API 2B Q235B STEEL PIPE DN800

Why Can They Withstand High-Pressure Transmission?

Long-distance oil and gas transmission usually requires pipelines to bear high pressure (up to 12MPa or even higher), which puts forward extremely strict requirements on the structural integrity and pressure-bearing capacity of steel pipes. The most prominent advantage of LSAW steel pipes in structural performance lies in their longitudinal weld design. Unlike spiral submerged arc welding (SSAW) steel pipes with spiral welds, the welds of LSAW steel pipes are parallel to the axial direction of the pipeline. This structural design makes the stress distribution of the pipeline more uniform when bearing internal pressure.

The longitudinal weld can directly disperse the axial pressure load, avoiding the stress concentration problem that is easy to occur at the spiral weld of SSAW steel pipes. According to the test data of the International Pipeline Research Association, under the same pressure and pipe diameter conditions, the stress concentration factor of LSAW steel pipes is only 1.1, while that of SSAW steel pipes reaches 1.5-1.8. This means that LSAW steel pipes are less likely to have weld cracking under high pressure. In addition, LSAW steel pipes are made of a single piece of medium and heavy plate through rolling and welding, with fewer welds and higher overall structural integrity. The weld quality is stable under the protection of submerged arc welding, and the weld compactness can reach 99.9%, effectively preventing oil and gas leakage.