Instructions / Assembly

22
www.lincolnelectric.com
GMAW
• Lower hydrogen weld deposit.
• Lower spatter levels when compared to other processes and
m
odes of metal transfer.
• Capable of high deposition welding for heavy plate fabrication.
•
May be used for out-of-position welding.
Modes of Metal Transfer for Tandem GMAW
T
he modes of metal transfer used for the tandem GMAW
variant are axial spray metal transfer or pulsed spray metal
transfer. The combinations of the modes that are popularly
employed include:
•
Spray + Pulse — Axial spray transfer on the lead arc followed
by pulsed spray transfer on the trail arc.
•
Pulse + Pulse — Pulsed spray transfer on both the lead and
the trail arc.
•
Spray + Spray — Axial spray transfer on both the lead and
the trail arc.
The software programs designed to support the
Pulse + Pulse
configuration require that the wire feed speed setting for each
the lead and the trail are the same. Trim values can be adjusted
to account for arc length requirements.
The higher energy
spray + spray configuration is used for
special heavy plate welding where deeper penetration is
required.
Pulse + pulse allows for heavy welding or high speed
sheet metal welding.
FIGURE 15: Tandem GMAW System
Tandem GMAW
PF 10R
Wire Drive
PLC
Motion Control
Dual Torch
(or)
Integrated Torch
Power Wave
455R/655R
PLC
Controller
Filed Bus Interface
Keywords:
H
igh Deposition
Higher Travel Speed
The Tandem GMAW system was developed to take advantage
of the potential for higher travel speeds and higher deposition
rates when using two electrodes in the same molten puddle.
T
he system employs two power sources, two wire drives, and a
system control. It is adapted for either repetitive side-beam type
applications or it is employed with a welding robot. This variant
of the gas metal arc welding process is capable of higher travel
speeds, 1-1/2 to 2 times the speed of a single electrode. Some
travel speeds may exceed 150”/min. (3.81 m/min). Deposition
rates to 42 lbs/hr (19.1 kg/hr) are achievable for heavier plate
welding.
The arc components are broken into two parts: the lead arc and
the trail arc. Generally, two electrodes of the same diameter are
fed into the same puddle. Typical applications include the use of
0.035” – 1/16” (0.9 – 1.6 mm) diameter electrodes. The arcs
are employed in a single barrel torch, and each electrode is fed
through its own conductor tube. Similarly, there are two contact
tips and two diffusers, see page 23.
Features of Tandem GMAW
• Capable of higher travel speeds on sheet metal than
conventional single electrode GMAW.