20 d.
Width and Depth of Welding Flux The
width and depth of the layer of granular welding flux influence the appearance
and soundness of the finished weld as well
as the welding action itself. If the granular
layer is too deep, a rough, ropy weld is likely to result. The gases generated
during welding cannot readily escape, and
the surface of the molten weld metal is irregularly distorted. If
the granular layer is too shallow, the welding zone will not be entirely submerged.
Flashing and spattering will be present;
the weld will have a bad appearance, and may be porous. An
optimum depth of granular material exists for any set of welding conditions. This
depth can be established by slowly increasing
the granular material until the welding action is submerged and flashing no
longer occurs. The gases will then puff up quietly around
the welding wire, sometimes burning. It
is seldom that too narrow a layer is applied. The safest procedure is to apply
a layer that is three times the width of
the fused portion. In large welds, a greater allowance may be necessary. A layer
that is limited by too narrow confines
interferes with the normal lateral flow of weld metal resulting in reinforcement
that is narrow, steep-sided, and poorly
“faired in” the baseplate or the edges. e.
Mechanical Adjustments The position
of the welding wire must be maintained to control the shape of the weld and the
depth of penetration. The wire may be guided
mechanically or manually adjusted as the weld progresses. While
the welding is going on, inspection will indicate whether the backing is tight
against the underside of the joint. If
it is not, too much metal may flow into the space, resulting in reduced weld reinforcement,
undercutting, and a ruined weld.
