Titanium question

[Alero]

Are there a buch of cheap alloys out there? I remember several years ago that someone showed me a Ti sample. It was barely more than the thickness of paper and about an inch wide. I could just barely bend it and when I let go it snapped right back into shape.

Well, last weekend I was at Whole Earth and saw a Ti Spork for sale for around 10 bucks. I thought it was cool and was going to buy it, but when I flexed it a little I found that it was very easy to bend and didn't snap back to it's original shape. It felt more like aluminum.

So when you buy aftermarket things like flashlight clips (and sporks!), do you have a way of knowing if it's really pure Ti or if it's a chep alloy or maybe even just Ti colored?

 

[KeyGrip]

Most Ti is an alloy anyway. Like aluminum, Ti is mixed with other metals to give it certain characteristics. The only way to tell, apart from being a really good metallurgist, is to ask the manufacturer and hope they know what they're doing.

 

[kongfuchicken]

Titanium has a low magnetic signature, is very nonreactive chemically and doesn't conduct heat as well as other metals.
Comparing with known metals, it's probably possible to get an idea but I read somewhere the only way to be 100% sure is to take a sample for analysis.

I think someone mentioned shaving a bit off and burning it for a distinct color... I can't remember where I heard that though.

 

[Alero]

But in the case of the Ti spork, I shouldn't have been able to bend it as easy as any old cafeteria spoon should I? And real Ti should snap back into shape shouldn't it? Just making sure I'm not crazy here!

 

[KeyGrip]

Ti isn't necessarily springy, in fact most ti alloys are more toward the brittle side. I don't know what was up with that spork, but I have a SnowPeak Ti spoon that I can bend to take a set. It all depends on the alloy.

 

[optodoofus]

I think someone mentioned shaving a bit off and burning it for a distinct color... I can't remember where I heard that though.

This was described in Popular Science a while back (in the How To 2.0 section, I think). They tested a bunch of allegedly titanium things (like golf clubs, etc.) to see which had real titanium in them.

Here is a link to the online archive of the article.

http://www.popsci.com/diy/article/2007-12/titanium-or-plain-ol-steel

optodoofus

 

[StarHalo]

Keep in mind that Ti isn't miracle metal, it's just the metal with the best strength-to-weight ratio. It's roughly as strong as stainless steel; If you can bend a 2mm thick strip of stainless steel (as you'd find on a utensil), the titanium will bend with the same amount of effort. The only difference is that the Ti will be almost half the weight of the SS. Titanium also has poorer spring memory than stainless, as noted by McGizmo with his Ti 15mm split rings; you can't open them very much before they simply don't spring back anymore (I use and have gotten great results from his thicker 32mm ring).

If you want sheer I-can't-faze-it strength, you'll have to move up to tungsten, which isn't found in consumer products except for jewelry.

 

[McGizmo]

......Titanium also has poorer spring memory than stainless, as noted by McGizmo with his Ti 15mm split rings; you can't open them very much before they simply don't spring back anymore (I use and have gotten great results from his thicker 32mm ring).
.......

Ti is not as elastic as some spring stainless steels but is more elastic than the typical 300 stainless series used for many items. CP is typically not as springy as 6-4 Ti; or at least that has been my experience. I am not a metallurgist nor do I claim to know much about the various metals but many metals can be treated to change their physical properties. A metal can be annealed which leaves it much more malleable (bendable) than it would be if it were in a semi hard or hard state. I personally haven't encountered a better material than 6/4 Ti for the pocket clips if you want a material that won't rust easily and I haven't seen many pocket clips that have the memory of a good Ti clip; even some of the spring steels which do rust readily. :shrug:

The range of properties available in Ti alloys is quite extensive and lumping them all together with a common set of claimed characteristics is very misleading.

 

[precisionworks]

The range of properties available in Ti alloys is quite extensive and lumping them all together with a common set of claimed characteristics is very misleading.

Well said, McGizmo ... the fact that I love your lights not withstanding 6/4 Ti (technically known as Ti-6Al-4V) has become the standard alloy against which other alloys must be compared when selecting an alloy for a specific application. 6/4 Ti has been consistently responsible for about 45% of all industrial application.

Are there a buch of cheap alloys out there?

Yes and no. If you buy from a reputable metals supplier, that supplier can & will provide the mill certs that show the exact alloy composition, date of manufacture, lot number & heat number, etc. If you buy low dollar alloy from China, chances are that there are impurities or dilutants which would not pass accepted world standards.

For instance, 6/4 Ti can have these maximum percentages of impurities:

N .05
C .10
H .0125
Fe .30
O .20

These are miniscule trace amounts, hard to do using the best processing practices available today. Even harder to achieve in developing countries.

do you have a way of knowing if it's really pure Ti

Buy from a reputable manufacturer. Expect the item to cost 2x to 4x the price of the same part made from any other metal.

 

[Glasstream15]

In the late 90s I was at AlliedSignal Aerospace and we were using a lot of CP Titanium for flanges. We had to have a certain, relatively high, level of impurities in order to stamp the parts without them cracking. The best supplier we found was Russia. Scrapped Alfas. Nuclear Attack Submarines with Titanium hulls. Perfect consistency for stamped flanges.

 

[SimpleIsGood229]

For what it's worth, the Ti clips on my Spyderco Tasman Salt and Pacific Salt seem to be noticeably more resilient than the stainless clips on my other Spydies.

 

[tvodrd]

What Don said! Pure Ti if bent will stay that way. An easy way (other than weight/volume to quick check if something is really Ti is to touch it to a grinding wheel. Ti will give you bright white sparks as opposed to orange for most steels, and none for aluminum. (Like I'm about to take my Titan out to the garage and check! :green: ) Larry