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I'm currently in the middle of a project and I'm working on some fillet welds with the TIG process. The material I'm working with is 2"x1.25"x.125" rectangle tubing and I'm mating a 2"x.120" round tubing perpendicular to 2" side of the rectangle. It's a form fit with a hole saw cut on the end. The rectangle tubing is ~19" long so theres a big base there. The round tubing is 1-15/16" long centered on both ends of the rectangle. So basically I have a fillet weld thats 19"x7/32" and obviously circles around the 2" side of the rectangle tubing.Equipment setupDCENAmps 120'ish3/32" 2% thoriated tungstenArgon gas w/ gas lens and a 3/8" cup3/32" copper coated ER70s Filler / 1/16" non coated steelMy problemThe fillet weld isn't going smoothly. I'm undercutting the crap out of round tubing. The arc doesn't seem to wanna focus for penetration and goes wide. The arc also wanders a bit. I tried to feed it with filler rod fast but it seems to wanna climb round tubing and give me problems.I haven't dabbled with TIG on a regular basis since I first started welding 5 years ago. I took a class just to get a base to learn. My first machine was my TIG and immediately I was producing near perfect welds, including fillet. I dunno where I lost it in the recent years and it's actually kinda agitating. I tried switching between the two different filler rods I listed and notice no difference really. I sharpen my tungsten properly and give it a long point and stick it out about 1/4"-3/8" from the cup. I am new to the gas lens and have been told it allows the tungsten to stick out further. I'm beginning to wonder if sticking it out exposing the tungsten more is causing the wide arc but then again I have had the tungsten out further when I didn't have a gas lens and had no problems before. So I'm not sure.My flat weld portion of the project seems to be good although I did note my weld pool was wider than normal but I was also juicing it to get good penetration which I know I have there but I'm not sure about covering the rounded portion.Also note that the weld area is cleaned well.Looking for any insight as this is a structural weld. If theres anything I haven't covered feel free to ask and I will give my input so I can get sound advice. Also if theres any tips to ensure penetration for a fillet weld using the TIG process I'm all ears.Last edited by Kubs; 01-24-2008 at 04:34 AM.Miller Syncrowave 180SDMillermatic 175
Reply:It sounds like you've done a good job of covering all the bases to a tee. I'm not a TIG expert, still on the learning curve myself, so the only thing that comes to my mind is maybe you're holding too long an arc length (tungsten to work distance). The closer the better, about 1/16" is good. The other idea I'm thinking is try adding the filler to the top part of the puddle, up on the tube, to lessen the undercut on the tube.Like I say, I'm no expert, but I doubt your gas lens is causing the problem. Hope you get it worked out. Sounds like you've thought it out well already.Last edited by DesertRider33; 01-25-2008 at 12:01 AM.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Originally Posted by DesertRider33It sounds like you've done a good job of covering all the bases to a tee. I'm not a TIG expert, still on the learning curve myself, so the only thing that comes to my mind is maybe you're holding too long an arc length (tungsten to work distance). The closer the better, about 1/16" is good. The other idea I'm thinking is try adding the filler to the top part of the puddle, up on the tube, to lessen the undercut on the tube.Like I say, I'm no expert, but I doubt your gas lens is causing the problem. Hope you get it worked out. Sounds like you've thought it out well already.
Reply:Desert,I'll try feeding from the top next time to reduce undercuttingRojo,I was using the 3/32 filler rod primarily, I switched to the 1/16 briefly to see if a control difference would help and other than just feeding faster there wasn't a change.Here's some pics of the finished product. They're control arms for a camaro so I'm looking for some good sound feedback if the weld job is adequate (looking for overkill) for the application they'll be used for. Like I said, it's been awhile since I've TIG'ed and maybe I'm just paranoid that my welds don't look perfect. Sorry I didn't get any shots before I painted. Excuse the quality, my digicam didn't wanna focus and the shots turned out "better" using my cell phone instead. So bare with that. You can see in the 2nd pic where I had some issues.Should prolly also add some scrap pieces I welded together and did a lil destruction test of my own. I welded both sides of the round to the rectangle and grinded off the side I thought had better penetration going for the what I believed to be the weak side to be tested. This is more of a demonstration of the flat weld of the 1.5" weld of the project piece, except on the scrap I was on the 2" section. This result of this was tearing of the rectangle.Last edited by Kubs; 01-25-2008 at 04:44 AM.Miller Syncrowave 180SDMillermatic 175
Reply:Like you said the arc goes wide. Try regrinding the tungsten. A little contamination can do that. Also try a little different angle. Dirt steel seems to contaminate the tungsten very quickly.mm135HTP Invertig 201 With water cooler9" Southbend LatheLots of hand tools.
