Identifying penatration welding aluminum

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Im gearing up to start a project, all aluminum tig.  Ive built some things since i got my syncro250 over a year ago.  They are not super structural but they are holding up great.  I had one butt weld fail, i blame that on grinding smooth and not ving out the materials.Anyways.  Im wondering what visual signs, are proof that you are penetrating well into both pieces.  I mocked up this channel, and square tube as this is what most of the weld will be.Looking through the tube, i see two heat affected zones.  The square is .125 material, and the channel is .130.I need to work on my weld spacing, and positioning.  I shake and hold my breath, im looking to get zaps gloves or a tig finger for better stabilty.  Any other suggestions?Machine is a syncro250.  3/32 tung, 2% lanthanated.  I cant remember what diameter filler,  prob about 17 cfh, 7 ac balance, and pedal. Attached Images
Reply:Why not do a little destructive testing to see how you fair? Make a fillet weld, clamp it down and smack the backside of the top plate with a hammer, look to see how much penetration your weld got.http://www.esabna.com/us/en/educatio...g-of-Welds.cfmDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Cant help you with the destructive testing, I usually just give things the old 3 foot drop test. But I can tell you I have built lots of aluminum stuff with a syncro 250. My coworkers are pretty rough on things and they all seem to hold up well. My set up for that joint would be, 3/32 ceriated, balance 7, 180 amps, 1/16 filler. Mash the pedal at the start and back off as you go. If you cant fix it with a hammer, it must be an electrical problem."Boy, everyone starts with a full bag of luck and an empty bag of experience. The trick is to fill the bag of experience before the bag of luck is empty."-Grandad circa 1990ish
Reply:I'm a big believer in breaking things.When I first got my Dynasty I played with different settings, and some destructive testing to find what worked best for me. Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:You can also cut the weld apart and buff the edge of it and use a mixture of water and draino and it will show how deep your filler is melting into the parent materail
Reply:Is an aluminum weld more likely to break at the weld seam?
Reply:Ive smashed some stuff in the past, with good results.  I guess I'm looking to far into it.  Just want the project to last a long time though.
Reply:brendonv, it's better practice on aluminum to prepare the main (80-90% ) of the joint penetration by shaping the edges of the material.IN the case of the channel to square tube butt, a sanded/sawn/dressed bevel of 95-100% of the channel's thickness at an angle that allowed TIG arc to wet the entire parent metal face would be a better joint.In the back-bend of the T fillet shown by CEP, the strength would have been much higher if the vertical piece's lower edge were beveled to allow a root face of the entire thickness of the material.  Gas pockets shown in that broken weld cross section are reduce somewhat by the 'huddling chamber' of the hot argon in the beveled space created by the mechanically trimmed material.Since aluminum freezes so fast- short time from molten to solid- the more the mechanically formed weld joint cross section can provide an increased face area for the arc to 'wet'' the stronger, cleaner and deeper the weld resulting will hold the parent material under more load.Here is a butt of one piece to another without any bevel and a look at the area of the root face.  Notice the high build up and the low penetration of the root face? (color is used to visually separate items in the illustration)Here is another joint prep for a similar joint, this prep leaves a little of the parent metal out; by beveling the butt end- so the fast chilling weld can be deposited directly onto the parent metal at a deeper location, therefore, the final weld has an increased root face area and is stronger.And here are a few cross sections of the results of the different joint cross sections. This comparison shows a couple of weld cross sections to illustrate the root face area comparison, when compared to the top most (non-beveled) joint, I think the reason for weld bevels in aluminum are more obvious.If you add more heat/wattage/amperage/power to the welds, in these various cross sections weld joint preps, then a given weld will melt or fuse deeper, that the same preparation with less heat energy.Here, another weld could have reached "all the way" down to the lower most V area and 'sagged' or created a back weld inside the right hand tube.  Mechanical preparation is not a substitute for good welding, but it sure can make a joint stronger than just "cut-butt-& weld"So, while inverter arc controls like Balance, and higher frequencies (>60 Hz) can help create narrower and deeper welds, in general; it's best practice to provide some bevel/"V"/gouged shape/root face excavation (all terms used to describe this practice) so the arc will wet open faces of parent metal to a deeper depth into parent material.I hope this helps some with your exploration of joint strength in aluminum TIG welds?Cheers,Kevin MorinKenai, AK
Reply:Yes, thank you.  I caught your other pics regarding fitment on another thread.  Awesome.  I find myself checking out aluminum wleds all the time.  The welds on my aluminum flatbed, which was six grand, are unbelievable.  Trying to get mine dialed, and possibly sell what i am going to be building in the future.Will an aluminum weld mostly break at the filler though?  I cant imagine the parent metal being weaker, unless from something like vibration over a period of time.
