Large -caliber steel pipes are made of thick plates and hot -rolled plates. The manufacturing method is first classified according to the welding method, and the high -efficiency and high reliability SubmerGed Arc Welding steel pipe is called the SAW steel pipe. The large -caliber steel pipe discussed in this article is mainly targeted at this SAW steel pipe. SAW steel pipes are divided into buried arc-welded stitched steel pipe L-SAW and spiral welding buried arc welding spiral steel pipe H-SAW. The L-SAW steel pipe has a UO molding method suitable for large-scale production, a curved roller method and pressure machine tool method suitable for a large number of varieties.
The JCOE molding method is a method between the UO molding method and the pressure machine tool method. Whether there is a diameter process at the end of the pressure has a great impact on the performance of the steel pipe, and whether the process is also one of the classification methods. The H-Saw is equivalent to the spiral welded pipe, forming the rolled steel plate into a spiral shape, and then welded the docking part. In addition to the traditional methods of forming and positioning welding, in order to obtain high productivity and high -quality steel pipes, the two -step spiral welding method of SAW can also be used after positioning welding.
Under normal circumstances, materials used to process large -diameter spiral steel pipes are divided into many levels. Each level is different, and there are usually great differences in quality. Therefore, to determine the quality of quality, the manufacturer must show the corresponding material certificate, so as to know the level of the level. In this comparison, we can see that the quality is different.
When processing large -diameter spiral steel pipes, surface treatment is an essential process. In order to ensure the strict quality of the steel pipe, the surface treatment needs to be more strict when leaving the factory to ensure the appearance quality and corrosion resistance. Large, customers' choices will still be different.