Reply:On material only .120 thick, especially near an edge, you can typically reduce your amperage quite a bit. 120 amps is on the high side for that. Stick with the 1/16th filler, by the looks of it, you want to keep the puddle a bit smaller. You shouldn't have to dab filler from the topside, that's just a way of compensation for a puddle that is too wide. A 1/16 tungsten wouldn't hurt from a control standpoint, either.
Reply:MY Opinion, too hot! BACK OFF a little, run a smaller bead. or a few smaller beads. 3 little stringers instead of one wide bead. Arc should be not more than one electrode diameter.You are close, try on some scrap.DavidReal world weldin. When I grow up I want to be a tig weldor.
Reply:Thanks for the input guys.OK here is some weld in the raw. I decided to start building another set and as I go post my progress and see what you guys think. I dropped the heat down considerably and have several different welds with various heat ranges. I resharpened my 3/32 tungsten and went at it. Here's the results:Here is 80 Amps using a 3/32 ER70s copper coated filler rod.Shot of the inside of the round tubingHere is 75 amps using a 1/16 non coated steel fillerInside the round tubing againHere is one I did at 70 amps using the 1/16 filler. I didn't finish the pass because I wanted to demonstrate a look down the valley so I could get some opinions to benchmark my performanceInside againAnd lastly here is my fillet weld that I'm most concerned about. 70 amps here with 1/16 filler rodHere's a couple shots from either side to show you so you can examine the corner of the filletI'll appreciate the feedback.Last edited by Kubs; 01-25-2008 at 08:24 PM.Miller Syncrowave 180SDMillermatic 175
Reply:Looks strong. It looks like you could use a bit more gas. I actually like a golden brown color if I can get it. You might also want to try 1/16" filler wire. It will make the weld much hotter, and narrower. Allowing you to penetrate the same, but move along at three times the speed. As you add the thinner wire it does not cool the puddle as much. When you are done adding the wire, and letting it burn in and level out, you can cool the puddle by coming off the pedal. It looks like you are moving along really slowly and creating a really wide hot area. Which is not terrible. But most prefer a more narrow weld. Sincerely, William McCormick
Reply:I just realized you are using 1/16" filler wire. It looks like it is going on cold to me. Like you are using a larger wire. Sincerely, William McCormick
Reply:Ha-ha, now I understand you are using both types. Where you used the 3/32" it looks like it went on just a little cold. Sincerely, William McCormick
Reply:KubsIn most cases the weld you made below would be perfectly accepable in the sense that it is is tied in nicely and flat to convex shaped. However in this case the item is structurally significant. I think of tig as a 'finess' form rather than just rapid production. If I was to do that joint I would put a 45 degree bevel on the rectangular tube, run a quick pass to fill groove, then run a fillet like you've done over top and never think twice about it. Attached Images
Reply:Originally Posted by William McCormick JrHa-ha, now I understand you are using both types. Where you used the 3/32" it looks like it went on just a little cold. Sincerely, William McCormick
Reply:I think your welds look good. MUCH better than the first attempt. In MY opinion, they are fine. I would dip more often. With the heat down, it looks much better and I see no undercutting.Is that a control arm bushing mount?DavidReal world weldin. When I grow up I want to be a tig weldor.
