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 Post subject: Ti-6Q2 vs Ti6Al4
PostPosted: Mon May 16, 2016 5:58 pm 
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Joined: Mon Sep 01, 2014 4:58 pm
Posts: 185
After reading a bit about Ti-6Q2 on http://shop.titaniumspindles.com/main.sc, it seems that the material is potentially stronger and/or stiffer (when heat treated) than Ti6Al4. However, I can't seem to find to much info about the material. I haven't really found any other consumer available products made from it either, so I'm wondering if anyone know anything interesting about how the materials compare to each other?

Are the claims on titaniumspindles.com? And if they are; why aren't most industries replacing the use of Ti6Al4 with Ti-6Q2? I understand that material/manufacturing price might be a part of all this (although the prices in the link isn't bad at all), but there are lots of high end products/manufacturers (also costumers) out there, that would be willing to pay a bit extra for something a bit better. If the material really is "better", one would expect there to be a lot of bolts and other parts made from it.

I'm really curious about the material and I hope some of you might be able to give me some insight on the subject.


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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Mon May 16, 2016 6:31 pm 
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Joined: Fri Feb 10, 2012 4:27 pm
Posts: 555
Ti-6Q2 was created for the aerospace industry. Ti-6Q2, which is a brand name for Ti-6Al-2Zr-2Sn-2Mo-2Cr-0.25Si, is a proprietary alloy produced by RTI metals. With cutbacks in US defence spending, lots of excess Ti-6Q2 was apparently dumped onto the market for cheap a couple of years ago.

This isn't to say Ti-6Q2 is a lousy material, just consider the economics of acquiring raw material.

Ti-6Q2 modulus is 16.2 msi (111.7 GPa) in bar form. Ti-6Al-4V (more commonly known as grade 5) has a modulus of 16.9 msi (116.5 GPa) in bar form according to the US Metallic Materials Properties Development and Standardization-01 document. So, it is actually marginally LESS stiff than Ti-6Al-4V, but for all intents and purposes its essentially the same. not something that can be felt out on the road. no one is strong enough to bend/deform pedal spindles on the road. I don't know about density, but they are probably very close.

Ti-6Q2 and Ti-6Al-4V will have differing properties in fracture and fatigue resistance, also depending on how you heat treated it, you could make Ti-6Q2 stiffer than T-6Al-4V, but not by much. They are meant for different applications- Ti6Q2 most likely has to deal with higher temperatures than Ti6Al4V. I don't know which one is better in fatigue/fracture resistance, but if it's bar stock going to the aerospace or medical industry it's going to be high grade.

You are mistaken that stiffer is always better, and new materials are not always adopted based on the economics involved. The medical industry actually wants LESS stiff titanium to better match the modulus of bone. in aerospace some flex is sometimes designed into aircraft parts. You need to understand what engineers mean by TOUGHER and STIFFER, (toughness is the resistance to fatigue, stiffness is the resistance to elongation under stress) and that depending on the desired part, these properties arent always desired.

As for the economics of adopting a new material, any material developed for the Medical and Aerospace industry (the 2 biggest industries to use titanium, also , oil and gas) has to go through very rigorous and expensive standardisation and testing. unless our new alloy has a HUGE advantage or a very specific niche application, you aren't displacing an alloy which has been tested and proven (e.g. Ti-6Al-4V ) because it takes a very long time ( 3-5 years for most medical applications) and alot of money, something most enterprises are not willing to undertake.- i.e. if it ain't broke, don't fix it. The bicycle industry is not big enough for anyone to actually go develop a Ti alloy blend custom for the needs of bikes. Ti-6Al-4V serves us quite well enough.


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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Mon May 16, 2016 7:41 pm 
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Joined: Mon Sep 01, 2014 4:58 pm
Posts: 185
davidalone wrote:
Ti-6Q2 was created for the aerospace industry. Ti-6Q2, which is a brand name for Ti-6Al-2Zr-2Sn-2Mo-2Cr-0.25Si, is a proprietary alloy produced by RTI metals. With cutbacks in US defence spending, lots of excess Ti-6Q2 was apparently dumped onto the market for cheap a couple of years ago.

This isn't to say Ti-6Q2 is a lousy material, just consider the economics of acquiring raw material.

Ti-6Q2 modulus is 16.2 msi (111.7 GPa) in bar form. Ti-6Al-4V (more commonly known as grade 5) has a modulus of 16.9 msi (116.5 GPa) in bar form according to the US Metallic Materials Properties Development and Standardization-01 document. So, it is actually marginally LESS stiff than Ti-6Al-4V, but for all intents and purposes its essentially the same. not something that can be felt out on the road. no one is strong enough to bend/deform pedal spindles on the road. I don't know about density, but they are probably very close.

