Bombed Weld test 2" sch80 MS pipe with 309SS filler...

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Went down to the UA local this morning to test on 2" sch 80 and 2"  XXS.  It was a disaster, I'm I'm trying to figure out why, as I've had no troubles welding 2" in the past.Here's the setup:2" sch 80 in 6G position30° Bevel, 60° included angle<1/32" root face1/8" root openingBack purge with Ar 5-10 CFH3/32" Tungsten(Tri-Mix), #4 cup with gas lens, with Ar ~25 CFHFreshly ground tungsten electrodes.1/8" 309SS Filler, fresh rods from a certified batch.Lincoln Invertec 350 pro, DCEN, ~60 amps (tryed -10 to +3 with no improvement)  Procedure called for 60-85Should have been a root, 1 fill and cover.  But I couldn't get good penetration on the root.  I called it quits for now until I can get some practice and try again in a few weeks.  (Didn't even try to stick weld the 2" XXS, as I was so out of sorts by the time I gave in...)The procedure called for 3 or 4 tacks, feathered.  I put 3 tacks in and found that the first had cracked.   Alright....  Ground it out and replaced it. Struggled the whole time with the tungsten spitting when lift starting the arc.  Couldn't get the filler to wet in no matter what I did.  It moved like salt water taffy.  If I went hotter, or traveled slower, the bevel would melt away before the filler wet in.  Turning the heat up a bit just resulted in sugaring on the back of the weld, despite taping 3/4 of the root opening to keep the purge gas in place.  Turned the amps down to ~52, and couldn't keep the arc lit.  I've never seen a tungsten spit like these did when striking the arc on the bevel.  I used a die grinder with a small flap wheel to clean some silver coating anti corrosion coating off the bevel, and back at least 1" from the weld joint.  I even cleaned the inside of the joint with the flap drum.  But every time I struck an arc it pitted the bevel surface and would spit yellow sparks for 1-2 seconds.  The tungstens were used, successfully on at least 2 prior occasions, so I don't think there was anything wrong with them.  Made sure the purge gas and shielding gas were on before every start.  I even went back with a file and cleaned the bevels again incase something transfered from the flap wheel to the bevel.  It didn't help...I gave up after putting in the root and then trying to repair a hole in the root pass.  Rather than fix it, I made it worse.  I don't like placing the blame for this on anybody but me.  Does anybody see anything out of place with the weld procedure?  Has anybody ever dealt with this issue of tungsten spitting with lift arc?  Any recomendations for welding with 309 filler on mild steel pipe?I stick welded with stainless filler and managed to produce a respectable joint on 2" sch 80 mild steel pipe.  I've TIG welded on 2" and 6" pipe, using mild steel filler (ER80S-D2) with absolute success on many occasions.I've even welded on 6" pipe with stainless filler(don't recall exactly what kind) and didn't have these issues.Any advice would be appreciated...In the mean time I'm getting some 2" practice pieces and some 1/8" filler to practice on at home...Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Why did you use 1/8" filler?  I would have used 3/32".  It sounds like you just didn't weld hot enough to melt the 1/8" filler smoothly.When doing this, keep your heat on the filler, with very little weaving motion.  With enough heat, it will wet into the carbon steel just fine.  Other than that, weld it just as if it were carbon steel filler.
Reply:I was given the choice of using 3/32" or 1/8", and I thought that the 1/8" filler was what I had used successfully before.  I'll get some of both on Monday and try it both ways.  What amperage setting would you use with 3/32" filler?Would you expect much difference in melting/flow/wetting characteristics between 308, 309, or 316 filler metal?  Any thoughts on the tungsten spitting I saw?Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Turn the heat up and flow the filler in, don't drip it.    Did you punch a small hole to let the purge go so it didn't build up pressure when you closed out?I'd rather be hunting........USE ENOUGH HEAT.......Drifting around Aussie welding more pipe up, for something different.....wanting to get home.
Reply:If more heat resulted in a coked root then you have a problem with the purge. If the purge isn't right you'll never get a good root As said you want a small vent in the purge's exhaust dam and don't forget to turn the purge down before closing up the root pass. Air can get mixed in with the purge when feathering tacks- you need to allow time for the purge to become re-established, as you would before striking the first arc. Was an oxy meter available?The tungsten spitting is odd- did you run through the start up parameters (pre flow, hot start)?
Reply:The top of the pipe assembly was capped, with a 1/8" hole in the center of the cap.  That was the UA's fixture, so I assumed the vent hole was big enough.  I flushed the back purge by turning the flow up to ~15 CFH for about 2 minutes, then back down to 7-10 CFH.  Any lower and I couldn't be certain that the meter wasn't off.I made sure the hot start/arc force control was set to 0; which was labeled 'lift arc'.  Other than the push button that selected which welding process to use, and an amperage control, I didn't see anything else to set or adjust on the power supply.  Now that you mention it, the spitting I experienced does remind me of what happens when you forget to turn on the Argon.  But I never shut off the knob on the torch and I made certain it was open at least 2 full turns so accidental pressure from my hand wouldn't affect the flow.   So I don't see that being the problem...Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:tri-mix? tri-mix what? gas? for tig no wayChuckASME Pressure Vessel welder
Reply:Sorry,  by Tri-Mix I was referring to mixed rare earth tungsten  (Ce/La/???).  These are the only thing they use at Hobart, and according to the instructors are indistinguishable from Thoriated tungstens.  See this link for more info:http://www.diamondground.com/tungmaterials.htmlThese are the actual supplier for the tungstens I used.  I welded successfully for months with them at school.  I've got some red tungstens here at home, and I've been meaning to try them out so I can judge for myself.   Originally Posted by chopper5tri-mix? tri-mix what? gas? for tig no way
Reply:Did you tape off the area you weren't welding?I'd rather be hunting........USE ENOUGH HEAT.......Drifting around Aussie welding more pipe up, for something different.....wanting to get home.
Reply:Yes, I only uncovered one quarter of the joint at a time. Originally Posted by wirehuntDid you tape off the area you weren't welding?
Reply:Intriguing......I'd rather be hunting........USE ENOUGH HEAT.......Drifting around Aussie welding more pipe up, for something different.....wanting to get home.