Reply:The 1/16" filler wire definitely looked better. But still a bit cold for something very important. You might want to as the other fellow mentioned dip more often. Or Heat add wire cool, and move many more times in tiny increments. This creates better mixing of the filler and base metal. Because you will not be adding globes of filler wire, and overpowering the base material. They are two different things. The filler wire is supposed to be added to rejuvenate the base material, add cleansing agents and to bring the weld up to the level of the surface. It is not really made to be globed on. Years ago a weld was a weld, one pass. Many passes was considered something you needed a black smith license for. One thing I was always taught was that on structural it is better to be a bit hot then a bit cold. A little undercut is not your enemy. Take a look at many factory made parts they know that hot is better then not undercut. I also noticed that you put most of the heat into the rectangular tube. When most of the heat should have been into the round tube. Which ever piece meets with a cut edge that is the edge you want to keep the heat away from. You want to add the heat to the flat uncut surface. That is why you were getting the undercut in the tube. It was cold and feeding the puddle. You might be surprised how long it takes to get a puddle like that though without filler wire. Most people get nervous and just start to add filler wire or put the heat on the cut edge and add wire. Sincerely, William McCormick
Reply:Originally Posted by David RI think your welds look good. MUCH better than the first attempt. In MY opinion, they are fine. I would dip more often. With the heat down, it looks much better and I see no undercutting.Is that a control arm bushing mount?David
Reply:If all the welds are done like that 1/16th @ 70 amps, on a set of rear control arms, you will have no problems with reliability at all.
Reply:Originally Posted by SupeIf all the welds are done like that 1/16th @ 70 amps, on a set of rear control arms, you will have no problems with reliability at all.
Reply:I think Supe is saying go around the whole bushing mount just like that both sides. I don't see Any undercutting.DavidReal world weldin. When I grow up I want to be a tig weldor.
Reply:Originally Posted by Kubs
Reply:Originally Posted by David RI think Supe is saying go around the whole bushing mount just like that both sides. I don't see Any undercutting.David
Reply:Originally Posted by William McCormick JrWe always leave that edge straight and do not bevel it. The edge that is left will wash in and you will need less filler wire. That is how we do it. Sometimes if we machine or bore the part, it causes sharp edges. If it does we grind them back straight. But we do not chamfer or grind them past 90 degrees. I did not realize the square tubing was thicker then the round tubing. That is not always preferable when welding things together. It is best to keep the material the same thickness when designing if possible. It would be like welding a thick wall pipe to a thin flange. In the thin flange scenario you realize, that is not such a good idea with all that leverage on a thin plate. One and one quarter inch pipe, schedule forty, welded with 7018 rod, to an approved flange 11/16" thick, five and one quarter inches round, is rated for 600 pounds using true engineering standards. I just posted this to give you an idea of the strength of the lever. Often when destructive testing and designing they lighten up the arms so they give or flex as well. And do not just put an unyielding tearing force on the weld to the main branch pipe or tube. Sincerely, William McCormick
Reply:This is a test piece I did. It is hot rolled and a little pitted. I cleaned it up, but it was still pitted. It came out pretty good though. I would be happy if a run of parts looked like this. I went a little heavy on the square piece myself, Ha-ha. Sincerely, William McCormickLast edited by William McCormick Jr; 01-26-2008 at 10:41 PM.
Reply:Yea, at that angle it creates an optical illusion or something. If I had not said something to you this morning about putting a lot of heat into the tube. I would have gone out and undercut the tube by a mile. That was with me purposely keeping the heat on the pipe. Ha-ha. Good practice test! Sincerely, William McCormick
Reply:I used pretty low amperage to that. I would say about 90 amps at most. Probably less. I start off slowly letting the part get some heat in it. And then I go a little faster once it is hot. I used a number 7 gas lens and 20 cubic feet an hour. Sincerely, William McCormickHere is another one, that I put more heat into the round tube. You can see it is much nicer. Sincerely, William McCormick
Reply:I was in mid range on a Linde 305, and I turned down the master power dial, so that I decreased the amount of amps that the foot pedal can call for. However I increased the amount of control I had with the foot pedal. Instead of the foot pedal going from 0-175 or whatever the mid range setting is. The foot pedal now went from 0-100 amps Giving me more control of the heat. I could be a little off with the pedal and not blow a hole or burn the metal. With more foot pedal movement it is much easier to heat and cool the puddle. Sincerely, William McCormick
Reply:William McCormick JrMaybe it's just my nature to overbuild. The pass you ran on the top side appears to have fused nicely but the concave shape doesn't offer any extra reinforcement. I'd normally run a convex cover pass. Can't tell along the side but I'd fit it up so a full thickness was showing before welding. Attached Images
Reply:Originally Posted by OldSparksWilliam McCormick JrMaybe it's just my nature to overbuild. The pass you ran on the top side appears to have fused nicely but the concave shape doesn't offer any extra reinforcement. I'd normally run a convex cover pass. Can't tell along the side but I'd fit it up so a full thickness was showing before welding.
