Welding Titanium and Titanium Exhausts

[Lyn Labahn UW-Madison]

Gentlemen,

Assuming that I can find some properly sized tubing this year, I would like to make our header out of Titanium. Can you achieve good welds by assuring the proper flow out of the TIG torch, and purging the inside with Argon? Or is it necessary to build some kind of box around the part have a completely inert atmosphere surrounding it?

If anyone here has made an exhaust, did you make your own collector? If you had it made, who did it?

2002/2003 Team Leader
Best overall average finish of the new millenium http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Lyn Labahn UW-Madison]

Gentlemen,

Assuming that I can find some properly sized tubing this year, I would like to make our header out of Titanium. Can you achieve good welds by assuring the proper flow out of the TIG torch, and purging the inside with Argon? Or is it necessary to build some kind of box around the part have a completely inert atmosphere surrounding it?

If anyone here has made an exhaust, did you make your own collector? If you had it made, who did it?

2002/2003 Team Leader
Best overall average finish of the new millenium http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Charlie]

Personally, we haven't done it, but here's an article.

http://www.burnsstainless.com/TechArticles/Titanium_article/titanium_article.html

-Charlie Ping
Auburn University FSAE (http://eng.auburn.edu/organizations/SAE/AUFSAE)
5th Overall Detroit 2003
? Overall Aussie 2003. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[formula_geek]

Lyn-

In regards to your question about a collector. We have built our own header of stainless for the past two years using material from Burns Stainless. The first year we built our own collector. It was VERY labor-intensive and the finished product was rather rough on the inside, even though we back purged with argon. This year we bit the bullet and bought Burns' collector. It cost several hundred dollars, but was worth it from a time and quality standpoint.

Hoping to move to Ti as well...

Travis Slagle
Kettering University FSAE

[PSU Racing]

You can achieve good welds with a TIG torch and a purge line. We have been doing it for 3 years now.

Here is what you want to do. Turn the post flow rate up to about 10-12 seconds. Then purge the tube. Tap the TIG pedal and purge the weld area for about 5 seconds prior to welding. Then weld it.

Other pointers:
Ti doesn't flow as nice as steel and you have to be quick. To much heat and it will just become very brittle.

[Disco]

We're using a WR450F Yamaha motor this year that comes standard with a titanium exhaust. We wanted to shorten up the exhaust so we could push the engine closer to the driver. Had a word to our welder about doing it, and he wasn't too sure. He figured he'd give it a go TIGing it and if it worked, he saved us money. That was about three months ago and we haven't found a problem yet.

[Dominic Venieri]

We've used a Burns collector the past 2 years. Saves a lot of time and aggrivation. As for welding the Ti, we made a Ti muff can last year. Our welder at the time was able to TIG it just fine w/o having to back purge it and the welds came out as they should - a shiny silver color - with good penetration. It was .030" rolled Ti sheet. Of course the muffler isn't under any real stress, so the integrity of the welds never came into question.

For better advice, read that Burns article (and I think Carroll's book has some stuff on welding Ti as well?)

www.formularpi.com (http://www.formularpi.com)
2003 Formula Student Runner-Up

[GIJoeCam]

We used Ti for our header for the first time in '02 using the purge technique described. A seperate purge hose to flood the inside, and a lot of purge before and after the weld. They held up great and are still running now.

-Joe

2002 LTU FSAE Co-Leader
2002 LTU FSAE Brake System Engineer

[scooter2131]

So I see that the purge technique works for welding Ti in our shops. Can anyone post pics of their setup for purging the weld area for TIG welding Ti? Where do you guys get your titanium tube for header construction? I found one company SPC (http://www.cartech.com/epg_cspc/weldedtube.html) but they don't make 1.375 OD tube. Titanium 2-1 PM collectors would be nice too. Any info would be great, I haven't found much googling.

Anyone from Lawrence Tech have any insight on how they constructed their Ti header they mentioned in their 2002 paper?

Thanks

[-]

I had researched making a set of Ti headers last year and after looking high and low for the appropriate tubing sizes (diameters and wall thickness) alloy, and then for someone to bend the stuff I came to the conclusion that my time was much better spent ordering pre-bent 180 degree U-bends and collectors and making my own out of thin-wall 304 SS. With two phone calls I had all of my SS tubing ordered and in the mail that day and a header was welded up by the end of the week.

Of the suppliers that had the sizes and alloy of Ti tubing that I wanted, it was next to impossible to get them to sell me some since most of the material was going for government contractors and was already accounted for. Also I only found two benders that were willing to take on the job of bending small diameter thin-wall Ti tubes and they wanted roughly 3 times the price for what similar SS pre-bent sections cost.

To anyone who can find the right size tubing and afford to bend it (or beg on your knees to get it done for free) I would love to see the final product and know how much trouble and $$$ it took to get the job done

If I were to build a header again I would either go the same route of thin-wall SS (0.049 I think), or use even thinner mild steel headers and have them ceramic coated to give them a chance of surviving the heat of the exhaust.

As for making your own collectors, they are easy to make, you just need to plan out what you want to do and have a good welder with a steady hand to put them together. This saves a ton of money for other things. For welding the SS headers, if you go that route, try to back purge the headers by tacking them all up first, putting tape around the joints you aren't welding, capping off one end and filling in argon from the other side. This leaves the inside of the weld looking just as smooth as on the outside.

Good luck and post any pictures of the final product

[scooter2131]

I've tried googling like mad, I'm still not coming up with any suppliers for 1 3/8 or 1 5/8 titanium U-bends or collectors. Can anyone give me some insight? Guys from Lawrence Tech, where did you get the titanium for your headers?

[Buckingham]

When we investigated Ti exhaust, we had a plan to get each primary tube CNC bent as a single piece (by someone who had done it before).

Even if you can't find a CNC bender, you might have better luck having someone bend you some custom U-bends or angle bends to make your own collecters.