[DL Brennan]

Hi all, I'm new to the forum here.

Question:

I realize that increasing WFS will increase amperage in short circuit mig (given the voltage stays constant), so one would naturally think that that also increases weld penetration/fusion. But I've also heard that since turning WFS down will allow you to run slower, you will actually be putting more heat into the weldment, hence increasing penetration and/or fusion. Conversely, running at a higher WFS will only force you to move faster and thereby "colder".

Can someone clarify this for me?

[MinnesotaDave]

Mig is really easy to make a weld that doesn't penetrate.

For definition of penetration we'll use depth of fusion.

Stay with amps (wire feed speed) as your factor in penetration.

Just because a person goes slower and puts more overall heat into a piece does not necessarily translate into penetration.

You need enough amps to penetrate, enough volts to get proper bead profile and the proper technique of staying in front of the puddle to cut into metal.

If your arc is back in the puddle instead of the leading edge, penetration (depth of fusion) will be reduced.

[Oscar]

But I've also heard that since turning WFS down will allow you to run slower, you will actually be putting more heat into the weldment,

I believe the mistake in that statement is that instead of "weldment" it would be "workpiece", which is not the same thing. If turning down the wirespeed to make you go slower to in turn put more heat into the weldment were true, then no one would ever need anything more than a whimpy 110V welder to weld 1"+ thick steel. We would just turn it down to go super slow, and everything would be fine and dandy. Obviously that is not the case in the real world. There may be some truth to the statement that you heard, but there are always limitations and the only way to know those limitations is to cut and etch to see what is really going on.

[DL Brennan]

Great points...thank you both!