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well ive been playing with the 350p practicing on 5052 al .078 with ..035 5356 wire. just welding together small coupons maybe 2.5 inches long had a couple crack right down the middle right off the bat and trying to figure out why? been searching and reading no real answer . cleaned with ss brush then i welded the seam flipped over and welded again cracked immediately second one did the same but this time it only cracked 3/4 the rest was strong bent in vise etc was fine. welded a couple others no problem even did a bend on one i burnt 2 holes in and the weld was good no cracking wondering if maybe pulled something in off the table or something on the first two. they were all cut from the same piece of AL can take pics if needed ?? lets hear it350P 30A spool gun cut master 51 syncro 250 other stuff " take a dog off the street and make him prosper and he will not bite you sad the same cannot be said for man" i didnt use punctuation just to piss you off
Reply:Did you back gouge your weld before welding? How about your weld end ? Was it or the first bead concaved? Concaved beads and weld terminations have been the root of most cracked aluminum welds with which I have dealt.
Reply:Aluminum alloys are often rather sensitive to cracking, some more so than others.The 5xxx family is sensitive to cracking, especially if welded with 4043 filler (the magnesium in the 5xxx parent material combines with the silicon in the 4043 filler and forms high levels of brittle Mg2Si, which then crack). The exception is 5052 parent material (what you said you had) which can be welded with 5356 filler if there is enough 5356 filler added to the weld to get the weld bead admixture high enough in magnesium to get 'past' the super-critical alloy mixture ranges. 5052 can also generally be welded with 4043 filler.Pay attention to the 150F service temp limit with the 5xxx alloys (and filler), due to stress corrosion cracking issues.Right from the Lincoln "Aluminum GMAW Welding Guide" c8.100 Page 19:Longitudinal cracking occurs relatively frequently. A radiographof a longitudinal weld crack is shown in Figure 11.Weld cracking can usually be eliminated by taking followingprecautions: Heat treatable alloys are crack sensitive and will crack ifwelded autogenously. Make sure you add filler metal. Make sure you add enough filler metal in welding any alloy. Donot deposit thin, concave groove welds or small or concavefillets. They may crack. Weld passes in both groove welds andfillet welds should be convex. If cracking is encountered in making a square butt weld, trya V-weld preparation. It will allow the addition of more fillermetal. Similarly, if youre using a bevel prep, go to a V-prep. Reduce the clamping pressure to allow the material to moveslightly during solidification. Occasionally high stress is causedby the joint geometry, which may need to be changed.Also note that when running a two-sided weld, you HAVE to back-gouge the first weld pass down to clean sound metal. Failure to do so can easily lead to fusion defects and/or longitudinal cracking.And the usual reminder to watch your crater-fill in order to not have crater-cracking, which may be enough of a crack initiation event in combination with incomplete fusion on an inadequately back-gouged two-sided weld to then progress into a longitudinal crack right down the weld bead.Also note that if the aluminum is/was cut via plasma or laser, that the oxidized cut edges really have to be machined back to clean sound metal before welding. Mostly applies to the heat-treateable alloys. The edge may have to be cut back around 1/8 inch to get past micro-cracks.Similarly, sheared aluminum plate often has 'crud' (oil, grease, etc) in the edges from micro-cracks, and should also be machined back to clean sound metal.Summary: clean well, use 'correct' filler and enough of it, backgouge to clean sound metal before running backside welding pass.http://www.lincolnelectric.com/asset...ture/C8100.pdf The best laid schemes ... Gang oft agley ...
Reply:More info I have in my bookmarkshttp://www.alcotec.com/us/en/educati...num-Alloys.cfmEd Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:thanks guys i figured it may have been cause i welded one side flipped and welded the other without doing anything good to know 350P 30A spool gun cut master 51 syncro 250 other stuff " take a dog off the street and make him prosper and he will not bite you sad the same cannot be said for man" i didnt use punctuation just to piss you off
Reply:umahunter,welding 0.080" with 0.0.35" wire is likely to be kind of hot for that thickness? I'd drop down to 0.030" or 0.025" wire because the power to 'burn' the larger wire seems like it may be too high for the thinner sheet?I'd guess that cracking resulted from too hot a weld in a spray condition? The 350 has modes for thin stuff, but you've not listed the modes or settings so I can't respond if any of those 'machine' factors were in play?My experience implies I'd have used smaller wire in the Power mode 40 if the weld was shaped/whipped but if you prefer to drag/lead a stringer type bead then I'd have tried the various pulsed or pulse/on/pulse modes like # 101 (I think)?If I had a crack in thin material using 5356 wire I'd suspect the weld was too hot- spray mode only- as my first conclusion. Next I'd look to confirm the alloy of the filler as this is common with 4043 in the 50series alloys, not as common with '52 but still happens. Last I'd look at clean up, this thin I don't see back chipping as too big a factor since the bead size is likely to be 2x to 10x the parent metal thickness?Cheers,Kevin MorinKenai, AK
Reply:it was 035 in pulse mode im not sure if i can push 030 since 035 is the smallest urgrove roller i could get for the miller and ive never seen al wire in 025 if you've got a source post up please350P 30A spool gun cut master 51 syncro 250 other stuff " take a dog off the street and make him prosper and he will not bite you sad the same cannot be said for man" i didnt use punctuation just to piss you off
Reply:umahunter, boy did I blow-it reading your original post- or what?My remarks are about the Lincoln 350MP not a Miller so I'm way off base on the mode numbers. I also didn't pay much attention to the MIG torch issue and I apologize. I've been known to ask posters to tell us what they're using and then didn't bother to read well when you did that.I'm using the Lincoln power supply and when I need to get to small wire I use the Cobra SX. http://www.mkprod.com/Prod_CobraSys_sx.htm which, while only rated for steel in 0.023" wire does well in aluminum with the same diameter.My LWS has a really great manager, who goes the extra mile and got me some rolls of 0.025" 5356 a while back.Harris Products Group4501 Quality PlaceMason, OH 45040 http://www.harrisproductsgroup.com/e...-5356-MIG.aspxthey don't even list the 0.025" wire but ...PN 05356D5 120544804 703484 is on this box of wireP/C 10C0316G35 is below that number on the label. The Heat is labeled 29008 and the bar code numbers read; 0 684032 077478 but I have no idea if that is just local to this package?This is 0.025" (0.6mm) in a 5 lb roll (2.27kg) and the hub is the larger size like the 15 lb roll of aluminum or the 45lb. roll of steel. I'm using the MK Python (came with the Lincoln P'wr Mig 350MP) for 0.035" & 0.045" wire and the SX for the smaller sizes.Since the SX rolls don't come for aluminum in the smaller size, I've used the steel rolls regardless of cross section and had no problems.sorry for my incoherent reply above, I can read, just didn't.Cheers,Kevin Morin |
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发表于 2021-8-31 23:50:42