7
Weld No. 2, made with the He-Ar-Co2
mixture is also convex. Spatter on the plate is considerable. When
inductance is introduced midway through
the sample, the reduction in spatter is dramatic; the bead
becomes flat and the cross-section on
the bottom right shows penetration of the weld bead into the
workpiece has increased.
In spray arc welding, the addition of
some inductance to the power source will produce a better arc start. Too
much inductance will result in erratic
starting. When
conditions of both correct shorting current and correct rate of current rise exist,
spatter is minimal. The
power source adjustments required for minimum spatter conditions vary with the
electrode material and size.
As a general rule, both the amount of short circuit current and the amount of
inductance needed for ideal
operation are increased as the electrode diameter is increased.
Figure 3-6 - Effect of Inductance on
Weld Appearance
