Causes of trachoma at the welding seam of spiral seam submerged arc welded steel pipe

Spiral steel pipe is made of strip steel passing through a coiling machine, bending in a spiral direction, and then double-sided submerged arc welding by capacitors. In the production process of spiral steel pipe welding, many galvanized channel steel situations such as missing welding and misalignment are prone to occur. However, the most difficult to grasp in these cases is the occurrence of trachoma at the butt weld of the spiral steel pipe.

The reasons for the occurrence of trachoma are as follows:
1. During the welding process, the current supplied to the welding torch is too small, and the capacitor time is too short. When the capacitor is not fully welded, the welding surface has hardened, so there are sand grains or air bubbles that have not been fully welded.
2. When the strip enters the arc of the machete shape adjustment, the butt joints are not well connected, the butt joints of the strips are not tightly sealed, and there is an excessively large space between the butt strips.
3. When butt welding the strip, the rust or oxide scale on both sides of the strip is not cleaned in time.
4. The production equipment is not repaired in time. The dust on the workbench may be dirty and fall into the welding gap of the butted strip by mistake.
5. The temperature in the operation workshop is too low or too humid, which affects the temperature and dryness of the solder joints.