DECREASE wire diameter to increase penetration!?!?

[clevinski]

Wait a minute! This can't be right! DECREASE wire diameter to INCREASE penetration???

Since increasing stickout decreases penetration (more resistance = less current), increasing wire diameter should similarly increase current and increase penetration, right? Am I missing something, or is this just a mistake?

The chart below is from http://www.esabna.com/EUWeb/MIG_handbook/592mig7_15.htm.

 

[malcolm]

Might well be what us writers call a mistake. Every tutorial should have at least two mistakes and they are deliberately included to keep you sharp.

You would use a thinner wire to help avoid blowing holes (excessive penetration) in thin sheet, so I'm with you on that.

 

[zst]

I interperate that chart in following way:
- IF YOU KEEP THE SAME CURRENT and the same thickness of base material, then the penetration would be deeper using wire with smaller diameter than one using the wire with bigger diameter.

You could try to use 0.8 mm wire at 100 A and 1.0 mm at 100 A. I could assume that the penetration would be deeper with 0.8 mm.

This is interesting question and if someone KNOWS what is true, it would be fine to hear it.

 

[matt1978]

I think it maybe correct, but only in certain instances,

For example, if you consider 100 amps as Zst said,

100 Amps on 0.8mm wire would be in Spray arc mode but only in Dip Transfer in 1.2mm wire, so if you was welding a T-Fillet for example, you would expect more pentration with the 0.8mm in Spray wouldn't you.

The thing to work with on Mig/Mag welding is Wire feed speed rates, not amps or voltage.

Amps and Voltage can change with stick out values and gas mixes, but wire feed rate is always constant.

 

[shenion]

I find the table useless. you change the voltage and you need to change the wire speed. The table acts like any single parameter needs to be changed but they are related.

 

[clevinski]

I think the idea is that, if you change only one variable, what effect will it have on the welding? But as Shenion says, many of the variables are related and you can't change only one practically. Realistically, I would say that if I want more penetration I'm going to go to a heavier wire, but that will also increase current (assuming the voltage is essentially constant). I think Zst may be right about what was intended, but if so, the information is pretty much useless, unless your welder allows you to fix both voltage and current while you change wire speed.