what are titanum frames?

I

ipm

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Feb 26, 2009
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When people of this forum talk about 'titanium' frames/handles what are they refering to?

It certainly is not pure titanium.

Is it generally ASTM: 6Al4V Titanium Alloy or something more exotic for knife use in particular?

Whatever it is, it must be heat treated in some fasnion to mimic the process used on stainless (ex. 330). Is this correct?

Also where are these alloys made typically?

This is for no particular reason or wanting to know what is better or worse in terms of materials and processes.

I am just interested.
 
The handle material for Chris Reeve's Sebenza is indeed 6A14V Titanium. That's the limit of my knowledge on the subject, others with more info should be chiming in shortly.
 
They are talking about the same thing as the manufacturers talk about when they sell a knife with Ti liners, handles etc. Benchmade 760ti for example, what did you think they meant?
 
Yeah, it's usually 6Al4V alloy (probably because it's cheap). The best reason for Ti, (in my opinion), is that it can be used for integral framelocks without the weight of steel. I have no idea where the smelters are for this stuff.
 
Titanium Alloys: At $50.00 per pound commercially pure I wouldn't be so aghast. Alot of BF members have a knife or knife collection going into many thousands of dollars I'd wager. I would glady buy a pound just to get the few ounces needed for
a machine shop to cut me some scales.
 
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Most or all of the references to titanium frames/handles I've seen are for the '6Al-4V' type of Titanium alloy. Based upon the name ('6Al-4V'), and what I've found on a Google search so far, this is approximately 6% Aluminum (hence the '6Al') and 4% Vanadium ('4V') mixed with other elements (Carbon, Hydrogen, Iron, Nitrogen, Oxygen) in smaller percentages with the Titanium making up the balance & majority of the alloy. See these links for some more info:

http://www.suppliersonline.com/Research/Property/metals/2536.asp

http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MTP641
 
One of the main reasons for the use of 6AL4V is that it is the most common of all of the Titanium alloys and comprises over 50% of all the Titanium alloys made.

6AL4V is also much harder than CP1 Titanium

CP1 on the Vickers scale is about 200 / I don't think the Rockwell C scale goes low enough to measure CP1.
6AL4V on the Vickers scale is about 340 / in the annealed state about 36 if STA then about 41 on the Rockwell C scale.
 
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J.Mattson said:
Is there any reason why this particular alloy is used?
Click to expand...

Found this interesting explanation on Wikipedia ( http://en.wikipedia.org/wiki/Titanium_alloy ):

"Although "commercially pure" titanium has acceptable mechanical properties and has been used for orthopedic and dental implants, for most applications titanium is alloyed with small amounts of aluminium and vanadium, typically 6% and 4% respectively, by weight. This mixture has a solid solubility which varies dramatically with temperature, allowing it to undergo precipitation strengthening. This heat treatment process is carried out after the alloy has been worked into its final shape but before it is put to use, allowing much easier fabrication of a high-strength product."

I'm glad this thread was posted. Hadn't even considered WHY so many makers use this particular alloy. In the process of searching for answers to many of these questions, I'm getting some more education here. This is what makes this forum SO BEAUTIFUL...
 
Yeap, most consumer Titanium products is not pure titanium but rather an alloy, this allows easier machining and relatively easier welding. Welding any Ti alloy is still very hard.

Now what I want to know is what do they use to cut the Titanium slabs?
 
Yeap, most consumer Titanium products is not pure titanium but rather an alloy, this allows easier machining and relatively easier welding. Welding any Ti alloy is still very hard.

Now what I want to know is what do they use to cut the Titanium slabs?
 
Obsessed with Edges said:
Found this interesting explanation on Wikipedia ( http://en.wikipedia.org/wiki/Titanium_alloy ):

"Although "commercially pure" titanium has acceptable mechanical properties and has been used for orthopedic and dental implants, for most applications titanium is alloyed with small amounts of aluminium and vanadium, typically 6% and 4% respectively, by weight. This mixture has a solid solubility which varies dramatically with temperature, allowing it to undergo precipitation strengthening. This heat treatment process is carried out after the alloy has been worked into its final shape but before it is put to use, allowing much easier fabrication of a high-strength product."

I'm glad this thread was posted. Hadn't even considered WHY so many makers use this particular alloy. In the process of searching for answers to many of these questions, I'm getting some more education here. This is what makes this forum SO BEAUTIFUL...
Click to expand...

The wiki article is talking about engineering applications, not knife handles. Trust me, it's not the same.

