Straight line on the root - aluminum MIG/TIG welding

[guest3000]

Hello,

do you know, why does such a straight line form in the weld root as in the attached video? Example from 6:20
Link:

It looks as if the oxide coating has formed a thin layer in the weld root but we have a full penetration.

 

[Munkul]

Probably a freeze line. You get it with high amps MIG as well on steel. Its not a problem per se, on steel it kinda shows that you're GOOD and hot, but bears watching because it hints that you're almost too hot and fast per pass.

 

[chrismac]

I have seen this in the past, never heard of a freeze line, I have learned something tonight, I always thought it was something to do with how the plate butt weld in aluminium was melting together but not cleanly enough have a root like we would expect on mild or stainless steel, its exactly where the joint line is.

I had nothing to base my thoughts on just guessing.

 

[chrismac]

It's the oxide. You don't get any cleaning of the arc on the backside of the weld

You have the great ability to find the words I cannot, thanks for the explanation.

 

[Shedendman]

Good thing about Jodys vids are theres no stupid rock music playing in the background plus,hes been there seen it done it

 

[guest3000]

It's the oxide. You don't get any cleaning of the arc on the backside of the weld

I agree with you. In the video, you can see that the phenomenon does not occur in the area which was tack-welded before and cleaned after welding.

What do you think about RT? Is it possible to see this line on radiogram? My RT team, after observing the photos, pointed this out as a nonconformity - a lack of penetration.

 

[chip]

I'm not a tig welder but watch some of the guys on weldtube tig welding pipe I'm sure one or two describe it as a wet line. edited to say they were oil and gas guys
see this at 7.18 minutes in ..warning music...but they know there stuff.