Tweco 500SP PowerMaster Automation - Manual (Page 62)

POWERMASTER 400SP, 500SP AUTOMATION
6-2 March 16, 2007
Art # A-06381
Long Arc Short Arc
B. Length of the wire electrode
The distance between the torch and the workpiece
should be 10 – 12 times the diameter of the wire.
Altering the distance of the torch will influence the
electrode stick out.
A longer electrode stick out reduces the amperage
and the penetration.
A shorter electrode stick out increases the amperage
if the wire-feed speed remains the same.
Art # A-06382
Long electrode stick out Short electrode stick out
6.02 Holding and Manipulating the
Torch
NOTE
Metal shielded gas welding can be welded
in all positions: horizontal, vertical-down,
vertical-up, overhead and in horizontal-
vertical position.
When horizontal welding, hold the torch vertical to
the workpiece (neutral torch position) or up to 30°
“pushing” the torch. For best depth of penetration
and shielding gas coverage hold the torch in the
neutral position. Please note that if the torch is tilted
too far, it is possible that air will be sucked into the
shielded gas and may result in porosity. For vertical
or overhead welding a slight pushing motion is
required. Vertical down welding is most used for thin
materials, hold the torch at the neutral or slightly
“dragging” position. Some experience is required as
the welding pool could run ahead of the arc and cause
weld defects. There is a danger of lacks of fusion with
thicker material due to the welding pool being very
liquid from high voltage.
Art # A-06380 Welding direction
pushing the weld
Welding direction
dragging the weld
Avoid extreme side to side movements as it can cause
the weld pool to dam up in front of the arc. This can
cause lacks of fusion due to the welding pool flowing
ahead of the welding arc. The side to side motion
should only be used as wide as is necessary to reach
both sides of the joint. If the joint is too wide you
should weld two parallel weld beads. When vertical-
up welding, the side to side motion should follow the
shape of an open triangle.
A. Length of the arc
Welding with a longer arc reduces the penetration,
the welding bead is wide and flat with increased
spattering. The welding material is transferred with
slightly larger drops than welding with a shorter arc.
A longer arc is useful for welding a fillet weld to form
a flat or concave seam. Welding with a shorter arc (at
the same amperage) increases the penetration, the
welding bead is narrow and high with reduced
spattering. The welding material is transferred with
smaller droplets.