Tandem mig, Comparing high-deposition tandem mig, High-speed and high-deposition welding – Lincoln Electric Tandem MIG High-Speed and High-Deposition Welding User Manual
Page 8: Reduced heat input and improved bead profiles, Problem - single wire gmaw, Solution - tandem mig
Tandem MIG
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APPLICATION
8/16
High-Speed and High-Deposition Welding
W A V E F O R M C O N T R O L T E C H N O L O G Y
T M
Reduced Heat Input and Improved Bead Profiles
Comparing High-Deposition Tandem MIG
To Single Wire GMAW Process
Problem - Single Wire GMAW
A single wire GMAW process has a useable weld
metal deposition rate based on wire feed speed and
wire diameter. In an attempt to increase weld metal
deposit rates, rather than push a given wire diameter
to unstable wire feed speeds, it is often common
practice to increase the wire diameter and operate
within stable wire feed ranges. The increase in wire
diameter increases the required current draw
associated with a given weld metal deposit rate.
Increased current draw produces higher heat inputs
leading to part distortion and a large fluid weld pool
that is difficult to control.
Solution - Tandem MIG
With the Tandem MIG process the two smaller
diameter electrodes produce a lower heat input and
improved weld pool control when compared to a larger
single electrode process attempting to perform similar
welds. When compared to larger diameter electrode
processes,Tandem MIG typically reduces heat input
by as much as 30-50%. The trail electrode in the
Tandem MIG process is operated in a special Tandem
MIG pulse mode designed to cool the weld pool
created by the lead electrode. The combination of
lower total heat input and the cooling affect of the trail
electrode, allows the trail electrode to be used to help
control weld bead contour. This provides the ability
to better stack horizontal weld beads and produce
flatter horizontal fillets while working at higher
deposition rates.
REDUCED HEAT INPUT EXAMPLE
5/16” Horizontal Fillet Weld
PROCESS
CURRENT
DRAW
(amps)
ARC
VOLTAGE
(DC+)
DEPOSIT
RATE
(lbs./hr)
TRAVEL SPEED
(ipm)
HEAT INPUT
Kj/in
GMAW - 1/16” dia. - ER70S - 6
470
31
17.8
17.7
49.4
FCAW - 3/32” dia. - ER70T - 1
435
29.5
15.8
15.7
49.0
GMAW - 3/32” dia. - ER70C - 6M
500
34
16.2
16.1
63.3
Tandem MIG
Lead .045” dia. ER70S - 6
300
23
23.3
23.1
33.5
Trail .045” dia. ER70S - 6
250
24