20
no pulse
high frequency
pulsing
no pulse
high frequency
pulsing
DC Pulse TIG Welding
Pulse TIG welding is when the current output (amperage) changes between high and low current.
Electronics within the welding machine create the pulse cycle. Welding is done during the high-amperage
interval (this high amperage is referred to as peak current). During the low amperage period, the arc is
maintained but the current output of the arc is reduced (this low amperage is referred to as base current).
During pulse welding the weld pool cools during the low amperage period. This allows a lower overall heat
input into the base metal. It allows for controlled heating and cooling periods during welding providing better
control of heat input, weld penetration, operator control and weld appearance.
There are 4 variables within the pulse cycle:
Peak Current - Base Current - Pulse Frequency - Pulse Width
Setting and manipulation of these variables will determine the nature of the weld current output and is at the
discretion of the operator.
Peak Current is the main welding current (amps) set to melt the material being welded and works much
the same as setting maximum amperage values for regular DC TIG: as a guide use 30-40 amps for every
0.040”of material thickness.
Base Current is the set level of background current (amps) which cools the weld puddle and affects overall
heat input. Background Amps is a percentage of peak amperage. As a rule, use enough background
current to reduce the weld pool to about half its normal size while still keeping the weld pool fluid. As a
guide start by setting the background amperage at 20 to 30 percent of peak amperage.
Pulse Frequency is the control of the amount of times per second (Hz) that the welding current switches
from Peak Current to Base Current. DC Pulse TIG frequency generally ranges from 20 to 300 HZ depend-
ing on the job application. Control of the pulse frequency also determines the appearance of the weld.
Pulse Width is the control of the percentage of time during one pulsing cycle the power source spends at
the peak current (main amperage). Example is with the Pulse Width set at 80 percent and a rate of 1 pulse
per second (PPS), the machine will spend 80% of the pulse at peak amperage and 20% at the base cur-
rent. Increasing the pulse width percentage adds more heat to the job, while decreasing pulse width per-
centage reduces heat
peak
background
ON
OFF
Current
Time
DC Pulse Tig welding allows faster welding speeds with better control of the heat input to the job, reducing
the heat input minimising distortion and warping of the work and is of particular advantage in the welding
of thin stainless steel and carbon steel applications. The high pulse frequency capability of the advanced
inverter agitates the weld puddle and allows you to move quickly without transferring too much heat to the
surrounding metal. Pulsing also constricts and focuses the arc thus increasing arc stability, penetration and
travel speeds.
Summary of Contents for KUMJRRW160
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