Bead Welding (fig14 on the Following Page.).

Welding Operations, I
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arc, will be difficult to control and a considerable portion of

this metal will be lost as spatter. The long arc will melt the

electrode quickly, and the metal is not always deposited at the

point desired.

In general, the long arc results in poor weld

penetration, excessive overlap, and burned and porous metal in

the weld as shown in figure 13, views B through D, on the

previous page.

(3) Short Arc.

(a) The short arc (figure 13, view E) is the correct and

desired procedure for welding.

With the short arc, the molten

metal leaving the end of the electrode passes from the atmosphere

by way of an enveloping arc flame. The short arc permits better

control of the weld metal deposited resulting in a welded bead of

better quality.

Generally, a short arc provides maximum

penetration and better physical properties in the weld and

deposits the maximum amount of metal at the point of welding.

Porosity, overlap, and weld metal spatter are kept to a minimum.

(b) A very short arc, however, is undesirable. It will produce

much spatter, will go out frequently, and make continuous welding

difficult; the results being similar to those shown in figure 13,

view B.

Bead Welding (figure 14 on the following page).

(1) When the arc is struck, metal particles melt off the end of

the electrode and are deposited in the molten puddle on the

surface of the work. As the electrode melts it becomes shorter

and causes the arc to increase in length unless the electrode is

fed down to the work as fast as the end is melted off and

deposited.

Before moving the electrode forward, the arc should

be held at the starting point for a short time to ensure good

fusion and to allow the bead to build up slightly.

When the

welding machine is adjusted for proper current and polarity, good

bead welds can be made by maintaining a short arc and welding in

a straight line at a constant speed.