Classification of straight seam steel pipe

1. Straight seam high-frequency welded steel pipe: Straight seam high-frequency welded steel pipe is a welded steel pipe that is continuously produced on the production line using steel strip (coil) as the raw material and high-frequency welding process. The material strength is generally below 450MPa, and the materials include J55, L450, X60, Q235, Q345, Q420, and Q460. The diameter range of straight seam welded steel pipe is 14-610mm, and the wall thickness is 1-23.8mm. Straight seam high-frequency welded steel pipe adopts a multi-frame continuous forming process, which has high production efficiency (production speed 15-40m/min). The production line has complete equipment for sizing, straightening, and rounding. And welding is better.

2. Longitudinal submerged arc welded steel pipe: Longitudinal submerged arc welded steel pipe is produced by using a single steel plate as raw material, through JCO or UO forming, submerged arc welding, or a combination of submerged arc welding and other welding processes. The common ones are X70, X80, X120, and so on. The diameter range of straight seam submerged arc welded steel pipe is 406-1422mm, and the wall thickness is 8-44.5mm. In terms of welding edge processing, edge milling is used for processing; in terms of forming, in addition to conventional JCO and UO technologies, some manufacturers adopt progressive forming (PFP) technology and roll bending (RBE) technology; welding, an automatic pre-welding machine with argon or CO2 gas protection and special multi-wire (4 wire and 5 wire) internal and external submerged arc welding equipment, and square wave power supply and power wave power supply device; in terms of diameter expansion, Mechanical diameter expansion is adopted for the entire pipe length; in terms of inspection, on-line flaw detection should be carried out on the plate, automatic ray wave flaw detection hydraulic test should be carried out on the steel pipe after welding, and secondary on-line or off-line ray wave flaw detection should be carried out after diameter expansion.

Sandblasting and de-rusting of straight seam steel pipe are to drive the spraying blade to rotate at high speed through a high-power motor, so that steel shot, steel sand, iron wire segment, minerals, and other abrasives are sprayed on the surface of straight seam steel pipe under the powerful centrifugal force of the motor, which can not only Oxide, rust and dirt, and the straight seam steel pipe can still achieve the required uniform roughness under the action of violent impact and friction of abrasives.

Sandblasting and de-rusting of straight seam steel pipe are to drive the spraying blade to rotate at high speed through a high-power motor, so that steel shot, steel sand, iron wire segment, minerals, and other abrasives are sprayed on the surface of straight seam steel pipe under the powerful centrifugal force of the motor, which can not only Oxide, rust and dirt, and the straight seam steel pipe can still achieve the required uniform roughness under the action of violent impact and friction of abrasives.

After spray de-rusting, not only the physical adsorption on the surface of the pipe can be expanded, but also the mechanical adhesion between the anti-corrosion layer and the surface of the pipe can be enhanced. Therefore, spray rust removal is an ideal rust removal method for pipeline corrosion. Generally speaking, shot blasting is mainly used for the inner surface treatment of pipes, and shot blasting is mainly used for the outer surface treatment of straight seam steel pipes.