Select of Straight Seam Submerged Arc Welded Steel Pipe

　　(1) For high peak load requirements of the pipeline, because the user's gas consumption is very uneven, pipeline pressure fluctuations in the frequent, alternating stress steel to withstand large tubing will expand the existing defects in alternating stress, if more choice weld defects high probability of spiral welded steel pipe, the safe operation of the pipeline will not be guaranteed.

　　(2) Pipeline crossing earthquake fault or by topical highly seismic region, due to the geological activity of these lots frequent pipeline will have a vertical or axial alternating stresses. Spiral weld much higher than the probability of defect LSAW steel pipe, under long-term stress, spiral welded steel pipe is much higher than the probability of an accident LSAW steel pipe, therefore, in such areas should be used straight submerged arc welded pipe.

　　(3) Internal and external coating requires a high piping should be used LSAW. Spiral submerged arc welded pipe weld more general than the weld reinforcement LSAW high, when the steel pipe internal and external corrosion, anti-corrosion materials and combination of the bare tube is not as close LSAW, anticorrosive effect is not good LSAW steel pipe.

　　(4) For important wear across the engineering, use LSAW. Due to difficulties in future maintenance and management than the general line segment, therefore, the use of excellent performance LSAW particularly necessary.

　　(5) For the pipeline weaknesses, such as heat and simmer elbow pipe should be used LSAW. Heat simmer elbow since the direction of change, their exposure to internal and external forces than the general line of straight pipe should be large, due to the impact of various factors in the simmering process, it is not easy to eliminate stress, is a long-distance pipeline in the weak link , integrated performance good LSAW can make up for these deficiencies.