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Hi there. This is my first post on this forum and I thought I'd post a brief introduction here before I get to my question asking I'm 27, live in Melbourne, Australia and work as an Auto Electrician/Installer. Messing around with cars has been a hobby of mine since I was 18. Recently I bought an inverter TIG welder to use for my automotive projects. I have just used the TIG to weld up a new dump pipe and some mild steel intercooler pipe for my new turbo setup. I'm pretty happy with it considering it was my first effort. I find TIG welding very enjoyable and have already picked up some good tips from searching these forums. Welding steel was fairly straight forward and after reading some tips on here and looking at education section of the Miller site I was able to do it well enough to make the dump pipe etc. However only the 'hot' side (turbo outlet) of the intercooler pipe is made from 2.5" mild steel tube. The intake side is made from 3" aluminium tube with each section joined with silicon joiners and bolt clamps. I want to weld all of these sections together to make it look a bit prettier. I've tried welding on some scrap pipe but obviously I'm doing something wrong. The electrode burnt back into the cup pretty much straight away and the arc was all over the place. I was able to join the metal but the weld was very wide and ugly and looked like it was sitting on top of the pipe. The pipe is 1.6mm thick (1/16)....we use the metric system lol. I had the machine hooked up to the foot pedal, no pulse, freq was at 100hz, 1/16 thoirated tungsten ground to a point, 1/16 filler wire (4043 I think), pure argon at 15L/min, penetration/cleaning set to 50% and I cleaned all the joins with a stainless steel brush prior to welding.Can someone tell me where I'm going wrong or what the correct machine settings should be? thanks!
Reply:Hello and welcome.If you are just learning to tig steel, Tiging alum will be quite dificult and very different from steel. Trying to learn alum tig on something that thin will compound your difficulties. Do you have your machine set to AC? You really need to be in AC to tig alum. I'd probably go with 3/32 tungsen myself to keep the tungsen from melting as fast, but my tig calculator suggests 1/16". You are using 100% argon not mig mix correct? What is your flow rate?Good luck.
Reply:yep the machine is on AC. It's pure argon gas at 15 litres a minute.
Reply:How many amps? My calculator shows between 60-90 amps for 1/16".
Reply:Way too many amps for 1/16" tungsten. Go with something bigger. If you turn the cleaning down to 35% +, it will be easier on your tungsten and put more heat into the plate.How thick is the aluminum and how many amps were you running? 1 amp for .001" plate or 39 amps for one mm is the rule of thumb.100 hz is a good place to start. Forget the pulse until you learn to weld better.PICS?DavidReal world weldin. When I grow up I want to be a tig weldor.
Reply:sphell,I'm going to assume that by "burning back" you mean melting back. Burning implies oxidation of the electrode, possibly caused by inadequate to no shielding gas coverage or not using pure argon (let's ignore argon/helium mixes for now).Melting back would imply that you are trying to run far too much current through the size of electrode electrode that you are using. In DC welding about 30% of the heat from the arc is focused on the tungsten electrode while balanced (50% cleaning) AC welding will focus 50% of the heat on the tungsten. Because of this the electrode will see considerably more heating when welding AC than DC at a given amperage.I would suggest that you change to a slightly larger electrode such as a 3/32" (2.4 mm). Thoriated tungsten is fine just grind it to a point then put a small flat on the end. One of the main reasons that using thoriated tungsten on inverters works so well is that with an inverter you can throw out the balance of the AC wave form. When welding on properly cleaned aluminum, you do not need 50% DCEP. I would set the machine to 30-40% DCEP (30-40% cleaning). This will focus less heat on the tungsten which, combined with the larger tungsten size, should pretty well eliminate the tungsten melting problem.The 100 Hz frequency setting seems fine, but my personal preference is to run 120 Hz minimum, usually I run at about 200 Hz.By the way, what amperage are you set at? I didn't see it mentioned in your post.Edit: It seems other people posted while I was writing... that happens alot.Visit Tensaiteki.com
Reply:Thanks for the help guys, I'll try a larger tungsten and turn the amps down a bit as well as adjust the cleaning down. I had the amps set a bit too high I think. They were up around 90A max, although I was using the foot pedal to adjust the current while I was welding. I'll try some of your suggestions and see how I go, thanks
Reply:Let me first say welcome and you have an AWESOME city. This is coming from a guy that hates cities of all sorts. Melbourne is a place I would move in a heartbeat, again coming from a country boy that likes the open spaces. I went there to GM HOLDENS 2 summers ago and aside from the plane trip 28 hours one way we had a great time and still I rave about how nice, neat and clean your city was. I probably only got to see a small portion of everything there is to see, but it was still great. Even got a speeding ticket from one of your cops; never did pay it so I might not be welcome back anytime soon. LOL.practice with your new machine and take your time and it will come to you as natural as walking once you get it down.Best Times with 434 Naturally Aspirated Vette60 - 1.261/8 - 6.37@ 107.25 MPH 1/4 - 10.08 & 134.9MPH1/4 - 9.60@144MPH
Reply:FWIW: I taught myself, before the internet. I have a x-former so some things may be different.The electrode burning back into the cup, someone else will have to figure that out. You said you're using pure argon, that's all I know. Can you hear gas flow when you touch the pedal? Probably, since you can weld steel.You said 15 liters a minute. We use 15cfh, you'll have to convert that. If it works on mild steel, I think you're ok. I don't change the flow for one or the other.DSW: Tiging alum will be quite dificult and very different from steel. Trying to learn alum tig on something that thin will compound your difficulties.Learn how to weld alum on 1/8". It will teach you the differences (steel/alum) without so much pain. I used a 3/32" tungsten. I also highly recommend 3/32" filler for starting. If you choose 1/16" filler, keep your torch angle steep or the filler will melt before it gets to the puddle. You used a stainless brush that's NEVER been used on anything but alum, right?Good luck, once ya got it there's an underlying satisfaction few can understand. 9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:15 Lpm = about 30 CFHEd 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:If Broccoli1 is right, you're wasting argon x2. If someone else is buying it you don't care. Well, wait a minute, that could introduce turbulence. I dunno. Last edited by Craig in Denver; 06-24-2008 at 12:52 AM.9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:Originally Posted by DSWHow many amps? My calculator shows between 60-90 amps for 1/16". |
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发表于 2021-8-31 23:57:35