Ask an old welder to teach you how to weld feng shui pipes. How can there be no trachoma? Seek details. I basically calculate.

1) First of all, the overhead welding of the lower part of the pipeline is the most difficult to weld, and the molten iron is easy to fall, and the weld is not well blocked, resulting in depression. In order to eliminate and reduce the depression in the overhead welding position, in addition to reasonable selection of groove angle and welding current, the arc breaking action should be decisive, the arc striking action should be accurate and stable, the residence time on both sides of the groove should not be too long, the welding arc should be short, and the molten pool metal should be pushed back by the blowing force of the arc.

2) Welding of overhead welding and downward climbing part: The arc should be held down when the rod is delivered by transverse swing, the rod delivery amplitude is small and the speed is fast, and the inclination angle between covered electrode and the pipe tangent is about 80 ~ 85.

When welding upwards, the covered electrode angle becomes larger and the covered electrode depth becomes shallower. At 7 o'clock, the end of covered electrode is about 1mm from the bottom of the trough, and the covered electrode angle is 100- 105. At this time, about 1/2 arc burns in the tube, the lateral swing amplitude increases, and it stops at both ends of the groove. When vertical welding is achieved, the inclination angle between covered electrode and the pipe tangent is 90.