade of black steel pipe used for fencing and handrails?
A: ASTM A500 Grade B or C (round, square, or rectangular structural tubing) or ASTM A53 Grade B are commonly used.
5. Q: What standard covers spiral seam welded pipe?
A: ASTM A139 covers spiral seam welded steel pipe for water or gas transmission, available in Grades A, B, C, D, and E with varying strengths.
