Weld Bead Appearance
Two characteristics of the weld bead
are the bead height and width, as shown in Figure 7-13. These
characteristics are important to assure
that the weld joint is properly filled, with a minimum of defects,
particularly in multi-pass weldments.
In this case, if the bead height is too great, it becomes very difficult to
make subsequent weld passes that will
have good fusion. The more peaked and narrow the weld bead, the
greater the chance that poor fusion
may occur. The weld bead characteristics may be altered via both size
and shape. In
order to change weld bead size, the lbs. (kg) of weld metal deposited per linear
foot (m) of the weldment must
be changed. Welding current and travel speed are the welding parameters primarily
used to control weld
bead size. For instance, when the current is decreased, the weld bead will become
smaller. The converse
is also true. This relationship can be seen by referring to Figure 7-7.
Weld bead size can also be changed
by varying the arc travel speed. As seen in Figure 7-9, bead size and
travel speed are inversely related.
A decrease in travel speed will result in an increase in the weld bead
height and width. An increase in travel
speed will result in a decrease in the weld bead height and width.
Again, the pounds (kgs) of filler metal
deposited in a linear foot (m) of weld are increased (or decreased).
Both welding current and travel speed
have little effect on weld bead shape. The bead width and height
increase or decrease together.
Continued on next page...
Figure 7-13 Weld Bead Characteristics