Titainium welding

[Tom K]

I trying to build a Titainium header for the Formula SAE race car at my school. From what I understand I need an argon chamber. I thinking about building one from a sandblast cabinet. Does anyone have any suggestions? I have a miller tig welder. Do I need to use special electrodes?

thanks,
Tom K.

[Guest]

Re: Titainium welding

Originally posted by Tom K
I trying to build a Titainium header for the Formula SAE race car at my school. From what I understand I need an argon chamber. I thinking about building one from a sandblast cabinet. Does anyone have any suggestions? I have a miller tig welder. Do I need to use special electrodes?

thanks,
Tom K.

Yes, you will need titanium welding rod to match the alloy you are welding. The electrodes I use are tri-mix tungsten, but 2% thoriated will do, also.

You can build a purge chamber, from a sand blast cabinet. They use a whole lot of argon. I would suggest a six pack of Argon, unless you have plumbed in argon.

Here is a picture of a purge chamber I built for my company.

All that said, I would add that it is possible to weld titanium with out the chamber, in the atmosphere, you just need to master the technique.

[Tom K]

hey, thanks a lot for the picture. That was exactly what I was thinking about. Do you really think I'll need six tanks of Argon? What is welding Titainium like? I have been tig welding Steel and Aluminum for a few years now. This header I'm building is a one time thing and building a chamber might not be worth it for us. Can I just turn up the Argon flow?

thanks again
Tom K.

[Bob]

Here is a link from a forum post a while back

http://home.hiwaay.net/~langford/sportair/

Lots of excellant (but large) picture files, be patient it is quite interesting.
I will attempt to add one pix from that site. It shows a "micro-purge-chamber" using aluminum foil. I guess you would put a tee in the gas line, add a second hose with a manual valve, and possibly turn up the total flow thru the gun and to the purge container.

You might experiment with something like this.

Bob

[Guest]

Originally posted by Tom K
hey, thanks a lot for the picture. That was exactly what I was thinking about. Do you really think I'll need six tanks of Argon? What is welding Titainium like? I have been tig welding Steel and Aluminum for a few years now. This header I'm building is a one time thing and building a chamber might not be worth it for us. Can I just turn up the Argon flow?

thanks again
Tom K.

Turning up the flow will result in turbulance, sucking in air...not a good thing to do.

As Bob mentioned, for a one time thing, you could construct a bench model of the purge chamber.....use your imagination for that....like plastic plates taped together works...cut out glove holes and tape your gloves on....it just has to maintain an argon for the time that the part is hot. It has to be big enough to allow you to move the part around and get both hands in it. You can use a hood with an auto-darkening lens. Put a piece of scrap ti in there to test your purge before you weld.

If you weld ti out in the atmosphere, it must not turn blue, or have grey cobwebs on it....it can break like glass. A little straw coloration is acceptable, however, just not preferred. Weld in a backhand motion, keeping the torch pointed on the puddle, and move away from you..gas pressure is critical...not too much. Feed the rod in the side or the back of the puddle, and be careful not to touch anywhere other than the molten puddle with the rod, because the rod will stick. Very frustrating. The ti weld should look like chrome when you're done, with no discoloration.

Practice a lot first, and you should be ok.

[Tom K]

Hey, thanks again. As I mentioned before, I'm building an exhaust header. I'm thinking I might try taping the tubes together and filling the header with Argon. Then welding on the outside. I would clean all the glue from the tape first. I got the idea from that other guy using aluminum foil to shield the other side of the weld. Does this make any sense, or does anyone think it will work? Of course, I will try this on scrap tube first.

thanks again,
Tom K.

[Bob]

Tom K,

You said: "Of course, I will try this on scrap tube first."

Sounds like you have the idea to experiment to find out what will work for this one time project.

You can probably buy a lot of aluminum foil for the price of six tanks of argon. Since this is basically tubing, I also thought of closing the ends and filling the interior with purge gas. Perhaps feeding in the purge gas to a specific weld joint in a length of copper tube and packing the ends with loose foil wads.

