How To Tell If It's Really Titanium

With the growing popularity of titanium, some disreputable merchandisers are passing off other materials as the more expensive metal. Popular Science looks at a surefire way to prove what that credit card/crowbar/ring is really made of. "Hold any genuine titanium metal object to a grinding wheel (even a little grindstone on a Dremel tool will do), and it gives off a shower of brilliant white sparks unlike any softer common metal. The sparks are tiny pieces of cut titanium--the friction of the grinder heats them till they burn white-hot. Hold a grindstone to the shackle of a "titanium" padlock from Master Lock, however, and you'll instead see the telltale fine, long, yellow sparks of high-carbon steel."

is there a better way?

[pwizard2 (920421)]

The method in TFA sounds like it would really scratch up whatever you're trying to test. Is there a way to run a test without damaging the object?

Density test

[Ostsol (960323)]

If the object in question is constructed from a single material, then a density test should work. Use water displacement and a scale to determine the volume and mass, respectively. From that you can calculate the density and compare the value to the actual density of titanium. Of course, this won't work if the object merely has titanium components and it cannot be disassembled. . .

Re:Density test

[g0dsp33d (849253)]

It still works for electronics though! (you'll prove something is dense)

Re:Density test

[g0dsp33d (849253)]

Its not too hard, you can try it from the comfort of your tub with a toaster.

Re:is there a better way?

[Dan East (318230)]

Yes, there is a better way, and your concern about damaging expensive objects - particularly jewelry - is quite justified. Simply send the object to one of my two testing centers (conveniently covering both hemispheres - one is located in Russia, the other in Africa) and we will send you a full report of the object's composition.

Dan East

Re:is there a better way?

[necro81 (917438)]

How much are you paying for that service? For $30,000-40,000, you can buy a handheld x-ray fluorescence analyzer [niton.com]. These things got started in testing for lead paint, and now get used to test and check for lots of things - including alloy composition verification. An XRF shines x-rays of a known energy at the test sample, then detects and analyzes the spectrum that is reflected back. Each element has a characteristic x-ray emission spectrum based on the energy of electrons dropping into lower shells. In 10-20 seconds, you can get a really good breakdown of the elements in the test sample.

Re:is there a better way?

[ByteSlicer (735276)]

A laser spectrometer [wikipedia.org] can do this for you. It will still create microscopic damage though.

Re:

[Ceriel Nosforit (682174)]

Useful trivia:
Steel is a blend of iron and carbon. Mostly iron, in all its incarnations, and iron is always magnetic.

High-carbon steel is very hard but a bit brittle, while steels with less carbon will usually deform before they crack. There is always a compromise between hardness and toughness.

Re:a magnet?

[Kazymyr (190114)]

...iron is always magnetic.

That is a big fallacy. There are some alloys in which iron is around 98-99% which are non-magnetic (think unusual alloying elements like niobium and rhenium).

Re:a magnet?

[budgenator (254554)]

Iron isn't always magnetic, when heated to or above it's normalization temperature it loses it's magnetic properties, you can hold a piece of steel suspended with an electrimagnet in a kiln and heat it, when it reaches it's normalization temp it will fall to the kiln floor.

Re:a magnet?

[Gordonjcp (186804)]

And in fact, some soldering iron thermostats use this property. When the iron is cold, a magnet pulls the contact closed. Once it heats above the Curie point, the magnet lets go and the contact breaks.

Re:a magnet?

[Lord Ender (156273)]

If it weren't for slashdot, I would never know amazingly pointless facts like this one. Thanks, slashdot.

Re:a magnet?

[Grishnakh (216268)]

Sorry, that's not my understanding of the metal's properties. I guess for digging around in the sand, you don't really need a fine edge, but nothing to my knowledge compares to the ability of steel (esp. high-carbon steel) to hold an edge. High-carbon steel is very brittle, which helps it to hold an extremely sharp edge; this is why Japanese samurai swords were forged to have one side harder than the other side, so the sharp side would be extremely hard, but the other side would be less hard and more strong (done by using clay on one side during quenching) so that the blade as a whole wouldn't break easily.

