Leaking welds on small tubes... precision tig welding help needed
Leaking welds on small tubes... precision tig welding help needed
(OP)
Hey guys,
We are welding some small 316 SS tubes into some 1018 carbon steel with 309L Tig wire... there are 4 pictures attached to show the welds... the welds have to hold pressure and most are leaking. It appears most are leaking on the area between the tubes as the welder is having a hard time welding inside that area... also some of the welds are cracking. Anyone have any advice? See pictures... Thanks for any help!
We are welding some small 316 SS tubes into some 1018 carbon steel with 309L Tig wire... there are 4 pictures attached to show the welds... the welds have to hold pressure and most are leaking. It appears most are leaking on the area between the tubes as the welder is having a hard time welding inside that area... also some of the welds are cracking. Anyone have any advice? See pictures... Thanks for any help!





RE: Leaking welds on small tubes... precision tig welding help needed
RE: Leaking welds on small tubes... precision tig welding help needed
RE: Leaking welds on small tubes... precision tig welding help needed
RE: Leaking welds on small tubes... precision tig welding help needed
StrykerTECH Engineering Staff
Milwaukee, WI
http://www.stryker-tech.com/
RE: Leaking welds on small tubes... precision tig welding help needed
He is just tig welding around the outsides of the tubes and then trying to get in between them...
RE: Leaking welds on small tubes... precision tig welding help needed
RE: Leaking welds on small tubes... precision tig welding help needed
Other alternative is to get the *best* Tube-Welder from the Boilermakers.
RE: Leaking welds on small tubes... precision tig welding help needed
Are you purging the s/s tubes ?
The reason I ask about the purge is you may be able to perform a very small autogenous weld first to "seal" the joint and then any additional weld put in with filler metal is purely reinforcement.
Similar procedure to socket welding with SMAW. Put a small, hot E6010 to "seal" the joint, grind and then one run with an E7018.
Weld similar to how the boiler tube welders do to get into the tight areas - extend the tungsten and weld as far as you possibly can from one side and then hit the slope down button (this negates trying to tail off when the ceramic is jammed between two tubes)Repeat the procedure from the other side and hopefully the two halves will overlap and you will have a nicely sealed joint.
Are the tubes sitting flush with the end of the 1018 or are they recessed into a hole in the 1018 ?
Hope that helps,
Regards,
Kiwi
RE: Leaking welds on small tubes... precision tig welding help needed
B.E.
RE: Leaking welds on small tubes... precision tig welding help needed
See attached pic.
StrykerTECH Engineering Staff
Milwaukee, WI
http://www.stryker-tech.com/
RE: Leaking welds on small tubes... precision tig welding help needed
Some of the problems shown in your pictures are the presence of cold laps probably caused by "daub welding". with filler rod that is too big. I also see too much weld metal being deposited.
In addition to the advice given in the posts above I would use a Micro-Tig welding process if you have very many pieces to fabricate.
http://w
RE: Leaking welds on small tubes... precision tig welding help needed
I did note that the tube thickness is only .049". This would cool very rapidly compared to the thicker solid pieces on each end and in the middle... would this cause centerline cracking? That seems to be the biggest problem causing the leaking. Thanks a lot.
RE: Leaking welds on small tubes... precision tig welding help needed
Mike Halloran
Pembroke Pines, FL, USA
RE: Leaking welds on small tubes... precision tig welding help needed
Here two suppliers of Micro-Tig welding wire.
I would look at 312 SS welding wire.
http://www.novatechinc.com/default.html
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