The seal welding or back welding of threaded joints is not a new method. However caveats posted previously do apply. However if you are in a high fatige enviroment back welding helps but will not eliminate the localized stress concentration that builds up at he the sharp v notch of the thread root. I have seen published data taht indicates this stress concentration to be on the order 0f 6 or 8.
If you are in a fatige enviroment use socket or better yet butt welds.
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Best Regards,
John C. Luf