Ti-6Q2 and Ti-6Al-4V will have differing properties in fracture and fatigue resistance, also depending on how you heat treated it, you could make Ti-6Q2 stiffer than T-6Al-4V, but not by much. They are meant for different applications- Ti6Q2 most likely has to deal with higher temperatures than Ti6Al4V. I don't know which one is better in fatigue/fracture resistance, but if it's bar stock going to the aerospace or medical industry it's going to be high grade.

You are mistaken that stiffer is always better, and new materials are not always adopted based on the economics involved. The medical industry actually wants LESS stiff titanium to better match the modulus of bone. in aerospace some flex is sometimes designed into aircraft parts. You need to understand what engineers mean by TOUGHER and STIFFER, (toughness is the resistance to fatigue, stiffness is the resistance to elongation under stress) and that depending on the desired part, these properties arent always desired.

As for the economics of adopting a new material, any material developed for the Medical and Aerospace industry (the 2 biggest industries to use titanium, also , oil and gas) has to go through very rigorous and expensive standardisation and testing. unless our new alloy has a HUGE advantage or a very specific niche application, you aren't displacing an alloy which has been tested and proven (e.g. Ti-6Al-4V ) because it takes a very long time ( 3-5 years for most medical applications) and alot of money, something most enterprises are not willing to undertake.- i.e. if it ain't broke, don't fix it. The bicycle industry is not big enough for anyone to actually go develop a Ti alloy blend custom for the needs of bikes. Ti-6Al-4V serves us quite well enough.


Thanks for the answer. I did not say that stiffer is always better though (did I?). At least that's not what I ment. I do understand that stiffness and toughness isn't the same thing (although often reflecting one another). I'm studying for a masters degree in construction engineering, so I do understand some basic principles. But as I'm not studying mechanical engineering and I'm only in my second year out of five, my knowledge is indeed limited. Especially when it comes to industries adopting new materials and such. But if the material is better for some purposes (although marginally), one would think there was at least some manufacturers using it, for products that's mostly marketed against industry purposes, but available for consumers (i.e. bolts/fasteners etc.)?


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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Mon May 16, 2016 9:05 pm 
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Joined: Mon Sep 01, 2014 4:58 pm
Posts: 185
I asked the guys at titaniumspindles.com, and I got a reply almost right away. They told me that the material is 2-3 times more expensive than Ti6Al4, and more time consuming to produce (don't know if this is linked with the higher price, or if it's another issue on top of that). The only reason they sell it as cheap as they do is because they got it really cheap after the F-22 project was cancelled. They also sent me a link with some info, should anyone be interested;)


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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Mon Jun 06, 2016 10:04 am 
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Joined: Fri Feb 10, 2012 4:27 pm
Posts: 555
HaakonJohansen wrote:
davidalone wrote:
Ti-6Q2 was created for the aerospace industry. Ti-6Q2, which is a brand name for Ti-6Al-2Zr-2Sn-2Mo-2Cr-0.25Si, is a proprietary alloy produced by RTI metals. With cutbacks in US defence spending, lots of excess Ti-6Q2 was apparently dumped onto the market for cheap a couple of years ago.

This isn't to say Ti-6Q2 is a lousy material, just consider the economics of acquiring raw material.

Ti-6Q2 modulus is 16.2 msi (111.7 GPa) in bar form. Ti-6Al-4V (more commonly known as grade 5) has a modulus of 16.9 msi (116.5 GPa) in bar form according to the US Metallic Materials Properties Development and Standardization-01 document. So, it is actually marginally LESS stiff than Ti-6Al-4V, but for all intents and purposes its essentially the same. not something that can be felt out on the road. no one is strong enough to bend/deform pedal spindles on the road. I don't know about density, but they are probably very close.

Ti-6Q2 and Ti-6Al-4V will have differing properties in fracture and fatigue resistance, also depending on how you heat treated it, you could make Ti-6Q2 stiffer than T-6Al-4V, but not by much. They are meant for different applications- Ti6Q2 most likely has to deal with higher temperatures than Ti6Al4V. I don't know which one is better in fatigue/fracture resistance, but if it's bar stock going to the aerospace or medical industry it's going to be high grade.

