5 Depth
of Flux The depth
of the layer of submerged arc welding flux applied should be no greater than is
required to obtain quiet
welding action and an absence of porosity in the finished weld.
Figure 30 shows the effect of the proper
depth and too shallow a depth. If
too deep a layer is used, the weld will be rough and uneven. Porosity may also
occur as gases generated during
welding cannot escape through the thick layer of composition.
The unfused flux can be removed a short
distance behind the welding zone where the fused material has
solidified. However, under
certain conditions it may be desirable
not to disturb the material until the heat has become better distributed
throughout the section.
The fused submerged arc flux should
not be forcibly loosened while the weld metal is at a high temperature.
If allowed to cool, the fused submerged
arc flux will become detached so it can be brushed away with little
effort. Sometimes a small section is
removed forcibly for a quick inspection of the weld surface.
It is important that no foreign material
be picked up with the reclaimed flux. To prevent this, a space about a
foot wide should be cleaned on either
side of the welding zone before the flux is laid down. If the recovered
flux contains fused pieces, it should
be passed through a screen with openings no larger than 1/8-in.
The submerged arc welding flux is thoroughly
dry when shipped from the plant. If it becomes damp or wet, it
must be dried before being used since
moisture is a cause of porosity.
