API 5L (海上焊管) — Welded steel pipes for offshore pipelines
Grades
Gr.B, X42, X46, X52, X56, X60, X65, X70, X80 (LSAW/ERW/SSAW, PSL2)
Chemical composition and mechanical properties
| Grade | Chemical composition | Mechanical properties |
|---|---|---|
| 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. |
| X46 | 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 ≥435 MPa, Rp0.2 ≥317 MPa, A≥20% (gauge length 50mm), PSL2 has impact requirements. |
Application scope
API 5L offshore welded pipe specification for welded pipeline steel pipes used in offshore oil and gas transportation, including LSAW, ERW, SSAW methods and PSL2 delivery grade, with grades including Gr.B and X42 to X80. The standard sets strict requirements on the composition, tensile strength, and impact strength of the base metal and weld, emphasizing good weldability and crack arrest performance, and is suitable for large-diameter subsea and platform oil and gas transportation pipelines.
Typical applications
Widely used in pressure-bearing components such as subsea oil and gas pipelines, large-diameter subsea pipelines, and offshore platform process pipelines. Grades are classified by strength, allowing for selection of different pipe manufacturing processes based on pipe diameter, pressure, and marine environment. With its PSL2 grade stringent base material and weld performance and excellent crack arrest capability, it is suitable for large-diameter offshore oil and gas transportation systems that withstand long-term high pressure, corrosion, and external loads.
