Single layer welding of butt welding flange

Because the butt welding flange is in an unnatural position, it is difficult to operate stably. At the same time, heavy welding torch and cable should be lifted to increase the difficulty of operation. In addition, the molten iron in the molten pool is easy to sag during overhead welding, which is easy to form convex weld bead and cause molten iron flow in serious cases. Therefore, the welding parameters should be strictly controlled in order to obtain good weld formation.

ANSI standard flanges

Single overhead welding of butt welding flange

Thin butt welding flange often adopts single side welding. In order to weld through, a gap of 1.4 ~ 1.6 mm should be left for butt welding flange.

The welding current is 120-130a, and the arc voltage is 18-19v.

When operating the welding gun, it should be aligned with the groove center, similar to the right welding method.

At this time, the molten pool should be kept by the arc force and surface tension by means of linear or small swing. When the welding speed is too slow, the molten pool metal sags, the weld bead surface appears uneven, and the molten pool metal loses seriously. Therefore, attention should be paid to the state of molten pool, and the welding speed and swing mode should be adjusted in time. When the inclination angle of welding gun is too large, convex weld bead and undercut will be caused.

The next article introduces the multi layer welding of butt welding flange.