Weld cracked Advise pls

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Nicest TIG weld I've laid to date and it crackedBut mommy it's just a tiny crack.Machine TA 211iFiller 1/8" 304 SSTSetting 176 ampsBase metal 3/8"   A 36 Steel Pics:What do ya think caused this.  It's just on the place where I ended the weld.
Reply:Use 309ss, or just mild 70-s2, that might help. Maybe 140A or lessSqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:its at the begining not the end and looks like you need to add more filler instead of trying to fuse it together
Reply:Originally Posted by abecits at the begining not the end and looks like you need to add more filler instead of trying to fuse it together
Reply:Your weld has a lot of undercut on the top toe of the weld. It also has a crater hole at the end. The crack started right at that hole that was left at the end. Eliminate those defects and the cracking will be gone. Why are you using expensive stainless tig rod to weld mild steel? Get yourself some 70S-2 tig rod for welding mils steel and save yourself some $.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:All my welds crack. Send it down the line.
Reply:Any chance we can agree that the crack is at the beginning of the weld.  At first I thought the bead profile was convex and although it had quite a bit of undercut, wouldn't expect it to crack.  Think now that the profile was severely concave and had very little reinforcement.  Would have been a good learning example to have clobbered it with a hammer and shown the broken end view.  170 amps will work but is not necessary.  You're still learning.  Try 100 and work on feeding wire to get buildup and consistency.
Reply:Looks to me like to long of an arc length, which leads to incomplete root fusion and cracking. Just my two cents.Thermal arc 211iCk flex-loc 150 & 130Clamps, saws & grindersHarbor freight 80 amp inverter
Reply:Lots of input.  ThanksI'm using the SST wire coz that  was what was lying on my tablestart then back fill?  OK Less power?  OK
Reply:The crack did start at the beginning of the weld. Regardless, the crater hole left there is what caused the crack to start. Using stainless rod to weld 2 pieces of mild carbon steel didn't help neither. All the undercut isn't making things much better.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:The crack stayed in that one section and  did not propagate through the rest of the little fillets or whatever the proper term is for each new puddle that looks like some kind of frozen metal wave.
Reply:Lincoln do a Poster on why welds crack http://www.lincolnelectric.com/asset...ture/WC515.pdf
Reply:Nice chart Gerry, looks like over penetration due to too many amps and not enough filler = centerline crack.SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A