TIG welding Ti. Questions on setup and the general process

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I've done quite a bit of aluminum, and some steel. My aluminum welding is actually a little bit nicer then my steel. I'm looking to try out some Ti and was wondering what I need setup wise. I've heard that the welds need to be shielded even after the puddle has dried. How do you accomplish that? What type of tungsten? Pure, 2%? What filler rod? Argon, Helium, or a mix?Last edited by BillyGoat; 06-17-2006 at 04:45 PM.
Reply:I've heard it welds just like stainless steel.  Use a good back purge and long post flow.
Reply:You will need what is called a "trailing cup" to shield the still-cooling weld pool as your torch travels.
Reply:set your machine the same as mild steel or stainless steel, use a 2% thoriated tungsten, mandatory argon back up on the underside of the weld. You can use 1 of these large diameter gas saver tig set up at the bottom of this link, with a slow travel speed you can weld 3 to 4 inch's with good gas coverage, Ideally you are looking for a silver color on both sides of your weld, gold is acceptable as well, no blues or purpleshttp://www.ckworldwide.com/gas_saver.htm
Reply:So with the large diameter cup I get coverage of 3-4 inchs...What about after that? How long do the welds need to be covered before its OK to expose them to the air? I'm assuming its a heat issue with the weld still being semi porous when its hot.
Reply:no not at all...it welds just like stainlessyou may want to use a gas lenz..the bigger one...with 3/32 red end tungestonpost purge about 5 secondsstraight argon...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:with that cup or a trailing shield your weld only needs to be covered with the argon gas for just a short period after the puddle has solidified, just remember to decrease your travel speed while welding, Ideally you want to weld Tianium in a chamber, either a home made unit, or one like is sold on that CK link I posted . Also match your filler to the base material, example if you are welding commercially pure Ti, use a commercially pure rod ( ams4951), if you are welding a alloyed titanium such as 6al4v use a 6al4v rod ( ams4956, or ams4954)
Reply:Hi Billy Goat!Titanium welding is not at all difficult to perform. however because of the nature of the metal being of a "reactive" type, there are certain precautions and set up of equipment one has to take into consideration when welding Ti...Here are some things to consider when GTA welding commercially pure Ti like grade #2: 1. Make sure everything is CLEAN! What I mean by that is, to make sure the base metal is clean, the wire brush is a NEW Stainless steel one that has NEVER been used on anything else... Make sure if you handle the wire or the material ,that you have clean gloves on that will not transfer any residue on to the filler metal or the base metal... VERY IMPORTANT TO BE CLEAN!!! 2a.If you're going to TIG weld (GTAW) Ti, you need to have pre and post weld shielding settings on your GTAW power source so that your gas shielding is on prior to and way after you finish your arc time on and off (welding time ignition until welding shut off )... I remember at Titanium Fabricators, we used a 5 to 10 second pre-flow time and a 40 second post-flow time setting for most of the welding on Ti...2b. You're going to need more than gas hose and flow meter for your torch shielding gas, your trailing shield gas and your backpurging shielding gas used on pipe and the backside of any and I mean any joint configuration but, even more important will be the quality or grade of the argon gas... In other words, a shielding gas with an oxygen content of more than 10 parts per million will be inadequate if you wnat to achieve optimal, x-ray quality results.So choose the quality of argon gas wisely! If you're going to weld alot of Ti, then I would suggest to use a liquid argon tank with one or two "Y" connections for all three of your gas shielding sources... In other words, you're going to go thru alot of shielding gas and you're going to need more than one outlet from the source in order to supply your primary, secondary or "Trailing" and Backing shielding gas supplies...  3. A water cooled torch is recommended but then again that all depends on the thickness of material you're welding and at what current you choose...The torch should have a gas lens collet body, the widest possible ceramic cup for better gas coverage... 