22
3.4 GOUGING OPERATION (continued)
The angle at which the torch is held depends on the
current setting and the torch travel speed. At 35 amps,
(Range I), the recommended lead angle is 35°. At 105
amps (Range III), the recommended lead angle increases to
45°. An angle greater than 45° may result in inconsistent
metal removal. If the lead angle is too small (less than
35°), less material may be removed, requiring more passes.
In some applications, such as removing welds or working
with light metal, this may be desirable.
The tip to work distance affects gouge quality and depth.
A standoff of 1/8 - 1/4 in (3 - 6 mm) allows smooth,
consistent material removal. A smaller standoff may
result in a severance cut rather than a gouge. A standoff
greater than 1/4 in (6 mm) may result in minimal metal
removal or loss of transferred main arc.
Slag generated by gouging on materials such as carbon
and stainless steels, nickels, and alloyed steels, can be
removed easily in most cases. There is little, if any, slag
produced when gouging aluminum, as the material is
vaporized. Slag does not obstruct the gouging process if it
accumulates to the side of the gouge path. However, slag
build-up can cause inconsistencies and irregular metal
removal if large amounts of material build up in front of
the arc. The build-up is most often a result of improper
travel speed, lead angle, or standoff height.
Standoff Distance
Lead Angle
Slag Build-up
OPERATION
Plasma Gas Ar/H2 Ar/H2 Nitrogen Nitrogen Air
Secondary Gas Nitrogen Air Air CO2 Air
Carbon Steel Good Good Good Good Excellent
Stainless Steel Excellent Good Good Good Fair
Aluminum Excellent Good Fair Good Fair
Table 3-A Recommended Gases for Plasma Arc Gouging
To Next Page
Loading...
Need help?
General