Reply:Duplicate post
Reply:Duplicate post
Reply:Originally Posted by OldSparksWilliam McCormick JrMaybe it's just my nature to overbuild. The pass you ran on the top side appears to have fused nicely but the concave shape doesn't offer any extra reinforcement. I'd normally run a convex cover pass. Can't tell along the side but I'd fit it up so a full thickness was showing before welding.
Reply:Originally Posted by OldSparksWilliam McCormick JrMaybe it's just my nature to overbuild. The pass you ran on the top side appears to have fused nicely but the concave shape doesn't offer any extra reinforcement. I'd normally run a convex cover pass. Can't tell along the side but I'd fit it up so a full thickness was showing before welding.
Reply:I honestly don't know what to say. On the left we have the manufacturer's product. On the right a typical full pen boiler tube butt. How the blue one comes out being better then the other is beyond me. Attached Images
Reply:If you look at that cap welded pipe, you will see that the weld also shrinks the diameter of the pipe right next to the weld. This adds to the weakness of the material or compounds the weakness of the material next to the weld. With TIG welding done slowly you actually raise the pipe a bit or expand it. And equalize the weakness created. It is also great for sanding and polishing. Sincerely, William McCormick
Reply:Simply amazing what you can learn on the internet.
Reply:Very interesting. So a strong TIG weld will be flat or slightly concave then? And not convexed because the heat, like you said (if I'm understanding this) will draw from base material and thin it out and break right next to the weld, correct?I'll contribute more to this thread with some welds I'll produce and see where we're at. BTW, I found my very first fillet weld when I finished my welding class and purchased my TIG. This is a control arm bracket I had made by a machine shop. They had their welder weld these up cuz at the time I had these made I had zero experience with welding and were made before I decided to learn.Here's the welds they had (red) that I was welding over. Obviously mine cracked because I was welding over a cracked weld, but I only used this piece as scrap to practice on. So keep in mind I wasn't trying to make any use of this as I bent and broke the weld.This is my fillet weld over top of their existing weld. I just wanna get some feedback if this is the direction I should be genuinely trying to get myself back to.Here's a shot of the inside showing the penetration I potentially achieved. I say potentially because I wasn't striving for it at the time. I was just practicing welding and this is the only section that I penetrated all the way through.Miller Syncrowave 180SDMillermatic 175
Reply:Kubs, don't believe everything you read- ESPECIALLY when it's on the internet!this link is to a book preview, with a few words on the subject...http://books.google.com/books?id=TFt...2hte1hjTJil6a4the open corner weld you posted is under filled. if you cut it in half (across the weld) you'll see the weld has less cross-sectional area than the base metal. the parts intended use will determine whether that's acceptable or not
Reply:Now I'm really confused Originally Posted by hotrodderKubs, don't believe everything you read- ESPECIALLY when it's on the internet!this link is to a book preview, with a few words on the subject...http://books.google.com/books?id=TFt...2hte1hjTJil6a4the open corner weld you posted is under filled. if you cut it in half (across the weld) you'll see the weld has less cross-sectional area than the base metal. the parts intended use will determine whether that's acceptable or not
Reply:Originally Posted by hotrodderKubs, don't believe everything you read- ESPECIALLY when it's on the internet!this link is to a book preview, with a few words on the subject...http://books.google.com/books?id=TFt...2hte1hjTJil6a4the open corner weld you posted is under filled. if you cut it in half (across the weld) you'll see the weld has less cross-sectional area than the base metal. the parts intended use will determine whether that's acceptable or not
Reply:A weld bead should be as wide as it is deep. The cross section should be reasonably square because when it shrinks, it will shrink the same in both directions. This will crate the least stress. Flat across the top is pretty much the best. More (convex) is a waste of time and material. Less and the weld is not as strong as it could be because the throat is shallow.It don't matter to me what you use to put the bead down.DavidReal world weldin. When I grow up I want to be a tig weldor.