You are mistaken that stiffer is always better, and new materials are not always adopted based on the economics involved. The medical industry actually wants LESS stiff titanium to better match the modulus of bone. in aerospace some flex is sometimes designed into aircraft parts. You need to understand what engineers mean by TOUGHER and STIFFER, (toughness is the resistance to fatigue, stiffness is the resistance to elongation under stress) and that depending on the desired part, these properties arent always desired.

As for the economics of adopting a new material, any material developed for the Medical and Aerospace industry (the 2 biggest industries to use titanium, also , oil and gas) has to go through very rigorous and expensive standardisation and testing. unless our new alloy has a HUGE advantage or a very specific niche application, you aren't displacing an alloy which has been tested and proven (e.g. Ti-6Al-4V ) because it takes a very long time ( 3-5 years for most medical applications) and alot of money, something most enterprises are not willing to undertake.- i.e. if it ain't broke, don't fix it. The bicycle industry is not big enough for anyone to actually go develop a Ti alloy blend custom for the needs of bikes. Ti-6Al-4V serves us quite well enough.


Thanks for the answer. I did not say that stiffer is always better though (did I?). At least that's not what I ment. I do understand that stiffness and toughness isn't the same thing (although often reflecting one another). I'm studying for a masters degree in construction engineering, so I do understand some basic principles. But as I'm not studying mechanical engineering and I'm only in my second year out of five, my knowledge is indeed limited. Especially when it comes to industries adopting new materials and such. But if the material is better for some purposes (although marginally), one would think there was at least some manufacturers using it, for products that's mostly marketed against industry purposes, but available for consumers (i.e. bolts/fasteners etc.)?


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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Mon Jun 06, 2016 10:05 am 
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Joined: Fri Feb 10, 2012 4:27 pm
Posts: 555
HaakonJohansen wrote:
davidalone wrote:
Ti-6Q2 was created for the aerospace industry. Ti-6Q2, which is a brand name for Ti-6Al-2Zr-2Sn-2Mo-2Cr-0.25Si, is a proprietary alloy produced by RTI metals. With cutbacks in US defence spending, lots of excess Ti-6Q2 was apparently dumped onto the market for cheap a couple of years ago.

This isn't to say Ti-6Q2 is a lousy material, just consider the economics of acquiring raw material.

Ti-6Q2 modulus is 16.2 msi (111.7 GPa) in bar form. Ti-6Al-4V (more commonly known as grade 5) has a modulus of 16.9 msi (116.5 GPa) in bar form according to the US Metallic Materials Properties Development and Standardization-01 document. So, it is actually marginally LESS stiff than Ti-6Al-4V, but for all intents and purposes its essentially the same. not something that can be felt out on the road. no one is strong enough to bend/deform pedal spindles on the road. I don't know about density, but they are probably very close.

Ti-6Q2 and Ti-6Al-4V will have differing properties in fracture and fatigue resistance, also depending on how you heat treated it, you could make Ti-6Q2 stiffer than T-6Al-4V, but not by much. They are meant for different applications- Ti6Q2 most likely has to deal with higher temperatures than Ti6Al4V. I don't know which one is better in fatigue/fracture resistance, but if it's bar stock going to the aerospace or medical industry it's going to be high grade.

You are mistaken that stiffer is always better, and new materials are not always adopted based on the economics involved. The medical industry actually wants LESS stiff titanium to better match the modulus of bone. in aerospace some flex is sometimes designed into aircraft parts. You need to understand what engineers mean by TOUGHER and STIFFER, (toughness is the resistance to fatigue, stiffness is the resistance to elongation under stress) and that depending on the desired part, these properties arent always desired.

As for the economics of adopting a new material, any material developed for the Medical and Aerospace industry (the 2 biggest industries to use titanium, also , oil and gas) has to go through very rigorous and expensive standardisation and testing. unless our new alloy has a HUGE advantage or a very specific niche application, you aren't displacing an alloy which has been tested and proven (e.g. Ti-6Al-4V ) because it takes a very long time ( 3-5 years for most medical applications) and alot of money, something most enterprises are not willing to undertake.- i.e. if it ain't broke, don't fix it. The bicycle industry is not big enough for anyone to actually go develop a Ti alloy blend custom for the needs of bikes. Ti-6Al-4V serves us quite well enough.