Reply:I actually prepped that channel before welding, not quite as much as you show though.  I beveled the top 1/16, the material was 1/8.  I will try some with a full bevel.  ( hard for me to word this correctly)
Reply:Originally Posted by brendonvIm gearing up to start a project, all aluminum tig.  Ive built some things since i got my syncro250 over a year ago.  They are not super structural but they are holding up great.  I had one butt weld fail, i blame that on grinding smooth and not ving out the materials.Anyways.  Im wondering what visual signs, are proof that you are penetrating well into both pieces.  I mocked up this channel, and square tube as this is what most of the weld will be.Looking through the tube, i see two heat affected zones.  The square is .125 material, and the channel is .130.I need to work on my weld spacing, and positioning.  I shake and hold my breath, im looking to get zaps gloves or a tig finger for better stabilty.  Any other suggestions?Machine is a syncro250.  3/32 tung, 2% lanthanated.  I cant remember what diameter filler,  prob about 17 cfh, 7 ac balance, and pedal.
Reply:Originally Posted by weedenbI'm going through a similar process of learning on the mig side of aluminum and this is what I've experienced so far. As far as forensic analysis goes I find that simple cut sections work very well, just cut through one of your welds and polish the face up a bit until the pattern shows. Even without etching or dye's the fusion and penetration are pretty evident. I just cut through a piece with my bandsaw and then sand it down some with my cheapo Skil belt sander. This is some 1/4" 6061 and 3/16" and 1/8" 5086 welded with 3/64" 4943 using default voltage and wire speed (amps). As you can see from the photo, the 1/4" doesn't quite get to the root, the 1/8" is a bit too hot and is deforming the back side but the 3/16" in the middle appears just about right in my mind? My goal is to see if I can dial these in just using straight voltage and wire speed before I jump off the deep end messing with the arc control and pulse features that my rig offers (MM350P). I'm pretty sure I will need to follow Kevin's advice and bevel the 1/4" at least to get where I want. I know my welder could get the penetration I want to see but the side effects from the needless extra heat wouldn't be worth it. On the thin side I'll probably get to play with the fancy stuff my 350 offers but I'm still searching for that boundary where I really need to.As far as destructive testing, by all means beat it to death and see what happens! In my experience, given proper prep, fit, filler selection and a reasonable weld quality these joints will all fail at the thinnest section not the bead. For the tee joints in the picture, all will ultimately fail in a V pattern zone near the parent metal-filler boundary. This is both the thinnest section and the maximum HAZ effect.Good luck!
Reply:Great posts, thanks guys.
Reply:Originally Posted by brendonvWill an aluminum weld mostly break at the filler though?  I cant imagine the parent metal being weaker, unless from something like vibration over a period of time.
Reply:Originally Posted by MinnesotaDaveI consider your 1/4" weld a pass - it's fully fused to the root and has a decent profile.Penetrating all the way through so the welds touch should not generally be needed.From lincoln:http://www.lincolnelectric.com/en-us...netration.aspx
Reply:Weed, brendon, Dave, AK,using the image of the back to back fillet from Lincoln, I'll make a few points that have shown up in my boat building experience to be important.If the two 'legs' are the root faces that fuse the weld and parent metal are the source of the strength of the welding process (?) then by folding the two welds shown at the hinge point of the label "Weld Root" you can keep the same fusion strength but reduce the net weld size.If the two 'Weld Root' points are moved toward one another the Face distance can be reduced while keeping the to 'leg' areas the same.  Once the 'leg' distance is reduced the effect of contraction on the parent metal hull panels to the left and the right of the welds shown is reduced. The length of the two 'leg' distances are the primary source of pull on the adjacent panels. If that lever is reduced the pull is reduced.If the 'face' distance is reduced then contraction pulling on the toe and top (ends of the 'legs') is reduced; because the leverage of a wider face is pulling farther from the T vertical therefore it has more pull on the material to the left and right of the welds.  Controlling weld deformation of the parent metal in a weld aluminum boat (the subject of my remarks) is a matter of properly preparing the weld zone so that the cooling contraction is reduced to a minimum.The next thing is about 'print through' or the bulge of the weld seam outside the bottom of the T fillet coupons shown above. Again, if the weld is smaller in cross section proportional to the parent metal scantlings; then the amount of heat, expansion and contraction is reduced.  So the bulge or print through can be reduced by; smaller weld section with less mass or filler and therefore less all up heat to deposit the weld.However, even if the final welds are smaller than shown in the back to back weld illustration they can retain the same leg length or (root face) area by gouging a weld deposit area so the eventual face is reduced in width without loosing the area of the weld fused to parent metal.  