65 rockwell titanium knives?

V

Vicarious Reality

Joined
Apr 9, 2008
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I founds something rather odd while reading about beta titanium

This company claims to be able to harden their titanium knives to 65 rockwell?!

Is this even possible, prior to seeing this i thought titanium could not get harder than 53-ish :confused:

Of course their specific alloy is a special secret mystery, do you think they could be nitridizing or carbidizing it somehow?

http://www.oceanmaster.com/KnivesFeatures.htm#DiveKnife
 
Looks pretty interesting. They emphasize that they don't use Ti from China and that their products are 100% American made... for the price I'd be interested to try one. It appears that handle of the Server model is taken directly from BM TSEK model.
 
Titanium nitride plating can get the hardness up to that level, I believe. But you can't sharpen it.

Maybe they are doing something like nitro-carburizing, which essentially case hardens the outer skin of the metal by forcing nitrogen into it?
 
There are multiple Titanium Nitride coatings. The hardest of which is AlTiN which can reach up to 90 HRC and the softest of which is TiN at 81 HRC.

Although it doesn't seem that Titanium Nitride is what this company is marketing. Although I've never heard of Titanium being treated to 65 HRC. Another possibility is that they are using tungsten carbide on the edge to achieve that high of a Rockwell.
 
Obviously we are not talking about coatings here but the actual titanium itself.

Imo, sounds like good marketing mixed with a bunch of BS.
 
Jason B. said:
Obviously we are not talking about coatings here but the actual titanium itself.

Imo, sounds like good marketing mixed with a bunch of BS.
Click to expand...


After doing a few cursory Google searches, it appears that Jason may be right. OceanMaster knives have been around for awhile and I even was able to find several references to them on BF dating back to 2002. Nothing favorable. The basic models offered do not seem to have changed much since then. KC is carrying them but not many reviews. A few pics show that one side is ground forming a chisel grind.

If they have in fact produced their own Ti that reaches the claimed RC hardness... then I think we would have heard a lot more about it...
 
I met those guys at the blade show a couple of years back, we were staying at the same hotel. Having had the "pleasure" of talking to 3 people that said it was "their" company I'm very happy to say I don't own a single thing from them.
One of them was very quick to give me his pitch, he was arrogant, uninformed and was probably far more accomplished at talking to people that don't know any better. The whole thing made for a rather unpleasant meeting, I quickly realised there was nothing I wanted to hear coming from them, made my excuses and promptly left.

I'll also add that they were all from mainland China and were nice enough to pass on a few smarmy veiled insults to my friend from Taiwan that was with me at the time. Infact it was my Taiwanese friend's "Chinese" apperance that instigated the conversation in the first place.
 
I've read U.S. military studies dating back to the 1970s showing beta titanium alloys hardened to Rc 60+ but they were rather brittle at that hardness, being used for face-plates on ballistic armor for vehicles. So it is possible, but unfortunately the website gives absolutely NO meaningful information about those knives at all, and as far as having specially-formulated beta titanium alloy, that is almost assuredly a complete load of fly-blown bull-crap.
 
You tell them Mecha !!!
My Ti sword can now be considered sub-zero treated as the temperature here was - 15 F !!! LOL . The chipmunks are deep in their holes so they won't be available for testing untill it thaws !
Mine has a Ti martensite !! Yes Ti Martensite for hardness and strength. I'm a metallurgist I know !!
 
Epic, Mete! Your sword may contain the following phases, in addition to alpha and beta crystal structures:

Alpha prime
Alpha double-prime
Beta prime

All of these martensite-like phases are possible with the right beta metastable titanium alloy, and they can be harder than martensite in steel, but the phases are a trade-off between ductility, toughness, hardness, of course!
 
Mecha said:
Epic, Mete! Your sword may contain the following phases, in addition to alpha and beta crystal structures:

Alpha prime
Alpha double-prime
Beta prime

All of these martensite-like phases are possible with the right beta metastable titanium alloy, and they can be harder than martensite in steel, but the phases are a trade-off between ductility, toughness, hardness, of course!
Click to expand...

You should just be called the "Ti Junkie".
 
MECHA MAKE MY DAMN UO! :D

Hmm I've had a mission ti knife, it was sweet.. wish I had held on to it...

