SSAW steel pipe misalignment refers to the parallel deviation of the strip along the thickness direction due to the misalignment of the two edges of the strip at the forming butt joint of the steel pipe. The wrong side will cause the effective wall thickness of the steel pipe to decrease, which will affect the mechanical properties of the steel pipe to a certain extent. Due to the irreparability of the wrong side, the wrong side is one of the main factors causing the degradation of the steel pipe.
Common reasons for the wrong side of the spiral steel pipe(SSAW):
1. When the excess height of the butt welding seam of the head and tail of the steel strip is large, if it is not handled properly during overforming, it is easy to cause a large misalignment.
2. The sickle bend of the steel belt is the most important factor causing the misalignment of the steel pipe. In the forming of the spiral welded pipe, the camber of the steel strip will continuously change the forming angle, resulting in the change of the weld gap, resulting in seam opening, misalignment or even overlapping.
3. The edge of the steel strip is in poor condition.
4. The shape and dimensional accuracy of the head and tail of the non-trimmed steel strip are poor, and it is easy to cause the hard bending of the steel strip to cause misalignment when docking.
In view of the main reasons affecting the misalignment of spiral welded pipes, the following preventive measures are taken.
1. Efforts to reduce strip bending
(1) Improve the ordering standard of raw strip steel in bending to meet the needs of producing qualified products.
(2) Before butt welding and forming, the operator is required to operate carefully, use the control vertical roller correctly, and reduce artificial bending
2. Correct operation of equipment and targeted routine inspections
(1) Regularly check the position of the strip delivery line to prevent the strip from deviating.
(2) Correctly use the strip steel to control the vertical rollers to prevent the plate edge from being thickened.
(3) Always check whether the relevant positions and parameters of the former, guide plate, pre-bending machine and bridge output roller table are appropriate, and adjust in time if any problem is found.
3. Control the position of the welding point of the internal welding. Control the welding of the internal welding at the occlusal point of the steel pipe without the radial displacement of the edge of the plate (that is, without the wrong edge), so as to avoid the wrong edge defect.
4. Set up the adjustment device for the misalignment of the steel pipe
