API 5L (焊接) — Pipeline Steel Pipe Specifications - Welded Pipe
Grades
Gr.A, Gr.B, X42, X46, X52, X56, X60, X65, X70, X80, X90, X100 (ERW/LSAW/SSAW, PSL1/PSL2)
Chemical composition and mechanical properties
| Grade | Chemical composition | Mechanical properties |
|---|---|---|
| Gr.A | C≤0.14, Mn≤0.90, P≤0.035, S≤0.040 | Rm 310-415 MPa, Rp0.2 ≥165 MPa, A≥27% |
| Gr.B | C≤0.17, Mn≤1.20, P≤0.035, S≤0.040 | Rm 345-450 MPa, Rp0.2 ≥185 MPa, A≥25% |
| X42 | C≤0.26, Mn≤1.40, P≤0.025, S≤0.015, Si (no requirements), Cr≤0.40, Cu≤0.40, Ni≤0.40, Mo≤0.15, V≤0.06, Nb+V≤0.06, Ti≤0.04, B≤0.001, N≤0.012 | Rm ≥415 MPa, Rp0.2 ≥290 MPa, A≥21% (gauge length 50mm), PSL2 has impact requirements. |
Application scope
API 5L (Welding) specifies welded pipeline steel pipes for oil and gas transportation, including resistance welding, straight seam submerged arc welding, and spiral welding (ERW/LSAW/SSAW) methods, delivered according to PSL1 and PSL2. Grades increase in strength from Gr.B to X70 and X80, with PSL2 offering additional impact toughness and stricter composition and weld control, balancing high strength, toughness, and weldability.
Typical applications
Widely used in long-distance oil and gas pipelines, large-diameter oil and gas trunk lines, urban gas pipeline networks, and submarine pipelines, the welding process is conducive to the manufacture of large-diameter, thick-walled pipes. With its high-grade steel plates and controlled welds, PSL2 products are suitable for high-pressure, high-capacity, and long-distance transmission trunk lines, and are the main pipe material for onshore, submarine, and cross-section oil and gas long-distance pipeline projects.
