Production and process flow of welded steel pipe

　　Longitudinal welded steel pipe has the advantages of simple production process, high production efficiency, low cost and rapid development. The strength of spiral welded steel pipe is generally higher than that of straight welded steel pipe. It can produce welded pipe with bigger diameter with narrower blank, and DN200 Q235B ERW Black Welded Steel Pipe with different diameter can also be produced with blank of the same width. However, compared with the straight seam pipe of the same length, the length of the weld increases by 30-100%, and the production speed is lower.

　　Longitudinal welded steel pipe has the advantages of simple production process, high production efficiency, low cost and rapid development. The strength of spiral welded steel pipe is generally higher than that of straight welded pipe. It can produce welded steel pipe with bigger diameter with narrower blank, and welded steel pipe with different diameter can also be produced with blank of the same width. However, compared with the straight seam pipe of the same length, the length of the weld increases by 30-100%, and the production speed is lower.

　　Welded steel pipes with large diameter or thicker thickness are usually made directly from billet, while thin-walled welded steel pipes with small welded steel pipes only need to be welded directly through steel strips. Then after a simple polishing, the wire drawing can be done.

　　Raw materials uncoiling-leveling-end shearing and welding-looper-forming-welding-internal and external bead removal-pre-correction-induction heat treatment-sizing and straightening-eddy current testing-cutting-hydraulic inspection-pickling-final inspection (strict checking) -packaging-shipment.