Trachoma at the weld of spiral seam submerged arc welded steel pipe

The spiral steel pipe is treated like a steel strip in the spin direction of the coiling machine, and then the two sides are welded by the capacitor double-sided submerged arc. Therefore, in the production of spiral steel pipe welding, some quality problems caused by missing welding or wrong edges are prone to occur. The most difficult to solve in this welding is an occurrence of trachoma at the butt weld of the spiral steel pipe.

What is the cause of trachoma? The following is our analysis.

1. During the welding process, the current of the welding gun is too small, and the capacitor time is too short. When the capacitor is not completely welded, it appears to be hardened outside the welding.  So there are sand or bubbles that have not been welded.

2. When the strip steel enters the scimitar-shaped adjustment arc, it is not butted properly, so that the two sides of the strip are not tightly attached, so there is a lot of space between the butted strips.

3. When butt welding the strip steel, the rust or oxide scale on both sides of the steel strip was not cleaned up in time, which caused trachoma after welding.

4. The production equipment was not inspected and sorted out in time after finishing work. The dust on the workbench may be dirty and fall into the welding gap of the butt strip by mistake.

5. The temperature in the operating workshop is too low, or the humidity in the workshop is too humid at that time, which will affect the temperature and dryness of the soldering point.