©
COPYRIGHT 1998 THE ESAB GROUP, INC. LESSON
II Contact
Tip - That
part of a gas metal arc welding gun or flux cored arc welding gun that
transfers the welding current to the
welding wire immediately before the wire enters
the arc. Spray
Transfer
- Mode of metal transfer
across the arc where the molten metal droplets are smaller
than the electrode diameter and are axially directed to the weld puddle.
Requires high voltage and amperage
settings and a shielding gas of at least 80%
argon. Globular
Transfer
- Mode of metal transfer
across the arc where a molten ball larger than the electrode
diameter forms at the tip of the electrode. On detachment, it takes
on an irregular shape and tumbles towards
the weld puddle sometimes shorting
between the electrode and work at irregular intervals. Occurs when
using shielding gases other than those
consisting of at least 80% argon and at
medium current settings. Pulse
Transfer
- Mode of metal transfer
somewhat between spray and short circuiting. The specific
power source has built into it two output levels: a steady background
level, and a high output (peak) level.
The later permits the transfer of metal across
the arc. This peak output is controllable between high and low values
up to several hundred cycles per second.
The result of such a peak output produces
a spray arc below the typical transition current. Short-
circuiting Transfer
- Mode of metal transfer
in gas metal arc welding at low voltage and amperage. Transfer
takes place each time the electrode touches or short-circuits to the
weld puddle, extinguishing the arc.
The short-circuiting current causes the electrode
to neck down, melt off, and then repeats the cycle. Trimix
or Triple
Mix - A
shielding gas consisting of approximately 90% helium, 7-1/2% argon, and
2-1/2% carbon dioxide used
primarily for short-circuiting arc welding of
stainless steels. Maintains corrosion
resistance of the stainless steel and produces
good wetting and excellent weld bead shape.
