1. For pipelines with high requirements for peak regulation, due to the uneven gas consumption of users and frequent fluctuations in pipeline pressure, the alternating stress on the steel pipe is very large, and the existing defects in the pipe will expand under the alternating stress. If you choose For spiral welded steel pipes with many welds and a high probability of defects, the operation of the pipeline will not be guaranteed.
2. The pipeline crosses the seismic fault zone or passes through the local high-intensity earthquake area. Due to the frequent geological activities in these areas, longitudinal or axial alternating stress will be generated on the pipeline. There are many spiral welds, and the probability of defects is higher than that of submerged arc steel pipes. Under long-term stress, the accident probability of spiral welded steel pipes is much higher than that of submerged arc steel pipes. Therefore, submerged arc steel pipes should be used in this area.
3. Submerged arc steel pipes should be used for pipelines with high requirements for internal and external anti-corrosion layers. Spiral submerged arc welded steel pipes have more weld passes, and the weld reinforcement is generally higher than that of submerged arc steel pipes. When the steel pipes are internally and externally anti-corrosion, the combination of anti-corrosion materials and bare pipes is not as tight as submerged arc steel pipes, and the anti-corrosion effect is not as good as submerged arc steel pipes. The steel pipe is good.
4. For important crossing projects, submerged arc steel pipes should be used. Since future maintenance and management are more difficult than general line sections, it is especially advantageous to use high-performance submerged arc steel pipes.
5. For the weak link of the pipeline, such as the hot-simmered elbow pipe, the submerged arc steel pipe should be used. Due to the change of direction, the hot-simmering elbow bears greater internal and external forces than the straight pipe section of the general line. Due to the influence of various factors during the simmering process, its stress is not easy to eliminate, and it is a relatively weak link in the long-distance pipeline. , the use of submerged arc steel pipes with good comprehensive performance can make up for these deficiencies.