API 5L X52 Line Pipe Steel: Oil & Gas Pipeline Grade
API 5L / ISO 3183 · Updated: 2026-05-25
API 5L X52 is a high-strength carbon steel grade for oil and gas transmission pipelines, with 360 MPa minimum yield strength (52 ksi, hence 'X52'). It is supplied as seamless or welded pipe with stringent controls on chemistry, mechanical properties, and non-destructive testing. The controlled rolling or normalizing process produces fine-grain microstructure essential for fracture arrest in high-pressure gas pipelines. X52 welds with cellulosic (E6010/E8010) or low-hydrogen (E7018/E8018) electrodes using qualified API 1104 procedures.
Quick Facts
| Category | Carbon Steel |
| Standard | API 5L / ISO 3183 |
| Density | 7.85 g/cm³ |
| Yield Strength | 360 MPa (52 ksi) |
| Tensile Strength | 460 MPa (67 ksi) |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| L360 | Compare |
| X52 | Compare |
| S355 | Compare |
| L360NB | Compare |
| StE360 | Compare |
Related Materials
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Frequently Asked Questions
What is the difference between X52 and X65 pipe?
X65 has a higher minimum yield strength (450 MPa vs 360 MPa), allowing thinner pipe walls for the same operating pressure—reducing material cost and welding time. However, X65 requires more sophisticated steelmaking (thermo-mechanical controlled processing) and more careful field welding. X52 remains popular for lower-pressure lines, flowlines, and gathering systems where the easier weldability outweighs the weight penalty.