Production process and process of welded steel pipe

　　Longitudinal welded steel pipe production process is simple, high production efficiency, low cost, rapid development. Generally, the strength of spiral welded steel pipe is higher than that of longitudinal welded pipe. It can be used to produce welded pipe with larger diameter by using narrow blank, and welded steel pipe with different diameter can be produced with blank of same width. However, compared with the straight seam pipe of the same length, the weld length increases by 30 ~ 100%, and the production speed is lower.

　　Large diameter or thick welded steel pipe is usually made of steel billet directly, while thin-walled welded steel pipe with small diameter only needs to be directly welded by steel strip. After simple polishing, wire drawing is used.

　　Process flow of welded steel pipe: raw material uncoiling - leveling - end shearing and welding - looper - forming - Welding - removal of internal and external welding beads - pre correction - induction heat treatment - sizing and straightening - eddy current testing - cutting - hydraulic inspection - Pickling - final inspection - Packaging - delivery.