Does slag in case of overhead weld form a layer inside the molten metal pool?

Question

In the case of horizontal weld, the slag covers the fresh molten melt because it has a lower density and forms a protective layer which prevents molten metal to come in contact with atmospheric gases. But, In Overhead welding as the slag has a lower density, it should move inside the molten metal and form a layer. this layer should cause defects and weakening of the weld. Is this what actually happens?

Answer 1

No, overheads welds can be completed without inclusions and blowholes. Just needs learning and experience.

Check out the various methods of welding as some don't produce much or any slag.