1. Q: What is the key difference between TP304 and TP304L stainless steel pipes?
A: The "L" stands for Low Carbon. TP304L has a max 0.03% carbon (vs. 0.08% in TP304), which minimizes carbide precipitation during welding, improving intergranular corrosion resistance in the heat-affected zone.
2. Q: Where would you use Duplex Stainless Steel pipes like UNS S31803?
A: In highly corrosive environments requiring high strength and resistance to chloride stress corrosion cracking (SCC), such as offshore oil & gas, chemical processing, and seawater systems.
3. Q: What is the primary standard for downhole tubing and casing?
A: API 5CT specifies requirements for seamless and welded steel casing and tubing for use in oil and gas wells, with grades like J55, N80, L80, P110, etc.
4. Q: What is special about API 5CT L80 grade?
A: L80 is a quenched and tempered grade with a yield strength range of 80-95 ksi. Type L80-1 is suitable for sour service (H₂S environments), as it has hardness and material controls per NACE MR0175.
5. Q: What is "Drill Pipe" and its common grade?
A: Drill pipe is a seamless tube used in the drill string to transmit drilling torque and fluid. Common grades are API 5D E75, X95, G105, S135 (increasing strength), often with weld-on tool joints.
