In the production process of submerged arc welded steel pipes, especially in high-speed welding, the undercut has become the main defect in the production process of spiral submerged arc welded steel pipes. The defect of undercut mainly has the following surface forms: single-sided undercut, single double-sided undercut, single-sided continuous undercut, and double-sided continuous undercut. The hazards of welds are great, and they become fatal defects of welds just like weld cracks and incomplete penetration. Therefore, we should attach great importance to taking measures for the generation of such defects.
1. Reasons for formation: Generally speaking, the formation of a single side undercut is sporadic and irregular. Excessive changes in the forming seam, small burrs or small gaps on the edge of the strip, and wrong sides of the forming may form a single undercut. For a single side undercut that meets the standard allowable range, the undercut can be eliminated by grinding, and for the undercut that exceeds the standard range, it can be eliminated by repairing.
2. Preventive measures: Due to the uncertainty caused by such defects, we do not need to make major adjustments. We can smooth the edge of the strip as much as possible and keep the forming stable as conditions permit. For the smoothness of the edge of the strip, the edge milling machine can be used instead of the disc shearing edge to solve the problem of forming stability, which can be solved by improving the shape adjustment.
Post time: Jun-14-2023