Some handles I know to be 6-4 Ti because the maker says so.
Some don't state and it could easily be CP Ti. (Commercially pure Ti, essentially pure titanium). CP is used as an alloy all on its own in some aerospace applications.

I don't have cost comparisons between the two.
(I mostly don't track costs, only performance at work.)

For a knife handle CP would be as good as 6-4.
 
IGotStabbed said:
Yeap, most consumer Titanium products is not pure titanium but rather an alloy, this allows easier machining and relatively easier welding. Welding any Ti alloy is still very hard.

Now what I want to know is what do they use to cut the Titanium slabs?
Click to expand...

NOT TRUE!

CP Ti is easier to machine than 6Al-4V Ti.
 
knarfeng said:
NOT TRUE!

CP Ti is easier to machine than 6Al-4V Ti.
Click to expand...

Which, for me anyway, begs the question:

WHY is CP Ti easier to machine than 6Al-4V? Something to do with differences in hardness/toughness, or is it something else? If I understood the Wiki reference correctly, a major advantage of 6Al-4V is the ability to fabricate/form/machine the metal BEFORE heat treating is done. I would think this would make it very attractive to manufacturers? Just curious...
 
My guess would be the vanadium and carbon in the alloy will form vanadium carbides, which are very hard and give the alloy much more abrasion resistence than pure titanium, thus making it more difficult to machine.Mind you, that's just a guess based on what happens to steel when you put that much vanadium in the alloy. ;)
 
yablanowitz said:
My guess would be the vanadium and carbon in the alloy will form vanadium carbides, which are very hard and give the alloy much more abrasion resistence than pure titanium, thus making it more difficult to machine.Mind you, that's just a guess based on what happens to steel when you put that much vanadium in the alloy. ;)
Click to expand...

Vanadium forms carbides in steel because there is carbon in the steel.
There is no carbon in 6-4 Ti, so vandium carbides can't form in 6-4 Ti..

Would somebody show me where in the wiki article it says that 6-4 is easier to machine than CP Ti? If it says that I cannot find it. If it says that it is wrong.

6-4 is easier to work with (machine, super plastic form, etc.) than a lot of the other Ti alloys. It is not easier to work with than CP Ti.
 
I wouldn't be surprised at all if the no-name Ti is CP. It is cheaper and easier to machine and can be obtained from China and Russia. When Titanium bicycles were coming from China and Russia they often used CP, which was not as good as the typical American Ti bicycle tubing 3Al2.5v.

6Al4v is stronger than 3al2.5v but cannot be formed into tubing so for bike tubes its produced as a sheet then folded over and welded like in the Litespeed blade. The result is an aero shape tube because it is near impossible to form into a circular tube. The marketing people will sell this as an advantage even though its often heavier.

In the bicycle world if they don't tell you it is 6Al4V Ti then it likely isn't. That would be like making a knife with s30v and labeling the blade as "stainlesss". If they are using a premium steel or Ti I would think the marketing people would go the extra step to let you know.
 
Titanium 6AL4V is used in most commercial applications where titanium is the material of choice for whatever reason.

The reason it is used for knife is handles, is Strength, lightweight, withstands lateral stress as well as all stress very well as titanium has great toughness (bend don't break), it is very stable at both ends of the temperature spectrum both hot and cold, and its does not rust, salt water, most chemicals, etc. it simply does not rust and for all practical purposes it does not snap, chip or break. It will indent because it is softer than steel but again for all practical purposes it will not break, snap, chip, etc. It is also highly abrasion resistant.

Titanium alloys come in three classes alpha, beta and alpha betas with 6AL4V being in the alpha category.

I have all of the rockwell C hardness data for nearly all variants of Titanium and if memory serves 6AL4V is about 34 Rockwell C with certain variants of beta titanium coming in over 40 Rockwell C, the highest Rockwell C for 6AL4V is for a variant identified as 6AL4V STA and it has a rockwell C of about 38. Nobody hang me if these numbers aren't exactly spot on as my Titanium file folder is at my office and I'm writing this from home.

Alot of 6AL4V is made here in the US, because titanium is softer than steel but not really what should be considered soft like aluminum most of the cutting is done with a water jet. Other methods can work and or used but water jet cutting is the best.

Mission knives old website used to have a titanium tutorial on it that was a wealth of information I have a copy of this in my knife file folder, but it was dropped from their web site when the new owner took over. I'll see if I can find it somewhere on the web and post a link. It was extremely informative.

Hope this helps.
 
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