Aluminum 2G Butt Joint - full Penetration

Preliminary welding procedure

Is a full penetration bead on plate  the same as a weld joint?  Well it depends.

If it's a butt joint with no gap at all and a good fit, and the edges have been cleaned properly, then its almost the same as welding a full penetration bead on plate.

So now let's see if the same exact settings that achieve full and uniform penetration welding a simple horizontal bead will translate to a 2G butt joint.

Material type and thickness: 6061 aluminum .050”

Process : TIG/  GTAW

Joint type: square groove weld butt joint full penetration

Filler metal: 5356 1/16” diameter

Tungsten type and size: 2% lanthanated 3/32” diameter ( 1/16" would have worked better for crisper arc starts)

Position: Horizontal 2G

The idea here is to weld beads on the .050” thick 6061 aluminum sheet and to determine exact settings that consistently achieve full penetration.

And to then determine if those same exact settings will work on a 2g butt joint to achieve full consistent penetration.

Cleanliness of the weld area…especially the sheared edge is important and definitely affects how the bead penetrates and especially the surface texture of the penetration side.

Cup size and argon flow rate are also a factor because too much argon flowing can cause an erratic arc and too little argon flow rate will not achieve a clean puddle.

I used the Stronghand tools flow rate checker to make sure my gas flow rate was dialed in.

My first bead was welded with the machine amperage set to 43 amps using the Primeweld TIG325x.  

AC frequency was set to 120hz ( a good all around setting ) with AC balance set to 33% cleaning.

First bead on plate was done without any wire brushing.

Then I wire brushed the last half of the back side and also reduced amperage to 40 amps. 

There was a subtle improvement in appearance on the penetration area that was wire brushed.

So when it came to the actual 2G butt joints, I decided to weld one without wire brushing and the other wire brushed on both sides.

As expected, the best results came from the plate where the edges were cleaned using a deburring tool with both sides wire brushed using a clean stainless steel brush.