Ultrsonic Tested Spray Arc Welds

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I Have A Question About Ultrasonic Tested Welds. Where I Work Once In Awhile I Am Required To Put Down Welds Manually That Will Be Tested Using The Ultrasonic Testing Method. I Use The Spray Arc Method With .052 Wire And 85/15 Argon Gas. The Weld Is 2 3/8in  Plates With A 1/2 In Gap With A Backing Strip. I Use 5 Beads To Complete The Weld. 1 Root Pass On Each Plate And 1 Weld In Center And 1 Weave Bead Cover Pass. The Weld Is About 3 Feet Long. I Need Any Tips On Better Techniques. These Welds Used To Be Welded By A Robot. The Robot Never Cleans The Silicone Residue. The Robot Uses The Pulse Arc Method. When The Welds Are Put In Manually We Are Instructed To Clean All Silicone And Non Relative Material. The Robot Has Passed The Ut Welds Before. I Want To Know How It Is Possible That The Robot Can Put This Weld In Complete With No Cleaning. This Is Not A Normal Ut Weld It Is Very Critical With A Very High Standard. The Weld Must Be Basically Perfect. Thanks
Reply:Didnt know you could get rid of silicon.  Its in the filler wire and doesnt burn off.  dunno.  Think you may have to wire brush it off (I tried it once, and the stuff doesnt budge very easily).  Im a new at this, so am curious as to what the answer would be myself.Various GrindersVictor Journeyman torch200cf Acet. 250cf oxygenLincoln 175 plus/alpha2 gunLincoln v205t tigLincoln 350mpEsab 650 plasmaWhen you can get up in the morning, Its a good day.Live each day like its your last.
Reply:If you are doing something critical like a weld test remove the glass ( silicon ) on the surface of your weld bead between each pass.  You don't really have to do this but it is good insurance.  I do it every time I test.  Only five passes in 2 3/8 material is not very many passes.  By my math that is .475 inches buildup on each pass.  I think you are asking for cold lap or some kind of lack of fusion at the edges by building up so fast.  I would be doing closer to ten or more passes.  Also a wide weave is risky.  I am guessing the cap pass would be well over an inch wide???  A half inch build up like you describe is something only I have seen with submerged arc.  I suspect a robot might get away with it on pulse but I sure wouldn't.
Reply:the material is (3/8) right, not (2 3/8) ????
Reply:Originally Posted by marvin... The Robot Never Cleans The Silicone Residue. ... We Are Instructed To Clean All Silicone And Non Relative Material.
Reply:A good clarification on terminology ... thank you.  Sorry I misunderstood about thickness.
Reply:Originally Posted by Tensaiteki2) Why do you capitalize every single word?
Reply:Originally Posted by brownyThat's what the board software converts the post to if all the text is upper case.
Reply:Originally Posted by TensaitekiWhile a hand brush will remove the silica islands, it takes a lot of work and time. I find that the best (and fastest) method is to use a wire-wheel on an angle-grinder. However a powered wire-brush should never be used on something that will be tested with dye-penetrant (PT). Powered wire-brushing should not cause any problems with welds to be inspected ultrasonically (UT).
Reply:I prefer the point of a carbide tipped scriber or the sharp point of a chipping hammer dragged down the bead.  I then wisk the bits of glass ( silica :'))) off.  A grinder disc on edge is also fast.  To get a wire brush to remove the glass it has to be a very coarse knotted type and it takes a bit longer.  Three feet is a long run to do by hand.  I would take great care at my stop starts.
Reply:Originally Posted by enlpckWhy do you say powered brushed shouldn't be used on welds  where  PT is used? Does this apply to all passes or only to cover passes?