2% thoriated tungsten will work fine but, if you have some issues regarding the potential adverse effects with thoriated tungsten, then use Ceriated tungsten... You must have some sort of "Trailing shield" configuration attached to your torch so that the weld deposited behind the weld puddle is still being covered with what is called a "Trailing shield", so that the weld is protected from atmospheric contamination as the already deposited weld solidifies and cools down... The gas shielding does'nt stop there as the backside of the joint where the weld is being deposited must also be properly covered with argon shielding also in order to avoid weld root atmospheric contamination also! So prepare to cover all the bases so to speak because, Titanium is very reactive to the amount of oxygen in the air. I'll post a website or two that'll give you an idea of how to construct an appropriate "Trailing shield" to attach to your TIG torch...Stainless steel tubing with holes drilled into it can be used as an effective backing shield on either groove or fillet welds so long as there is a complete blanket of coverage throughout the length of the joint prior to welding or at least to where the weld will stop and at least 4 inches beyond that so that you can reposition the backing shield in order to continue welding to the end point of the joint. Also make sure that you have plenty of masking tape!!! 4. Set your machine to DC straight polarity or Electrode Negative for Tig (GTAW)... Parameters depend on thickness, travel speed and position... Here are some of the websites that will give you all of the necessary info needed in order to set yourself up for welding Ti but ,none of these sites will teach you how to weld Ti so I'll include on that will offer one and two day seminars on how to weld Ti in San Diego, CA:http://www.tifab.com/subpages/index.htm  Lots of good info here!http://www.titanium.org/Category.cfm?CategoryID=9 seminar info found here!http://www.azom.com/details.asp?ArticleID=1245http://www.huntingdonfusion.com/down...lamp%20ATS.pdfhttp://www.huntingdonfusion.com/HFT/...showpage&pid=9http://www.timet.com/fab-p30.htm  check out links on bottom of page also!http://www.twi.co.uk/j32k/protected/band_3/jk24.htmlhttp://www.designnews.com/article/CA603693.htmlHere's an oldie but a goodie on USN research submarines: http://wwwnavsource.org/archives/08/08354.htmThis school is focused on bicycle building and frame welding:http://www.bikeschool.com/frame.htmHere's some technical info provided by the USN's "Mantech" center regarding dew point levels in the shielding gas:http://wwwnsrp.org/st2005/Product%20...tions/Tran.pdf here's an article about welding Titanium for war by Weldingdesign&Fabrication:http://www.weldingdesign.com/323/Wor...e/False/11146/here's a Technical Data Sheet from Allegheny Ludlum on Ti:http://www.alleghenytechnologies.com...m%20alloys.pdfCheck this one that's a bit off topic but, check it out anyway:http://ilc.final.gov/pdfs/jlab/12Kelly.pdfLincoln Electric has an advanced Motorsports welding seminar which covers Ti welding fundamentals among others and at a decent price range so, here's the website: http://www.lincolnelectric.com/focus...ool/school.aspHere's some technical information regarding the microstructure of Ti welds:http://www.struers.com/resources/ele...ure%203_EN.pdfHere's one more:http://www.specgasreport.com/archive/oxyargon601.htmHere are some more "Trailing shield "cups" of different configuration available from the TIG Depot:http://www.tigdepot.com/products/p5.htmlHere's an ideal dual flowmeter for Ti welding:http://www.tigdepot.com/products/p6.htmlHere's an overall good .pdf file on TIG welding (GTAW) in general which includes Ti GTA welding from Miller Electric:http://www.millerwelds.com/education...Book_Chpt6.pdfWell, this concludes what I can offer you as of today so, when I find more articles and info regarding Ti TIG welding, (GTAW) I'll post it for everyone!Respectfully,SSBN27Last edited by SSBN727; 06-18-2006 at 01:37 AM."Run Silent...  Run Deep!!!
Reply:What ssbn727 just said , illustrates what i had said earlier, that THE PROs @Mare Island did with titanium , they solved their problems by welding the titanium in a "tent" . An "enclosure with argon purging ". that solved a lot of problems with one single approach. i think this is actually the easiest way out . face it , their is no magic(EASY) bullet. you have to do it the way (some way ) that works. anything less is just fooling yourself .
