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AS A CWI AND RADIOGRAPHIC INSPECTOR IN A COMPANY THAT MANUFACTURES LOW TO HIGH PRESSURE HYDRAULIC TUBING I HAVE COME ACROSS SOME GTAW WELD STOPS THAT I HAVE DEEMED VISUALLY UNACCEPTABLE. WELDS ARE ON CRS AND NORMALLY MADE WITHOUT FILLER METAL. WELDERS AND SUPERVISION QUESTION MY DECISION TO REJECT THESE WELDS WHEN OUR COMPANY SPECS AND MOST CUSTOMER SPECS DO NOT ADDRESS THE SUBJECT. THESE WELD STOPS ARE SHAPED LIKE AN INVERTED CONE AND EXTEND ABOVE THE WELD FACE APP. 0.010" TO 0.020". OTHER THAN REJECTING THESE WELD STOPS FOR EXCESSIVE REINFORCING DO I HAVE ANY OTHER VALID REASON FOR REJECTING THEM ? TO ME THEY ARE STRESS RISERS AND SHOW A GENERAL LACK OF SKILL ON THE WELDERS PART. OUR SPECS DO ALLOW FOR PLANISHING OF EXCESS REINFORCING.
If these are autogenous welds, then it is difficult to understand how you can actually have "excess reinforcement", because there would rather be a lack of weld metal than an excess. My concern would be that if you have this "cone" of metal protruding from the outside surface, then this metal is "gone" from somewhere on the weld where it is needed for strength. Judging from the size you give, I would believe that this too is not a big concern, but confirm with radiographs.
The next problem would be that you could have a "pin hole" inside this arc breaking point. This often happens, but is generally not a problem when the wall thickness is large. As this is hydraulic tubing, it would have a relatively thin wall. I would therefore do some radiographs on these arc breaks to ascertain if they have such defects.
If neither of the problems stated above is present, I would dress the arc break and be happy. Obviously I would also suggest some training for the welders concerned. Performing a decent arc break is not so difficult, so this training need not be more than a couple of pointers from one of your better welders.
Sounds to me like the welder (or more likely his fitter) is "dialing himself down". This would be to reduce the welding current as he is finishing the pass so as not to leave a "fish-eye" by breaking the arc by pulling away the torch. I have worked projects in which this practice was not allowed due to the fact that when dialing down the current fell below the required ranges of the WPS.
I suggest using the acceptance criteria as indicated on the specifications and if a question exists as to the fitness for service of an item related to a condition not addressed in the acceptance criteria, get the opinion of the project engineer.
Have a good day
Advise your welder to not stop unless complete its circle. Good stringing with small dia rod and electorde may improve your joining tube. Are you give its as minimun as heat input that you can.
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