Reply:Here is a movie of me destroying that piece of steel I TIG welded. It did not take much to do it. http://www.Rockwelder.com/Welding/St.../SteelTIG.htmlAll the welds held. Sincerely, William McCormick
Reply:Originally Posted by William McCormick JrHere is a movie of me destroying that piece of steel I TIG welded. It did not take much to do it. http://www.Rockwelder.com/Welding/St.../SteelTIG.htmlAll the welds held. Sincerely, William McCormick
Reply:Going back to the original question: It is recommended to blunt the sharpened tungsten slightly for carbon steel. A sharp point is for stainless steel. I don't know if you solved your arc wander problem, but this may help in that situation.SA200,Ranger8,Trailblazer251NT,MM250,Dayton225AC,T D-XL75,SpoolMate3545SGA100C,HF-15-1 RFCS-14 When I stick it, it stays stuck!
Reply:Kubs, What ever works for you to get a good bead. Pushing the filler into the base metal is not going to achieve more penetration. You need to fuse the filler to the plate. It has to be a mix of base metal and filler. If you get fusion, penetration isn't as important. Dip the filler, STAB the filler, or STICK the filler, as long as the heat is right and you have enough filler in the right place.DavidReal world weldin. When I grow up I want to be a tig weldor.
Reply:Originally Posted by mooseyeGoing back to the original question: It is recommended to blunt the sharpened tungsten slightly for carbon steel. A sharp point is for stainless steel. I don't know if you solved your arc wander problem, but this may help in that situation.
Reply:Originally Posted by RojodiabloSharp points for everything. Aluminum, steel, Ti, SS, all of it. And Kubs, any welding book with a cross section picture will show exactly what David is saying, and where some other information is misguided. If you are looking for strength in the weld, figure to not have any undercut if at all possible. A concave weld is one where material has been pulled from the base material to fill the joint. Which does not hurt it as much with SS, but on a chassis part on a car, I would not let those kinds of concaved welds fly. The junction is thinner than the base material, especially when you consider you can only weld ONE side of the material. In the case of a one side t-joint weld, or a tube weld, you'll want the bead to be as thick as the thinnest piece of base metal, or roughly equal to the cross section of the 2 pieces, again, as David suggested. All I can say is-filler is not so expensive as to skimp on it, especially if your life depends on the part holding. I'd trust an ugly stick weld, or a bulky mig weld before I trust a very pretty but undercut tig weld.
Reply:As far as my arc wandering since I backed the amperage down the arc is much more controllable. 120A was a bit on the insane side, I guess I wasn't patient enough at the time. The <80A range works much better. Think I'll kick it up to 90 just to have something to play with if need be and just feather the pedal. I'll give everything another go around wednesday when I have time and post results.Miller Syncrowave 180SDMillermatic 175
Reply:I did a test on penetration and fusion. See projects and pictures section.I grind a flat on the tip of my tungsten for 3 reasons. 1. It keeps it from balling2. I can SEE it better3. The point is the last piece to get sharp. If there is any contamination there, I want it gone. Everybody has their own way. I find even with aluminum 2% thorated will try to ball. The small flat seems to keep it under control.DavidReal world weldin. When I grow up I want to be a tig weldor.
Reply:They are talking about if you need more penetration. To blunt the end. If your tungsten is 3/32" and you are welding 1/8" steel material. I doubt you need to blunt it. Unless your power supply is pulsing DC current. Then the tungsten might ball at any amperage. I have not done a great deal of DC welding with Miller equipment. However with a water cooled torch, and using amperage in the range for that tungsten diameter, you can certainly point the tungsten. It does not go anywhere, if you are using a safe amount of coverage gas. I have tried the blunt point, I did not like how the gas flowed around it. Sincerely, William McCormick |
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发表于 2021-9-1 00:02:41