Abstract: Since the development of offshore oil and gas, the increased submarine oil and gas pipelines were installed. All the early steel pipes of submarine pipeline were depended on importing because of the strict requirements of comprehensive properties such as anti-corrosion, resistance to pressure and so on. In order to research and develop domestic steel pipe used for submarine pipeline, the Longitudinal-seam Submerged Arc Welded (LSAW) pipes were made of steel plates cut from the levelled steel rolls by both JCOE and UOE forming process. And the mechanical properties of the pipe base metal and weld metal were tested, the results were in accord with the corresponding pipe specification API SPEC 5L or DNV-OS-F101, which showed the domestic LSAW pipes could be used to the submarine oil and gas pipeline.

Key words: Mechanical Properties, Offshore oil and gas, Longitudinal-seam Submerged Arc Welded Pipe (LSAW), Pipeli