Reply:Wow, awesome information and help so far. Thanks alot guys. ssbn727 those links will be immensly helpful. I'm going to go over each one of them and perhaps in a week or so I can post some pictures of my work in progress. I appreciate all the help.
Reply:I am the terror of Mare Island.  Them's my jack rabbit hunting grounds.
Reply:Hi All! I wanted to repost the website regarding the Ti welding of research submarines built for the USN because on my first post, I left out a period between www and navsource so here is the correct link and I apologize for any inconvenience:http://www.navsource.org/archives/08/08354.htmRespectfully,SSBN727"Run Silent...  Run Deep!!!
Reply:Hi,I've done a good amount of Ti. and elderthewelder and Roy are putting you right on target for a successful result. You can't possibly get the material or filler rod too clean. i made a small fixture for doing small jobs to eliminate a purge chamber.It is no more than a pair of 1/4" SS tubes that have .040 holes stager drilled every 3/8". I then plug one end of each tube and arrange them on a copper plate so the holes are NOT exactly across from each other but again staggered I have a Harris flow meter with dual adjustable flow and I use a bit less (15CF) on the tubes that are connected by a small slip on hose with a Y fitting. If you don't have a dual flow meter use one of those neat little regulator Y type splitters. This will do an fine job for the underside purge on flat work and also round stock ie. engine valves by using the fixture to elevate the work above the tubes and the copper plate allows for you to place the tubes in whatever  configuration required to allow for good shield gas coverage. I try as both Elder and Roy stated go slow with about a 15 sec. pre flow and 45 sec. post flow keep the input low as possible try ceriated or 2% Lathanated ground to a point and trunicated. Use a very large cup (1") or trailing cup and when you are ready to stop the weld release the current flow and stay parked over the end of your weld until the post flow stops You are looking for a straw like color to be on the finished weld, if it turns blue you have screwed the pooch and need to toss it. It's a slow and patient process much like the difference between magnesium to aluminum. The learning curve is a short one just remember to keep the heat down to a minimum
Reply:At my current workplace we have frequent & random Xrays performed on our work.Frequent as in every 2 - 3 weeks, or at the customers reqeust.What SSBN727 said is correct. Though I'd like to add a thing or two:Titanium has an extreme affinity to oxygen!We use a carbide burr inside, outside (2 cm both sides), bevel & root face.Removal of the oxide is important - depending the desired weld quaility, a wire brush maybe OK, but with us it's not accectable.All parts are thoroughly washed in acetone, including the filler wire.Joints should be welded as soon as possible after weld prep. and washing.Titaniums oxide layer forms quickly, and if you leave welding to the next day an oxide layer will have re-formed.
Reply:Something else we use at work is pneumatic valves on the flow metres. The gas is then turned on and off by switch which mounted on our work bench or work peice of where ever it's suitable to have it.Our welding machines don't have pre-flow, which sucks.A good aspect to using the pneumatic valves - if the power is cut to welding machine, the fuse blows, or there's a power cut, we still have gas flowing until the weld cools.And we actually had a power cut last month. I was welding titanium at the time, and I just kept the torch in place until it cooled, and then waited for the power to come back.Without those valves that weld would of been ruined.Obviously it's not something you must have to weld Ti, but it can be helpful.
Reply:Okay, so what would you guys recommend to mend Ti with Stainless Steel?  Also, what are some good resources for obtaining Ti?  Esp. pipe/tubing?ThermalArc 185MillerMatic 180 w/ AutosetVictor Cutskill Oxy/AcetyleneThermal Dynamics Cutmaster 38and spite!
Reply:Originally Posted by DirtyLittleSecretOkay, so what would you guys recommend to mend Ti with Stainless Steel?  Also, what are some good resources for obtaining Ti?  Esp. pipe/tubing?