stick welding stainless pipe

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I have a project were we have to weld 300' of 304 stainless 8" screens. Im using a utp 308L rod. we are butt jointing the sections and the pipe is in the vertical position running them down a water well. when your running two passes, root and filler, on stainless what is the best way to do this do you need to peen it or just nock your slag off and run over it again?
Reply:Sounds like interesting job.       Figuring stainless pulls hard , and smaw burns hot, figuring your using long lengths of pipe to go down well,  warpage may work into the concern.     It may need be welded 180 off between passes to try to contol it.    And if warpage is a big enemy, some preheat might be appreciated.       However ,  I haven't done it.     So only take it as a suggestion.        Just out of curiousosity, can to describe joint types to what wall thicknesses?
Reply:idacalSome questions ?Is this a vertical pipe into a well 300 feet long ?If so, is there a requirement to weld the butt welds full pen ?Would like to assist if I can.
Reply:I've welded Many steel well casings in wells up to 800 foot for water and non of them were stainless.   I too would like to know a little more about this job.  Sounds interesting.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:We do quite a lot of stainless piping with sticks in the oilfield. This is how I do it. Fairly wide gap on the root and run uphill. Brush it and grind out any wagon tracks and run the next pass. Same thing for any additional passes. No peening required. Horizontals shouldn't be much different. In construction the stainless was all done with tig.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:its for a municipal well that the water ate holes all the way through .375 wall casing in 15 years. we  installed all 300'  to day with no problems I was just wondering how others weld stainless pipe. I had one job I went to fix, that after the Stainless screens and steel casing were installed we ran a camera survey down it and every single one of of the field welded joints steel to stainless had failed, about a 70,000.00 dollar loss. I couldnt figure out how the welds broke like that. the crew blamed it on triple passing the weld I figured they welded it and instantly submerged it in drill mud and crystalized it (dont know the proper terminology).answer to 123weld    It was sch 40 pipe we were running two welders one on each side of pipe then waiting until metal tempeture was below 220 degrees before putting any strain on the welds and lowering them in. Its just a little less than full penetration you start gapping welds it takes a whole lot longer but is lot better weld . we were running 110 amps on 1/8" rodLast edited by idacal; 07-30-2008 at 09:16 PM.
Reply:Mild steel to stainless steel will fail unless done with high nickel rod like 309 or even 312.  If they were done with 308 they likely had a brittle failure as you describe.  300 series stainless by itself with no carbon steel does not need to hang at high temp... in fact a quenching it will not be a problem since it has no carbon.... there must be an expert around who could expand on this.Last edited by lotechman; 07-31-2008 at 12:03 PM.