These two welds will print through less than the larger, wider spread welds of larger cross section and this is illustrated in the three sections of weld above.The three weld sets are not uniform in proportion, they all do the job they're all strong enough to hold but they could be adjusted in section and prep to make all of them 1/2 their current size resulting in less distortion, just as much strength, and less print through.The way to adjust MIG beads is by travel speed, but to speed up the travel, it may be necessary to add wire and amperage/voltage/wattage and that is sometimes counter intuitive.  For example if you can position a hull bulkhead weld as a down hand weld (rotisserie fixture, hanging the skiff by the gunwales) so that long fast welds can be done easily; 0.045" 5356 wire on 5086 1/8" to 1/8" fillets can be put down that have a 'face' dimension of 1/8" and fully fuse the two hull panels with very minimal print through but full strength.But this same weld is nearly impossible if the weld is horizontally oriented and without a uniform, clean, Vixen filed, beveled edge on the T piece in the fillet.  I could only do these welds on the skiffs I've built if they were positioned down hand so that I could weld 30-36" long welds in a single pass in about a 8-10 count.   So in regard MIG, prep is still the best control of the effects of weld deformation and in terms of TIG by reducing the 'leg' not only does a smaller mass of weld get deposited that reduced size is the same strength, less entrainment, and faster to put down reducing the overall effects of the TIG welds' increased heat.For these reasons I use a cold wire feed TIG gun that allows TIG welds at MIG speeds. Coupled with gouged out weld prep and carefully applied series of welds- entire boat hulls can be welded with TIG still resulting in smooth hulls.For my work I prefer to bevel these types of aluminum joints so the prep goes to 'bury' the weld so that penetration is coupled with the reduced distortion of smaller welds that are deposited faster and with less cost.Cheers,Kevin MorinKenai, AK
Reply:Very well stated Kevin! My best results always had the smallest bead face but with a maximum root area. Your phrase "bury the weld" fits well. Print through may be admired in some applications as a sign of good penetration but it certainly doesn't fly in boat hulls  I can get by okay with 3/16" and above but 1/8" certainly kicks my butt for reasons you noted. I'm going to keep playing around with it, with my new welder at least I now have a stable repeatable base to work from when varying parameters. My old rig is a good unit but the concept of getting all your settings back to a known precise point wasn't very realistic day to day, pretty much had to rediscover what worked best each time you picked up the gun. I've been goofing around with 4943 and I really love it but I guess its time to put back in some 5356 which is more appropriate for the 5086 plate and get down to business with the 1/8" challenge. I have a new spool of 0.035" Maxal 5356 I've been itching to try out on the new rig but I never had that much luck on my old rig going smaller than 0.045" with 5356 wire, what's your experience in using smaller wire on the thin sections? Brendon, sorry to hijack your thread but I think this is good stuff for tig also
Reply:So ive been thinking.Above there is mention of appropriate weld size.Would there be a chart showing ideal weld size/width in comparison to the size of material being welded?Such as if your welding 1/8" material, your weld should be 3/16" wide...or something along those lines?
Reply:Usually it goes say  a 1/4inch to 1/4 inch fillet should have a min throat of 1/4inch  so it follows the thickness of the thinnest material in the joint
Reply:They way you get 'penetration' on aluminum is by letting it keyhole before you add filler. It doesn't really burn in like on steels because the heat sucks out of the area. You have to V the joint or use a ton of heat and add filler slowly right as it keyholes.Welding/Fab Pics: www.UtahWeld.com
Reply:Playing around today before starting to do final welding on those truck sides.  Messing about with bending.  Really mashing the pedal on these it seems.  Not much crown on the weld beads, had a hard time keeping the keyhole filled with 3/32" filler even. Attached Images
Reply:Next time show the roots before you bend as well. Beads look like they may have penetrated semi decently to the back on those but welds.  The lower one looks like the penetration may have been favoring one side more than the other. Hard to tell in those picts well.Keep in mind jammed tight but welds are some of the hardest to do well. A bit of bevel or gap can help greatly on getting full penetration. You want to see a nice even line of reinforcement on the back and no sign of the original cut edge when done..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Thank you.  I beveled them to a 45 about 2/3 of the thickness of material.Above there was mention of having no buldge in certain circumstances.  The peices welded with buldge were significantly harder to bend than with those without during my "test"Aluminum is tough to understand!