There's a reason no other knives are made of titanium, or anything besides steel for that matter.

Titanium is known to be a very strong metal. If you know anything about metallurgy and its terminology, strong and hard are different properties, and usually work against each other: a metal is usually strong, but not hard, or vice versa, not both. Steel can be made to be hard, but brittle, or strong (which is more flexible) but not very hard.

Anyone with a titanium ring knows that it's not a hard metal at all: it's easily scratched unless it has a protective coating (usually diamond). Sure, it might prevent a automatic pressure door on an undersea rig from locking you in, but it doesn't hold a sharp edge at all.

Re:

[budgenator (254554)]

Steel is actually an alloy containing predominately iron, usually has a good amount of precipitated Ferric Carbide crystals , ferric-Carbide in solution with the iron and often trace elements and occasionally minute amounts of pure carbon which is detrimental. The amount of carbide in solution and precipitated greatly controls the physical properties of the metal and is controlled by the heat treatments the steel is exposed to during manufacture.

Re:a magnet?

[funfail (970288)]

You've never tried to stick a magnet to a stainless steel fridge, have you?

That's because they mislead the customer by using titanium instead of steel in fridges.

Re:a magnet?

[the eric conspiracy (20178)]

Depends on the type of stainless. Austentitic is not ferromagnetic, while martensitic is.

Re:a magnet?

[LynnwoodRooster (966895)]

Nope. Get above 0.15% carbon or so and you lose almost all the magnetic properties of iron. It's one reason that loudspeakers are made with low carbon steel (usually 1006, 1008, or 1010 grade) since you get too much carbon and the flux no longer flows well, meaning you need a LOT more magnet and a higher grade magnet to get the same flux in the gap.

And yes, I am a loudspeaker engineer... ;)

MERRY CHRISTMAS!

Re:a magnet?

[cerberusss (660701)]

And yes, I am a loudspeaker engineer... ;)

MERRY CHRISTMAS!

Could you turn that down please? :P

Re:

[necro81 (917438)]

Most steels are magnetic to various degrees. However, when designing some stuff that would be used in an MRI suite, I did some research and found that some grades of stainless steel - specifically, 300-series [wikipedia.org] stainless steels (302, 304, 316, etc.) - are more or less nonmagnetic [physlink.com]. They can't be used inside the bore of the scanner, but that's mostly because it screws up the uniformity or the magnetic and RF fields necessary for imaging. This was a handy discovery for me, because sometimes aluminum and plast

Re:Safety first?

[smidget2k4 (847334)]

Gloves + rotating grinder = BAD. You don't want a glove to get caught in that, your hand goes with it. Better to be burned by some sparks than to lose a few fingers (at best).

Oh great...

[grassy_knoll (412409)]

Think the store will mind if I bring a dremel with grinding wheel to the store with me? For testing purposes of course...

Good news

[by Anonymous Coward]

Apparently my wife's jewelry was all genuine titanium!

Re:Good news

[niceone (992278)]

Lock up the dremel before you go to sleep tonight.

Or use a cutting torch

[$RANDOMLUSER (804576)]

It heats white hot almost instantly, and when you thumb the oxygen cutting lever, you get the most amazing shower of white sparks - like fireworks - very pretty!

He also runs periodictable.com

[Ed Pegg (613755)]

The author of this Popular Science article, Theo Gray, also recently relaunched http://www.periodictable.com/ [periodictable.com] Thousands of elemental pictures and videos are available there, all linked in with his Popular Science series.

