1. For pipes with high peak shaving requirements, due to uneven gas consumption by users, frequent pipe pressure fluctuations, and alternating stresses suffered by steel pipes, the defects existing in the pipes will expand under the alternating stress. Spiral welded steel pipes with many welds and high probability of defects cannot guarantee their normal operation.
2. The pipeline passes through the seismic fault zone or through the local high-intensity earthquake area. Due to frequent geological activities in these sections, longitudinal or axial alternating stresses can be generated on the pipeline. There are many spiral welds, and the possibility of defects is higher than that of submerged arc welded steel pipes. Under long-term stress, the probability of accidents in spiral welded steel pipes is much higher than that of submerged arc welded steel pipes. Therefore, submerged arc steel pipes should be used in this area.
3. For pipes with high internal and external anti-corrosive coating requirements, submerged arc steel pipes should be used. Spiral submerged arc welded steel pipes have many welds, and the weld seam height is generally higher than that of submerged arc welded steel pipes. When the steel pipe is protected from internal and external corrosion, the combination of anti-corrosive material and bare pipe is not as strong as the submerged arc welded steel pipe, and the anti-corrosive effect will not be submerged.
4. For important cross engineering, submerged arc steel pipes should be used. Since future maintenance and management will be more difficult than ordinary pipeline sections, the use of submerged arc steel pipes with performance is particularly important.
- For weak links in pipelines, such as hot elbow pipes, submerged arc steel pipes should be used. Due to the change in direction, the hot-rolled elbow can withstand greater internal and external forces than the straight pipe section of a normal pipeline. Due to various factors in the restraint 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 welded steel pipes with good comprehensive properties can make up for these shortcomings.
Post time: Apr-09-2020