Thanks for the answer. I did not say that stiffer is always better though (did I?). At least that's not what I ment. I do understand that stiffness and toughness isn't the same thing (although often reflecting one another). I'm studying for a masters degree in construction engineering, so I do understand some basic principles. But as I'm not studying mechanical engineering and I'm only in my second year out of five, my knowledge is indeed limited. Especially when it comes to industries adopting new materials and such. But if the material is better for some purposes (although marginally), one would think there was at least some manufacturers using it, for products that's mostly marketed against industry purposes, but available for consumers (i.e. bolts/fasteners etc.)?



ummm no. Switching costs are high. you want to switch an entire assembly line over? then you'd have to explain to your long time Ti6Al4V supplier why you're ordering less, risking some valuable relationships. you'd need to consider if you're a big player you're probably holding on to futures contracts of Ti6Al4V already, so theres sunk costs there. then you'd need some downtime in your production line to recalibrate processes, clean ( no contamination!) re-train workers.... and time is money. Then you'd have to convince customers that your new magic titanium is superior to the normal titanium they've been using for years and worth the extra $1 per part you'll be charging them.

Then what happens when you switch back? same thing again. No one gives a rats ass if your bolt has an 10MPA UTS more than the normal bolt, because engineering products are already designed with a safety factor in mind - i.e. if your part is expected to see loads of 200MPA, you dont design for 200 MPA- you design for 300MPA (in aerospace, safety factor is 1.5-2.5 . safety factor for bolts is 8.5) . so a bolt that fails at 850MPA is actually only rated for use in 100MPA. who gives a rats ass if your 100MPA rated screw fails at 860MPA over the 850MPA screw? is it worth the extra $1?

As I said unless your material has a very clear and significant advantage, no one invests that kind of money and time just for a small advantage, especially over something that has to meet very stringent certifications, is good enough, and everyone is familiar with.

The desire for niche weight weenie parts is a very, very small component of manufacturing. for bicycles hobbyists, it's even smaller. The titanium spindles guys are a unique case you are not likely to see again.


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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Mon Jun 06, 2016 11:07 am 
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Joined: Mon Sep 01, 2014 4:58 pm
Posts: 185
No need to be condescending. I didn't mean to upset anyone, so I'm sorry if I did. It was just a question, followed up with a bit of info about the material. I do understand the limited use of the material after the guys at titaniumspindles.com told me about the much higher production costs over Ti6Al4. If the production cost was around the same though, I do think that certain aero/racing manufacturers/researchers would look into possible aspects for developing certain beneficial solutions. Think about experimental businesses like i.e. F1 racing. I'm not saying that it would completely change any market over night. But if material production costs was about the same (which it's not though), I do think that there would be markets willing to experiment with developing better solutions. Even if the improvements were small.


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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Tue Jun 07, 2016 11:50 am 
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Joined: Thu Mar 31, 2016 10:32 am
Posts: 145
I always associated toughness with impact/fracture toughness, not fatigue. I mean, fatigue causes cracking, but in my head toughness usually means something like Charpy.

I would be inclined to agree with the raw materials and logistics explanation. I don't think switching costs would be high. Mostly likely they do these in small batches, not an assembly line. They would just need to figure out the needed changes in feed rate, if even necessary at all, and plug that in. I don't think these guys contract enough titanium to make a dent in their supplier's production. Or their supplier could very well be trying to dump surplus stock at a discount, meaning they want their buyers to switch.

Although that's already pretty much been confirmed by other posts that they're buying surplus.

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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Wed Jun 08, 2016 11:51 am 
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Posts: 395
I learned that cheap spindles often are made of what they called medical grade titanium. But there is more than that and that is that they use often more "filler" in the product.

Titanium Grade Overview
http://www.supraalloys.com/titanium-grades.php

The purity of Grade 2 can differ as you can read here
http://www.thedabstore.com/blogs/news/9 ... l-purchase


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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Wed Jun 08, 2016 3:38 pm 
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Joined: Thu Mar 31, 2016 10:32 am
Posts: 145
Somehow I doubt that they're using unalloyed titanium.

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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Wed Jun 08, 2016 8:19 pm 
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Joined: Wed Feb 03, 2010 1:31 am
Posts: 464
HaakonJohansen wrote:
But if the material is better for some purposes (although marginally), one would think there was at least some manufacturers using it,


Lets use a current example. The aluminum body panels on the current Ford F-150 pickup truck. I suspect Ford was able to make them the same strength as the old steel panels being replaced. And equal to the steel panels still being used by Chevy and Dodge. And almost every other vehicle being made today. I think Ford used the aluminum body panels to get lighter weight. So payload goes up a little and fuel mileage goes up a little. Marginally. Not huge jumps. I would guess Ford has stacks of data and experiments proving the superiority of aluminum for body panels. But why are none of the other big car makers using aluminum? Why isn't Ford using aluminum in any of its other cars? Why didn't the whole world say Hallelujah, we have seen the light. And instantly change from steel to aluminum.

