Reasons For Bending Of Large Diameter Spiral Steel Pipes

Reasons why large-diameter spiral steel pipes bend: If large-diameter spiral steel pipes are processed to a certain length, bending will definitely occur. This is a phenomenon and situation that is often encountered in steel pipes. The disadvantages of DN1500 spiral welded pipe production are: because the rolled strip is used as the material, it has a large crescent, and the welding point is at the edge of the elastic strip, so it is not easy to align the welding torch, which affects the welding quality. To do this, complex weld tracking and quality inspection equipment needs to be set up. The welds of spiral submerged arc welded pipes are distributed in a spiral and are long. Especially when welded under dynamic conditions, the welds leave the forming point before they have time to cool down, which can easily cause welding hot cracks. The direction of the crack is parallel to the weld and forms a certain angle with the axis of the steel pipe, generally between 70°. This angle is exactly consistent with the shear failure angle, so its bending, tensile, compressive and torsional properties are far inferior to those of straight seam submerged arc welded pipes. At the same time, due to the limitation of the welding position, the saddle-shaped and fish-ridge-shaped welds are affected. Beautiful.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In addition, during the construction process, the intersecting line welds at the joints of the spiral welded parent pipes split the spiral seams and generated large welding stress, thus greatly weakening the safety performance of the components. Therefore, the non-destructive testing of the spiral welded pipe welds should be strengthened. Ensure the welding quality, otherwise spiral submerged arc welded pipes should not be used in important steel structure situations.