Don't try this away from home

[dacarr (562277)]

One thing to keep in mind is that sales droids are probably not familiar with the wonderful world of minerology and/or science minded. They are sales people for a reason. They aren't the people who understand these concepts. (If anyone should understand the concept, it is you, the reader.) So as such, if you go and apply a dremel tool to, say, a platinum wedding ring you have in mind for your wife and, lo and behold, it's showering yellow sparks, the first thing through their mind is not going to be something to the effect of "aw dammit, I've been found out!", it's going to be more like "Holy f*ck! This f*cker just damaged my merchandise! POLICE!". You can't talk logic into them, and the police are more likely to side with the jeweler. Sure, you might be able to prove the jeweler wrong in a court of law and countersue for false advertising (and expose him as a fraud), but having to fart around with legal crap for months is, for one, not my idea of a good time.

This is very much a point where Hanlon's Razor can be applied.

Ow! Shit!

[schon (31600)]

Man, I just tried this with a new package of Energizer Tianium, and the spray burned a hole through my skin!

You can be sure I'll be returning these "titanium" batteries just as soon as I'm back from Emergency!

A few simple ones

[BlueParrot (965239)]

a: Titanium is not ferromagnetic, and hence it is not attracted by magnets as strongly as iron is ( the difference in force should be orders of magnitude ).
b: Titanium's density is 4.5g/cm^3 , iron is 7.8g/cm^3
c: Titanium is corrosion resistant to dillute sulfuric and hydrochloric acid, iron is not.

Re:A few simple ones

[florescent_beige (608235)]

It's hard to determine the density of something like a ring because even if you weight it you don't know its volume. But there is a way around that, weigh the item in air then in water and take the ratio of the weights. A jewelry store would be more open to that idea than coming at the thing with a power tool. Here's the arithmetic: volume of item = v density titanium = d_t density water = d_w weight in air w_a = v*d*g weight in water w_w = w_a - v*d_w*g w_w/w_a = (w_a - v*d_w*g)/w_a = 1 - d_w/d_t plugging in d_w = 1 g/cc d_t = 4.5 g/cc w_w/w_a = 1 - 1/4.5 = .78 If it's steel: w_w/w_a = 1 - 1/7.8 = .87 Most jewellers would have a setup that can weigh something immersed in water, it's how they tell themselves what the material is. If they say they don't then you are probably being had.

Re:

[florescent_beige (608235)]

It's effectively the same thing but the weight ratio is more practical. The volume of jewellery is so small that reading the change in water level in a graduated cylinder is really hard. It's generally smaller than the meniscus.

Plus most jewellers are already set up to do the water-weighing.

Interesting!

[Poromenos1 (830658)]

Next up: Test if your explosives have gone bad by detonating them.

Re:

[Kazymyr (190114)]

If you know of a more reliable way, I'd like to hear about it. No, seriously.

Re:Interesting!

[BlueParrot (965239)]

If you know of a more reliable way, I'd like to hear about it. No, seriously.

Physics to the rescue:
http://en.wikipedia.org/wiki/Elitzur-Vaidman_bomb-tester [wikipedia.org]

GRIND THIS!

[denzacar (181829)]

Apparently, Google [google.com] has "interesting" sense of humor regarding titanium products.

Titanium: not recommended for rings

[steveha (103154)]

I read a story about a couple who loved bicycling (and loved their titanium bicycle frames). They decided to have rings made from titanium.

One day the guy had some kind of accident, and his ring finger was mashed; it swelled up badly. They took him to the emergency room. In the ER, someone got out the cutters to cut the ring off the swollen finger. Whoops, titanium. The cutters (probably simple diagonal cutters) had no problem with the usual soft gold rings, but titanium was too hard! They wound up getting a Dremel tool or the equivalent and cutting the titanium ring off (very carefully, I imagine).

The moral of the story: if you get a titanium ring made, maybe you should wear it like a necklace.

P.S. Merry Christmas everyone.

steveha

They can be cut off.

[raygundan (16760)]

I know an ER doc who thought the same thing, until somebody came into her ER with one, and it was as trivial to cut off as anything else. Even if they lack a proper cutting tool, you can just squeeze it until it shatters. Titanium is strong, but it's not like a ring made of the stuff is somehow immune to being cut or broken. Hospitals are full of interesting tools, and it sounds like even in your story, they improvised fairly well.