You don't need a perfect seal anywhere, so I would aviod tape, rubber bands, anything that won't take the heat.

Might cut some aluminum flashing to the radius of the pipes to help build the wells for the argon.

Rocky D is probably right about too much gas creating turbluance. Maybe normal flow, but use it first to fill the localized well, then for the torch.

Disclaimer: I have never ever welded ti, but this seemed like an approach that might be made to work for a one time project. Hope it helps.

Bob

[Guest]

Originally posted by Tom K
Hey, thanks again. As I mentioned before, I'm building an exhaust header. I'm thinking I might try taping the tubes together and filling the header with Argon. Then welding on the outside. I would clean all the glue from the tape first. I got the idea from that other guy using aluminum foil to shield the other side of the weld. Does this make any sense, or does anyone think it will work? Of course, I will try this on scrap tube first.

thanks again,
Tom K.

You can tack the the tubes in the atmosphere, and they can be grey on the inside, but purge each tack on the out side, then after you have it all tacked up, fill it with argon, about 40 of 50 CFH and as you weld it, you will purge the tacks on the inside.

Another trick in welding ti is to run a sealer pass, on all your joints to make sure you have all the gaps and places where air can get in are closed, let purge for a minute, then reweld it hotter for penetration. It is important you have a good seal all around when welding, or you could suck in air. The inside should look like chrome, just like the out side.

Of all the metals I weld, I like Titanium the best.

[Dan]

Rocky D

I ve never had the opportunity to weld Titanium. Could you post us (me) some pictures of some welds so that we (I) can see how it looks? Just curious.

Dan

[Guest]

Originally posted by Dan
Rocky D

I ve never had the opportunity to weld Titanium. Could you post us (me) some pictures of some welds so that we (I) can see how it looks? Just curious.

Dan

Sure, but it's going to be after my vacation...next week...I'd love to see what you could do with it.

[Tom K]

thanks

Hey guys, thanks a lot for all your help. You have answered all the questions I have at the moment. I'm not going to be able to try welding Titainium for another week or so, so I'm sure I'll have another set of questions then. Just for show, here is a picture of last years race car. The new one begins construction in a few weeks for competition this summer! Our welder is on the left and our new mill is in the back. I welded a lot of the car myself and did a lot of the last minute machining. This year I'll probably be welding the whole thing.

thanks again
Tom K.

[Tom K]

picture

Here is the picture, it didn't work the first time.

[Mike Sherman]

Nice car Tom. On Titanium welding purge the pipe and use a trailing cup. It welds very similar to stainless steel but is very sensitive to atmospheric exposure. This should not be a difficult job.

[mikeb]

Ti welding

A while back I was thinking about making titanium anode baskets and I asked a bunch of questions about Ti welding on this site and got some good replies.

[Bob]

Tom,

Another off the wall idea from Bob.

Sounds like "argon rich" around the weld is not near enough. What is needed is more like pure argon, as in oxygen free. Not sure the ad hoc foil will get there.

I have heard of "pre" and "post" flow; assume this means gas starts before the weld and keep flowing after. If your machine does not do this you could probably try an experiment. You can probably disconnet the gas tube from the torch cable just inside the welder. Run a seperate length of tube (maybe 25' plastic from Home Depot) from the torch cable launch directly to the regulator output. This bypasses the on/off gas value in the machine.
Kink, un-kink the hose to purge and set the flow rate. When you run the experimental welds, the flow will be on well before the arc. Since you want to keep the protection on the metal while it initially cools, the flow will run well after the weld while you hold the torchs steady. A little wasteful of argon for the experiment, but it is an experiment. If it works you might rig a better valve, or even put some non-standard wiring on the valve inside the machine for external contol (that could void a warranty, if you have one ..? !!)

Free advice is worth the price.
Bob