14
Arc voltage is used to control the shape
of the weld bead. As can be seen in
Figure 7-8, as the arc voltage (arc
length) increases, the bead height decreases and bead width increases. Here the
overall size of the weld
bead remains constant. Only the shape or contour of the bead is changed. By increasing
the bead width,
the bead height becomes flatter and the weld metal is said to ”wet”
the base materials more efficiently.
Fusion to the base plate is improved. Wire
extension and the welding technique employed (backhand or forehand welding) also
affects these characteristics,
but only to a limited extent. When long extensions are used to increase deposition
rates, bead height
will increase to a greater extent than bead width. Although larger, the weld bead
becomes more peaked
as shown in Figure 7-14. A backhand welding technique will also produce a high,
narrow weld bead. Decreasing
the lagging torch angle will decrease the bead height and increase the width.
The forehand technique
yields the flattest, widest weld bead. This
section has discussed the various effects of several welding parameters and techniques.
As a summary,
Table 7-2 outlines these parameters and the changes necessary
to alter a variety of weld characteristics.
Figure 7-14 – Effect of Electrode
Extensions on Weld Bead
Characteristics