Re:Titanium: not recommended for rings

[Nexzus (673421)]

About 18 years ago, I was on an underwater oil-drilling rig, when the mission we were "tasked" to perform by the navy went horribly wrong, and the rig started taking on water. I was running frantically running through cold freezing water towards a closing hydraulic door. I didn't make it in time, but I stuck my hand in the opening, and the door was stopped by my titanium wedding band. A colleague had found me, cut the hydraulic power to the door, and saved me. Earlier I had almost flushed it down the toilet. Good thing I didn't.

Couple hours later I met some aliens.

(Yeah, I know, but it sounds better in 1st person.)

The power to the door was pneumatic though

[Dr_Barnowl (709838)]

.. not hydraulic

Re:Titanium: not recommended for rings

[dbIII (701233)]

I must be missing the reference here...

An abysmal movie (The Abyss) that actually got some physics right but certainly not that bit.

Re:

[1729 (581437)]

Actually, titanium rings can be cut off fairly easily, at least according to the guy who made my wedding band:

http://boonerings.com/faq.htm#4 [boonerings.com]

Tungsten carbide rings are difficult to cut, but they can safely be cracked with vise grips:

http://www.trewtungsten.com/remove.php [trewtungsten.com]

What kind of pansy want's Titanium?

[Colin Smith (2679)]

Titanium is a woman's metal. Real men use Tungsten.
 

It reminded me of something that I had happen

[edwardpickman (965122)]

We were building a rig for a show and there were a lot of surplus aitcraft parts around. I found a large bracket that was perfect but it needed an extra hole drilled in it. The piece was light enough I assumed it was aluminum. I was using a hardened drill bit that should have cut through stainless. After five minutes I checked it and I barely scratched the surface. Aircraft Aluminum can be fairly hard but it seemed rediculous so I tried again but still nothing. I flipped over the part and there stamped/cast on the otherside was Titanium. Needless to say I gave up. All I managed to do was kill a good drill bit. If it seems really light for it's size and can't easily be scratched there's a good chance it's Titanium.

So what's next? platinum?

[sectionboy (930605)]

someone please tell me how to tell if there's real platinum in my Capital One® platinum Card, I always want to know.

Re:color, texture, weight

[Alaria Phrozen (975601)]

Wtf is with these fake links? Do you get money or something for that stupid city?

Re:Mods smoke crack

[jcuervo (715139)]

Shitcock [penny-arcade.com]

Re:

[Smidge204 (605297)]

The article I clicked on - the only link in the summary as I write this - leads to a page that has both a huge photo on top showing the two side by side (titanium vs steel) but also a video where they grind various items. The difference is very noticeable.

=Smidge=

Re:

[YrWrstNtmr (564987)]

It has good tensile strength and low weight but few applications warrant the additional expense.

Wrong. Several I can think of. Here's a couple that I have personal experience with.
Bicycles. A Ti bike is a noticeably different ride than other materials.
Eyeglasses. Steel contains quite a bit of nickel. Many people are allergic to it, and get a rash when in constant contact with it. So, in eyeglasses, you have a choice between regular steel, Ti, or plastic. Guess which wins.

Re:

[YrWrstNtmr (564987)]

After having steel framed glasses for many years, and started getting a skin reaction exactly where the frames touch my skin...I asked the optometrist about it. She said "oh...you have nickel allergy. You need something else besides steel frames."

Bought the (too expensive) Ti frames, and the condition went away almost immediately. Within days. Couple years later, tried another pair of steel ones. It started coming back. All Ti from then on.

And the Ti frames are significantly stronger/more flexible.

Re:Not Just Titanium

[ScrewMaster (602015)]

If you were testing Adamantium, those sparks were probably from your grinding wheel being worn down to a nub.

Re:wow

[techno-vampire (666512)]

You don't even need that much heat. Just warm it in your hands, and if you get a faint pine smell it's amber.