tig welding info

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hiI'd like to know what happens if a person try to weld TIG without using the inert gas
Reply:Nuttin.  You won't get a weld.  Tungsten will toast its self.David Real world weldin.  When I grow up I want to be a tig weldor.
Reply:okand what about tig welding in vacuum?would it be possible to weld without using the inert gas?thanks
Reply:Originally Posted by bennettokand what about tig welding in vacuum?would it be possible to weld without using the inert gas?thanks
Reply:I can make vacuum but I haven't tig machine to try..
Reply:Originally Posted by bennettI can make vacuum but I haven't tig machine to try..
Reply:There would still be some air in a vacuum.HH 187Miller Bluestar1EAHP AlphaTig 200X
Reply:two issues with vacuum:1. nothing to ionize to help the arc jump from tungsten to metal (not sure that this makes much of a difference)2. gas helps move the heat from arc to metal (note use of Helium to improve heat transfer in Aluminum welding).  Probably makes some difference.Would it be possible to TIG weld in a vacuum? Probably, but it wouldn't be TIG (GTAW) by definition, since you are not relying on inert gas as a shield).Why, you going out into space?  Bet NASA has a special training program for their welders, and they will teach you the ropes...Tim
Reply:has NASA ever made a weld in space? oxygen is the problem and it's presence creates some problems both starting the arc and when trying to melt your base material. if you can get rid of that it is probably possible. sure shielding gas helps transfer the heat but is it critical to a sound weld? pretty sure that nobody will be able to give you an answer cause nobody has ever tried it. keep us posted...
Reply:No, you wouldn't be able to weld in a vacuum.  As was mentioned, there are no molecules to ionize.  It is possible to have electrons move in a vacuum through field emission, but they wouldn't emit light, I don't believe they'd generate any heat across the gap, and they wouldn't be an arc in the sense that we're accustomed to.  They have generated "sparks" at extreme voltages across extremely small gaps (.001mm or so), but they don't follow any sort of predictable path, and their nature isn't fully understood.   Most popular belief is that it's created by some sort of dust or surface contamination.
Reply:I emailed the question  to a welder and he sayed that it should be possible to weld in vacuum and generally titanium is welded in this wayis there someone who can try directly?
Reply:If titanium is welded in a vacuum, it has to be the laser or electron beam process.Now, it would be a good thing to put titanium in a vacuum chamber, pump it down, and then backfill with pure argon or helium.  That is how we welded our zirconium where I used to work. Mabye that is what your friend is thinking.Otherwise, we used to put our titanium in a big plastic bag and purge with pure argon with an outflow valve that was open.And yes, I agree, it is not possible to arc weld in a pure vacuum.  That is what is taught in every welding theory class.
Reply:Is this just a theoretical academic question, or do you have an intended application? I would think it not practical, if possible.
Reply:A TIG arc cannot exist in a vacuum with no inert gas supply because the arc requires ionized gas particles.A technique has been developed to TIG weld in space (vacuum) with a hollow electrode and inert gas supplied through the electrode, called hollow cathode arc (HCA).  (In TIG the electrode is negative and emits electron, so it is the cathode, whereas the work piece is positive and is called the anode.)  The following is an abstract from one paper on the subject of HCA taken from this link:  http://cat.inist.fr/?aModele=afficheN&cpsidt=14020109"A feasibility study has been conducted to determine whether a hollow cathode arc (HCA) can be used for a welding heat source in space, that is high vacuum and microgravity conditions. The HCA method enables the arc discharge to form under low pressure conditions by purging a small amount of gas through the centre of the hollow cathode. The characteristics of HCAs under low pressure conditions have been experimentally investigated, in particular the melting properties and voltage-current characteristics. Results show that the penetration profile and are characteristics of the HCA method are sensitive to process parameters such as gas flowrate, arc length, and inner diameter of the electrode, and that the penetration in HCA melting is extremely deep under the conditions of low gas flowrate and long arc length."
Reply:Is this just a theoretical academic question, or do you have an intended application?
Reply:Welding in a vacuum....... if it could be done (big if) it would have to be robotic, since flesh couldn't stand the vacuum for any reasonable amount of time. In a vacuum moisture/water boils off at 12"hg and air/oxygen still has a presence after 2 to 3 hours, enough to contaminate a weld. Just what I know from HVAC vacuum operations.Miller Thunderbolt 225Millermatic 130 XPLincoln HD 100 Forney C-5bt Arc welderPlasma Cutter Gianteach Cut40ACent Machinery Bandsaw Cent Machinery 16Speed Drill PressChicago Electric 130amp tig/90 ArcHobart 190 Mig spoolgun ready
Reply:The closest common example of an arc operating in a vacuum is the fluorescent light. A very high voltage is required and the electrons hitting the rare gas molecules cause ejection of short wave UV light which in turn hits the phosphors which adsorb it and then radiate visible light.
Reply:That statement is contradictory."electrons hitting the rare gas molecules"That's not a vacuum then.Actually, fluorescent lights have a low pressure, but contain mercury vapor.Electrons hitting the mercury molecules excite their electrons, which releases UV light (which is fluoresced as white light by the white powdery phosphors on the tube's inner surface)
Reply:Originally Posted by bennettI emailed the question  to a welder and he sayed that it should be possible to weld in vacuum and generally titanium is welded in this wayis there someone who can try directly?