And I am a believer in Ford's aluminum panels. I honestly and truthfully think they are superior or at least equal to the steel panels being replaced. And you get the advantages of less weight, more payload, more mileage. Not sure about costs. Is aluminum more expensive than the old steel panels? Not sure. But the gains and disadvantages are about zero. It makes no difference in reality.


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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Wed Jun 08, 2016 10:34 pm 
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Posts: 406
Location: Cantabria
Then go to Europe and Japan and we are using BH steels for the panels and boron steels for the structural cell, to better stiffness to weight and energy absorption to weight ratios than in the aluminium bodies of the 90's (Audi, Jaguar, ...)

Even Ford uses steel for their German projects (Focus, Mondeo, etc.)

And yes toughness and fatigue are different stuff and toughness is measured in tests like the Charpy-V.




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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Thu Jun 09, 2016 4:19 am 
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Joined: Wed Feb 03, 2010 1:31 am
Posts: 464
XCProMD wrote:
Then go to Europe and Japan and we are using BH steels for the panels and boron steels for the structural cell,

Even Ford uses steel for their German projects (Focus, Mondeo, etc.)


Ford uses steel on their USA Focus cars. My brother owns a Ford Focus. If this BH steel and boron steel you claim is so superior, and the aluminum body panels used in the Ford F-150 pickup, why aren't they used on every single vehicle in the whole world? If its better, why not use it everywhere? Why intentionally make an inferior product?

Answer is probably its not much better if any better. Makes no difference other than to being different because its different. No real difference. Cost wise, I don't know if these superior methods are more expensive, less expensive, or no different than all the other methods.


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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Thu Jun 09, 2016 4:55 am 
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Joined: Fri Feb 10, 2012 4:27 pm
Posts: 555
HaakonJohansen wrote:
No need to be condescending. I didn't mean to upset anyone, so I'm sorry if I did. It was just a question, followed up with a bit of info about the material. I do understand the limited use of the material after the guys at titaniumspindles.com told me about the much higher production costs over Ti6Al4. If the production cost was around the same though, I do think that certain aero/racing manufacturers/researchers would look into possible aspects for developing certain beneficial solutions. Think about experimental businesses like i.e. F1 racing. I'm not saying that it would completely change any market over night. But if material production costs was about the same (which it's not though), I do think that there would be markets willing to experiment with developing better solutions. Even if the improvements were small.



Didn't mean to sound condescending.
It WOULD be doable if you were designing a whole new part from scratch and your new material has some small advantage. so say you had a new product and were putting together an assembly line or small batch production... sure. experiment away.

But if you were an established manufacturer of say, M5 TiAl4V bolts, making thousands a day, and you wanted to swap to Ti6Q2 just for a marginal increase in strength and toughness? no. that would not be economically feasible.


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 Post subject: Re: Ti-6Q2 vs Ti6Al4
PostPosted: Thu Jun 09, 2016 5:08 am 
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IMO it is rarely a case of one material being clearly superior. There are almost always trade-offs.
Is fatigue really a limiter for a special component intended to be used for only a short time ?
Is stiffer really required, or is "stiff enough" better when considering shock loading and rider fatigue, etc...

Marketing is one of those factors. Manufacturers want you to think their product is "better" so they tell you all the advantages of BH steel, or Boron steel...or aluminum...or Ti6Q2, and maybe they just don't mention the "negatives", like lower stiffness, or inferior corrosion resistance, etc..

Cost is another factor: will people actually pay more for it if it is just a tiny bit better, or if we can make them THINK it is better.

In the specific case of Ti6Q2, it looks like good stuff, but probably negligibly different than Ti6Al4V in a practical situation. Then, there is the marketing burden of convincing people that an unusual alloy is "just as good" or "better" than a familiar alloy.

Even among 6Al4V, I know from personal experience that cheap, no-name Ti bolts that are CLAIMED to be 6Al4V can twist off like peanut butter, while bolts from reputable suppliers with material certs and a QA program (like Pro-Bolt....no connection, I am just a customer) are stronger than most steel.

("Like peanut butter" is an exaggeration, but they were Ti bolts supplied with a stem from a major manufacturer and numerous ones broke well below their rated torque....and yes, I have numerous calibrated torque wrenches too! :)


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