3.4 Travel Speed
Travel speed is the rate that the gun is moved along the weld joint and is usually measured in mm per minute.
Travel speeds can vary depending on conditions and the welders skill and is limited to the welders ability to
control the weld pool. Push technique allows faster travel speeds than Drag technique. Gas flow must also
correspond with the travel speed, increasing with faster travel speed and decreasing with slower speed.
Travel speed needs to match the amperage and will decrease as the material thickness and amperage
increase.
[1] Too Fast Travel Speed
A too fast travel speed produces too little heat per mm of travel resulting in less penetration and reduced
weld fusion, the weld bead solidifies very quickly trapping gases inside the weld metal causing porosity.
Undercutting of the base metal can also occur and an unfilled groove in the base metal is created when the
travel speed is too fast to allow molten metal to flow into the weld crater created by the arc heat.
[2] Too Slow Travel Speed
A too slow travel speed produces a large weld with lack of penetration and fusion. The energy from the arc
dwells on top of the weld pool rather than penetrating the base metal. This produces a wider weld bead with
more deposited weld metal per mm than is required resulting in a weld deposit of poor quality.
[3] Correct Travel Speed
The correct travel speed keeps the arc at the leading edge of the weld pool allowing the base metal to melt
sufficiently to create good penetration, fusion and wetting out of the weld pool producing a weld deposit of
good quality.
To Next Page
Loading...
