X65 large-diameter welded pipe is a high-strength steel grade in the API 5L standard, with a yield strength of not less than 65 ksi (approximately 448 MPa). This high-strength characteristic gives X65 steel grade large-diameter pipes significant advantages when subjected to high pressure and long-distance fluid transportation. At the same time, X65 large-diameter steel pipes also possess good toughness, resistance to hydrogen-induced cracking (HIC), and resistance to sulfide stress corrosion cracking (SSCC), which are crucial for ensuring the safety of oil and gas pipelines.
The performance advantages of X65 large-diameter steel pipe are reflected in three aspects:
Firstly, the strength-toughness balance achieved through microalloying design and controlled rolling and cooling processes results in a yield strength ranging from 448 to 531 MPa, and its Charpy impact energy remains high even at -20℃.
Secondly, the uniform microstructure resulting from the special quenching and tempering heat treatment process (Q&T) ensures that the performance differences between different parts of the pipe are controlled within 5%.
Furthermore, the chemical composition design, with a carbon equivalent (CEIIW) controlled below 0.43% and a Pcm value not exceeding 0.25%, provides excellent weldability for on-site circumferential welding.
Application Scenarios
Subsea Oil Pipelines: In the high-pressure, low-temperature, and corrosive environment of the deep sea, X65 large-diameter welded pipes ensure long-term stable operation due to their high strength and corrosion resistance.
Acidic Oil and Gas Field Gathering and Transportation: Suitable for oil and gas extraction and transportation containing H₂S, such as gathering and transportation networks for acidic oil and gas fields in the Middle East.
Chemical Industry Pipelines: Withstand high temperatures, high pressures, and corrosive media, such as acidic wastewater transportation systems in fertilizer plants.
API 5L X65 Large Diameter Pipe Factory
