In the production of straight seam steel pipes, the wrong side occurs from time to time, and there are many factors affecting it. In production practice, steel pipes are often degraded due to dry misalignment and excessive tolerance. Therefore, it is necessary to analyze the causes of wrong edges of straight seam steel pipes and preventive measures. 　　

1. The sickle bend of the steel belt is the most important factor causing the wrong edge of the steel pipe. In the forming of spiral welded pipes, the sickle bend of the steel strip will continuously change the forming angle, resulting in the change of the weld gap, resulting in open seams, staggered edges or even overlapping edges. The quality of the steel pipe is seriously affected. Therefore, observe the sickle bend after uncoiling the steel strip. By controlling the vertical roll, the disc shear can cut off part of the sickle bend and the continuous control and correction of the forming angle are to reduce the sickle bend of the steel strip during the production process. An effective way to produce wrong sides. 　　

2. Due to the poor shape and dimensional accuracy of the head and tail of the untrimmed steel strip, it is easy to cause hard bending of the steel strip during butt joints and cause wrong edges. 　　

3. When the reinforcement of the welding seam of the head and tail of the steel strip is large, if the over-forming is not handled properly, it is easy to cause a large wrong edge. 　

4. The poor condition of the edge of the steel strip is another important reason for the wrong edge.