I actually do own the blue blunt tipped "dive" knife, got it for under 40 bux... I might have to let Mecha test it out :)

The sheath is an utter piece of crap. The handle is crap.. The blade grind isn't bad. I bought it with intent on Mecha killing it with me :) (I live an hour away, so hopefully soon again we meet!)

And I understood from Mecha and other Ti sites, that 60 is crazy high on RC for Ti.. normal Ti we see here on the site is like 53-54 RC...

LUNCH!
 
While browsing custom knives I came across a Duane Dwyer custom which used SM-100 a "steel" which I had never heard of. So I pulled out my Knife Steel Chart app and searched SM-100. Well it turned out SM-100 is a Titanium alloy consisting of 60% Nickel and 40% Titanium.

Here is the description pulled from zknives:

"SM-100(Summit Materials) - Variation of the Crucieble NiTiNol 60 alloy. Composition was tweaked to improve manufacturing process, but exact numbers have not been published yet. Promotional materials refer to NASA tests and mention twice the life expectancy compared to AISI 440C, although the tests were done for bearings, not knives. Not sure why, but even Summit Materials own web page cites two different working hardness ranges 56-62HRC on the materials page and 57-64HRC on the home page. 2 HRC especially when we'retalking about 62 vs. 64HRC can translate into huge difference in edge holding, edge thickness etc. I'm trying to get more precise data. NiTiNOL knives are speced at 65HRC. Another point to consider, alloy has very low Young's modulus value 47-90 vs 200 and above on more conventional steels. Can't tell without testing an actual knife, but low Young's modulus could affect edge stability and strength negatively. In other words edges might require extra thickness to sustain themselves, which would definitely be a negative. Other Titanium and Cobalt alloys such as Talonite and Stelitte 6B, Stelitte 6K have the same problem with thick edges. Keep in mind, this is purely a guess, based on a particular property."

As you can see, according to this description SM-100 can be hardened to up to 64 HRC. This along with the info Mecha provided seems to confirm that it is possible for a Titanium alloy to be hardened to a HRC in the mid 60's.
 
Bring it down to the forge, Sloth! It would be interesting to see if the metal is titanium alloy or not.

Interesting info, Obsidian. Nitinol is a shape-memory metal, I believe. If its shape is deformed, heating it up a bit will make it re-form back into the original shape. Imagine that feature for a sword! :D

The low 50s is actually a really high rockwell C number for a titanium alloy. It's best not to get too wrapped up in the rockwell numbers, especially for exotic metals though. It's just a tiny diamond-tipped cone that gets pressed into the metal at a measured pressure, and records how far in the diamond penetrates. These hardness numbers are especially useful for measuring consistency and to make sure you've hit the mark in heat-treatment, but as I was told by a great sword-maker, the blade geometry and what's behind the edge is what's most important, and this varies depending on the alloy. For example, talonite reads somewhere in the low to mid 30s, yet the talonite blades I've seen and held were very thin.
 
I still have the piece of Nitinol I had to beg and plead for back in the '60s when it was new .It's really cool to watch people when you take it back to the original with a match ! SMAs have interesting applications in fields like medicine. The martensite reaction also is found in Maraging steels [Ni-Fe martensite , technically not " steel" as it has non carbon.] as those were developed I was working on my thesis
on similar Fe-Mn martensite .Maraging alloys can be found on top quality fencing swords and golf clubs ! We were NOT thinking of those things when we developed them !! So yes we have martensite other than in the Fe-C system. Martensite is a shear type reaction which occurs fast , speed of sound reaction.
 
Talonite (Stellite 6-BH), Stellite 6-B, and Stellite 6-K are basically Chrome cobalt alloys. Even though the HRC of Stellite 6-K is in the 43-47 range, you can't scratch it with a file at 60 HRC. They make tool bits, Sodium cooled valves for racing engines, rocket engine nozzles, bulldozer blade edges, saw teeth, machine gun barrels, heart valve cages, hip joints, etc. out of Stellite.
 
Oh 43-47 on stellite 6k is a lot higher rockwell reading than I thought! I suppose it varies among the dendritic cobalt alloys.

Seems like every advancement in metallurgy or material science goes straight onto golf club faces, Mete! :D
 
Wow nice collection Tiguy! :eek:

If you really want to lose your mind, ponder this: alpha double-prime crystalline structure in beta titanium is orthorhombic. RHOMBOID with asymmetrical geometry! Imagine the resistance to all forms of mechanical stresses.
 
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