Practice Practice Practice ~ 1/4" Inconel 625

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Welded a couple of 1/4" thick Inc 625 discs using .040" NiCrMo filler.  TIG at 145A with 3/32" Red tungsten and Blue gear.  Last fall, believed these discs were 304SS but recent spark tests and source feedback confirmed they were indeed 625.  Attempts last year resulted in longitudinal cracks.   Alas!  The welds today did not crack.  PreHeated the discs via MAPP for a several minutes. The journey continues  Attached ImagesLast edited by ManoKai; 04-12-2015 at 08:58 PM."Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi
Reply:It kinda looks like a crack on the top pic on the weld to the left?
Reply:Yep, definitely the start of a crack there (is that the old one)?That much 625 is worth a fortune. I remember buying some for an aerospace project back in '06-07 and was absolutely floored at the price. I seem to recall ~$6-8k for a few 8' rods that were maybe 3/4" diameter.Thermal Arc 186 AC/DCHobart Handler 125
Reply:My son used to weld on turbine blades made from Inconel 738.  I think they used Inconel 625 filler.  There were strict limits on interpass temperatures and they welded in a purge box."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Why not weld from each edge towards the center so the crater is in the middle of each stitch?
Reply:Try 1/16 filler.... looks a bit hot.Inco's of any flavor are not a fan of heat... they are NOT like steel and it is Not a good thing to put the boots to them to make the puddle wet out.145 amps may not be bad, but No preheat. Get the puddle started and dab a bit of wire in, let the puddle reform then dab a bit of wire Ect ect ect. You want a flush to convex weld profile, get some metal in the fillet. concave like your pics show will lead to crater cracks, like the tiny one at the end.Loose the preheat and youll be a lot better off, the shiny metal says you have it cleaned good and have good gas coverage. You shouldn't have color inside the drilled hole... The thick plate was 625, the tube was 316SS and the wall thickness was about as much as that penny.... cant remember settings, many moons have past... some where around 100 ish amps and .035 filler of some strange flavor of inco... -Clif
Reply:@ Plasma-Head - thank you for the informative response.  Will up the filler to 1/16" and lose the pre-heat.  Nice beads bro "Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi