In the long-distance pipeline construction, pipelines account for a large proportion, generally accounting for 35% to 40% of the total pipeline, which is used for the total investment of investment projects. How to choose a reasonable price and excellent pipe performance is particularly important. It is very important to select pipe rationally, save construction investment, and facilitate the construction and safe operation of the pipeline system. High Frequency Resistance Welded Pipe, Spiral Submerged Arc Welded Pipe, LSAW Pipe for Gas Pipeline Straight Seam Pipe.  The diameter range of frequency-limited longitudinal resistance welded steel pipe is generally limited to the domestic steel 406.4mm or less, and the largest diameter 508mm in Japan. For spiral SAW of large diameter tube, LSAW is two kinds. The proportion of spirally welded steel pipe in long-distance pipeline is gradually declining due to many shortcomings in pipe forming process and characteristics. In other countries, especially in many European countries, it has banned the use of spiral submerged arc welded pipes as main pipes. Its unique advantages of LSAW are widely used in long-distance oil pipelines. Its advantages are as follows.
(1) There is no need for unwinding process, and there is less indentation and scratch on the base material.
(2) The cutting edge is staggered, the diameter and circumference are easy to control, and the welding quality is excellent.
(3) Eliminate the residual stress after the expansion of the pipeline is basically stress-free.
(4) Because of the straight line welding and the short weld, the probability of defects is very small.
(5) After expansion, the geometric accuracy of the pipeline is improved, which greatly facilitates the field welding.
(6) Linear welding has little effect on the quality of anticorrosive coating materials.