Comprehensive Properties and Applications of API 5L X46 (L320) Line Pipe Steel

API 5L X46 (L320) is a medium–high strength line pipe steel with a yield strength of 320 MPa. It is suitable for higher-pressure and long-distance transmission systems in the oil and gas industry.

X46 offers strong pressure resistance, weldability, and corrosion resistance. Its high tensile strength allows reduced pipe wall thickness, lowering material cost while maintaining system safety. It also performs well in low-temperature environments.

The steel’s chemical composition is based on low-carbon microalloying with controlled carbon (≤0.26%), manganese, and strengthening elements such as Nb, V, and Ti, which refine grain structure.

X46 is delivered in controlled-rolled, normalized, or TMCP condition, with TMCP offering superior toughness.

Typical applications include high-pressure gas pipelines, long-distance crude oil pipelines, cross-border pipeline systems, subsea pipelines, and offshore structural components.