TIG steel contamination ?

[FABMAN]

guys,
can you tell me what is going on with this weld ?
i see this problem from time to time when tig welding steel.
this particular job is a hydraulic housing and im trying to weld a new tube/fitting onto it. using .045" ER70S filler. rod is new with no rust on it.
i am only getting this problem in the area where the tube is over the hole which leads into the cylinder. the part and tube is 100% clean.
in another area where i just put a large tack to hold the tube to the housing to secure it when putting a wrench on it, it welded fine without this problem, elimination any filler, argon, or coverage problems, in my mind.
and this condition will pop up from time to time on different parts that never had any fluids through them, so im stumped.
i weld the best i can, use a dremel too to grind out the contaminated pockets, reweld, regrind, reweld... took me an hour to do this, and it should have taken 3 minutes...
oh yea, and when it is popping and making these holes, it contaminates my tungsten, kind of like its attracted to the tungsten..
any input is greatly appreciated.. thanks

[Tweekster]

I work on old car stuff so I run into this all the time, impurities pure and simple.

See the higher levels of black and orange soot around the weld, that's the impurities burning off. Grind and clean more, even the back side, because once the weld puddle penetrates it'll pick up the backside impurities. Once in awhile on nasty stuff I pull out my OA rig and heat the whole area to burn off anything, then clean again.

I welded a stamped bracket and thought I had it very clean, turned out when it was stamped there was a lot of impurities deep in the folds of the stamped curves. It needed a deep grinding and pre-heat before it TIG'd well.

[FABMAN]

thanks man.. that explains it.. impurities right in this area where there was hydraulic fluid....
i finally got it welded, after the regrinds and rewelds, but aint guaranteeing it wont leak.
from the moment i tried to tack it i knew it was gonna be a pain, and should have not messed with it any more.
thanks again man

[Cavi Mike]

That rusting around your weld is a tell-tale sign of air getting into your gas line. Looks like you have a leak between your welder and torch.

[Nick Walkley]

Gas trouble

I agree with cavi mike. You have insufficient gas coverage. Either a breeze blowing your gas away, a leak in you pipe work or the reg is set too low.

Given it it is intermittent I would wonder if it is wind or a leak that only occurs when a certain condition exists ie. Torch angle hose tension etc. of course a fickle breeze or inconsistent torch angle/technique could do it too.

Nick