The production process of straight seam welded steel pipe!

Posted by chase Liu on July 7th, 2023

Straight seam steel pipe is a welded steel tube whose weld seam is parallel to the longitudinal direction of the steel pipe. Straight seam steel pipe is usually mainly ERW pipe and LSAW pipe, and the caliber of ERW pipe is mostly smaller than LSAW pipe. Therefore, large diameter straight seam steel pipe refers to LSAW pipe. In the production process, cold-rolled or hot-rolled steel plates or steel strips are rolled and welded, and then straight seam welded on the welding equipment to form straight seam welded pipes. The welding process of straight seam steel pipe is as follows:

1、Plate detection: ultrasonic inspection shall be carried out first after entering the production line to manufacture steel plates for large-diameter submerged arc welded straight seam steel pipes.

2、Milling: use the edge milling machine to mill the two edges of the steel plate on both sides to achieve the required parallelism, width and groove shape of the plate edge.

3、Pre bending: pre bending the plate edge with the pre bending machine to make the plate edge meet the requirements.

4. Forming: First, on the forming machine, press half of the pre bent steel plate into J shape through multiple step stamping, then press the other half of the steel plate into C shape, and finally form the O shape of the opening.

5. Pre welding: seam weld the formed straight seam welded steel pipe and conduct continuous welding with gas shielded welding.

6. Internal welding: weld on the inner side of the straight seam steel pipe, using longitudinal multi wire submerged arc welding, up to four wires.

The above is about the introduction of straight welded steel pipes. Through the above introduction, I believe you have a deeper understanding of the types and production processes of steel pipes.