1. Q: What is the key characteristic of API 5L pipes?
A: API 5L is the American Petroleum Institute specification for line pipe used in the transportation of oil, gas, and water in the petroleum and natural gas industries. It covers both seamless and welded pipes.
2. Q: What is the difference between API 5L PSL1 and PSL2?
A: PSL2 (Product Specification Level 2) has more stringent chemical, mechanical, and nondestructive testing requirements than PSL1, making it suitable for more demanding applications like offshore or sour service.
3. Q: Name a common grade for high-strength, low-alloy (HSLA) seamless pipes.
A: API 5L X70 (or ASTM A694 F70) is a common HSLA grade used for high-pressure transmission pipelines, offering a minimum yield strength of 70,000 psi (483 MPa).
4. Q: What is a "Q&T" pipe?
A: Q&T stands for Quenched and Tempered. It is a heat treatment process that increases the strength and toughness of alloy and carbon steel pipes, commonly used for high-grade line pipes (e.g., X80, X100) and mechanical tubing.
5. Q: What is the purpose of "normalizing" heat treatment on seamless pipes?
A: Normalizing refines the grain structure, improves mechanical properties (toughness), and relieves internal stresses induced during hot working, resulting in a more uniform and predictable material.
