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cegerer 11-26-2002 03:01 AM

Identifying Titanium
 
Is there a quick field test to identify titanium parts? I'm familiar with the unique color, are there any other clues? These parts are attached to other things so I can't weigh them. Thanks. -- Curt

deltajetfixer 11-26-2002 03:48 AM

When touched with a high-speed grinder, titanium will emit a shower of WHITE sparks.

RoninLB 11-26-2002 04:53 AM

Curt... no expert here..but to my understanding titan. is not a metal.. so maybe a ohm test will work/don't know. I believe it is made from silicone, like beach sand, and whacked with a great amt of electricity in a large plant, which makes it expensive.. Science News did an article a short time ago about a new process that is being experimented with now. will make it cheaper, much cheaper ...............Ron

GeorgeK 11-26-2002 05:01 AM

Titanium is a metal, one of the most common particle in our earth. What makes it costly is the separation/purification from other elements to which it is mixed.
A clue would be the complete absence of oxydation on the parts.
You have to give us some info her. Titanium rods?? What have you found? ;) GeorgeK

JWest 11-26-2002 05:39 AM

I asked the metalurgist in our department here at Lockheed.

Titainium is non-magnetic, so you could narrow it down to probably an aluminum alloy, stainless steel, or titainium if a magnet won't stick.

An aluminum alloy will be softer, so if you can scratch the surface with a hard knife you could narrow down to stainless steel or titainium.

From there it is very dificult without actually destroying the part.

cstreit 11-26-2002 05:51 AM

Oh it's much easier to tell.

Buy the part. If you start crying when you see your next bank statement, the part is titanium. :D

cegerer 11-26-2002 06:44 AM

OK, thanks for the tips.

<i>"What have you found? ;) "</i>

Hehehehee ... well, I've just been carefully studying the Porsche TAG-Turbo block I bought a while back. Looks like titanium head studs, among several other parts. It's really quite interesting, with lots of design elements that leave me completely baffled! Very complex piece of equipment. There's even a little bit of a 'do-it-yourself' flavor to it - not totally unlike fabricating something out in your garage!! -- Curt

RoninLB 11-26-2002 06:50 AM

Quote:

Originally posted by RoninLB
Curt... no expert here..but to my understanding titan. is not a metal.. so maybe a ohm test will work/don't know. Science News did an article a short time ago about a new process that is being experimented with now. will make it cheaper, much cheaper ...............Ron
found the info that led me to scramble titanium with the "earth's crust" in Sept 2000

Now, a novel method for producing titanium could make it more competitive with stainless steel, researchers claim. The cheapest form of titanium today costs at least several times as much as stainless steel. The new process could drop its price to one-third the current cost. Titanium's boutique status stems from its production challenges, not its availability. Titanium dioxide, familiar as white pigment in paints, is abundant in Earth's crust. Yet wrenching titanium from titanium dioxide has traditionally required a difficult, time-consuming chemical process, that also suffers from the disadvantage of using and producing corrosive and volatile substances.

Until now, however, electrochemical production of titanium hasn't offered much benefit over the strictly chemical method. In the new approach, solid pellets of titanium dioxide are fed directly into liquid calcium chloride. Then, an electrical current separates the oxygen from the pellets, leaving behind solid titanium metal. "I think it looks extremely promising and potentially could result in a significant reduction in the price," comments Harvey M. Flower of the Imperial College of Science, Technology and Medicine in London. "And that would dramatically affect the potential market for titanium."

One of the largest potential uses is in car manufacture, notes George Zheng Chen, a coauthor of the report and a materials chemist at Cambridge. Replacing steel car parts with titanium would lower a vehicle's weight, reducing both fuel use and emissions, he says.





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island911 11-26-2002 07:23 AM

Another quick test (nondestructive) is touch.

Ti's super low thermal conductivity means it won't sap all the heat out of your hand.
Though this only works in places like Curts' garage in the fall and winter months . . . you Californians are out of luck. ;)

Ron -- thanks for finding /posting that piece.

Pors911E 11-26-2002 08:48 AM

Head studs? Seems like a very unusual application for Ti. Ti head studs would have to be at least twice the dia. of steel studs to be capable of exerting the same clamping load. Ti also loses strength very rapidly as temperatures increase. Maybe they have some Ti in them as an alloying element? Thats far more common for fasteners.


Steve
Portland, OR
1971 911E

nostatic 11-26-2002 09:01 AM

hmmm...I didn't think it was the production of the raw alloys that was the main contributor to high price, but rather the costs of fabrication. While CP (commercially pure) Ti isn't too bad, the stronger 3/2.5 and 6/4 alloys are a b!tch to work with...chew up machining equipment, pain in the arse to weld, etc. Steel is soooo much easier to deal with...

For a lot of applications Ti is *not* the best choice...although it will get you oohhhs and ahhhs from the gawkers. Especially if it is anodized purple or green. :)

btw, you have to be careful with Ti bolts. If you are threading into a different metal you get an electrochemical reaction that fuses the two metals. Using Ti-prep (essentially ground up copper paste) instead of grease will help prevent this.

htbetz 11-26-2002 09:12 AM

Titanium in not magnetic.

Pors911E 11-26-2002 09:14 AM

Dr.St, you couldn't be more right. commercial grade Ti, is roughly 100 x more expensive (per lb.) than carbon steel. Welding must always be done with a tig process, in a low oxygen environment, and must almost always be done by hand. Additionally, Ti cannot be extruded and formed the way steel can as it oxidizes, crystalizes and breaks in the presence of O2 as it reaches working temperature. Ti has a great strength to weight ratio, but is a pain in the ass.

Steve
Portland, OR
1971 911E

island911 11-26-2002 09:30 AM

Quote:

Originally posted by Pors911E
. . . Ti also loses strength very rapidly as temperatures increase. . . .
compared to what? . . .ceramics?

cegerer 11-26-2002 09:47 AM

The head studs have a 'titanium appearance'. I'll have to look it over again tonight with some of the info gathered here. -- Curt

Leland Pate 11-26-2002 09:51 AM

All of the titanium aircraft engine parts i've seen have a much more "grayish" appearance than normal SS.

Pors911E 11-26-2002 10:01 AM

Island 911,

What I meant was relative to steel. Steel doesn't lose any appreciable amount of strength until temps climb above 600F, whereas Ti begins to lose strength around 100F. At operating temp (200F), Ti strength would be at roughly 85%.

Steve
Portland, OR
1971 911E

cstreit 11-26-2002 10:09 AM

Does the Ti strength cross the Steel strength curve at a certain temperature?

island911 11-26-2002 10:26 AM

Quote:

Originally posted by Pors911E
Island 911,

What I meant was relative to steel. Steel doesn't lose any appreciable amount of strength until temps climb above 600F, whereas Ti begins to lose strength around 100F. At operating temp (200F), Ti strength would be at roughly 85%.

Steve
Portland, OR
1971 911E

A bit misleading, don't ya think?
Or is "Ti" a brand of pasta noodle? . . .Boil at 212°F until softened.

To simplify; as Leland point out "aircraft engine parts" . . for that matter aircraft. If you want high temerature strength Ti is the choice.

Superman 11-26-2002 10:40 AM

Most of the Ti I have seen is dull grey, though it can be a shiny silver color. It is not magnetic, unless iron is in it. According to my understanding, it virtually refuses to conduct heat. According to the folks I spoke with at Boeing, you can place high heat at one side of a thin sheet, and the other side will remain remarkably cool.


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