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Discussion Starter #1
OK. Let's talk some HEAVY material property crap and understand why some specific materials have been chosen over others.

I have begun to immerse myself in book knowledge of materials. I will admit up front I have very little (if any) working experience with any of the high strength steels and super alloys out there. But the more I read, the more questions I seem to bring up.

Here are the materials I am interested in discussing:

4340
300m
Aermet100
AF1410
Titanium

While surfing through my Metals Handbook, I came accross an interesting set of tables that compares some ultra-high strength steels. (I am at home right now, but will post a picture of it in the morning tomorrow).

These tables show that AerMet100 and AF1410 have more than twice the fracture toughness of 300m and is described as being superior in fatigue failure when compared to the other steels. The book makes it sound like it is superior in fatigue by having a high resistance to fracture propagation.

It DOES show that the yield strength of AerMet100 is 250ksi (ultimate is 285 ksi), while 300m is 340 ksi for yield (and 180ksi ultimate). But it would "appear" that AerMet100 and AF1410 has a better fatigue failure resistance than 300m.

The AF1410 is described (by the book) as a steel replacement for titanium and was recently developed by the Airforce. Here is a quote: "This combination of strength and toughness exceeds that of other commercially available steels, and the alloy has been considered as a replacement for titanium in certain aircraft parts."

Other than cost, why would titanium NOT be a good choice for axles and ujoints?

I have a feeling this is going to come down to cost and availability. But AF1410 was developed for submarine hull steels, so it should be pretty readily available in large chunks. It also says it is available in rod (for axle applications).

Are there any thoughts or comments?

I have started to think about this because it seems that some are looking to "push" the envelope when it comes to high tech in our sport of wheeling and building. And I would like to try to be a little more knowledgable when it comes to material selection and why one is choosen over another (and maybe help to educate others.)

I will post those tables tomorrow.
 

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Shot in the wind here but I always thought Titanium didn't handle impacts as well as the others - meaning titanium if hit hard enough will just crack and break off .. no bending at all..


Am I way off???
 

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no

because it work hardens super fast

which makes it a bitch to machine

that is the reason it is so expensive, it is the worlds 4th most common metal (naturally available)
 

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WHAT IS 300M......IS THERE A NAME FOR THIS METAL???
 

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TRD said:
no

because it work hardens super fast

which makes it a bitch to machine

that is the reason it is so expensive, it is the worlds 4th most common metal (naturally available)
Keep sharp tools, dont dwell, use proper tool geometry, and it cuts just fine. Try it sometime. ;)
 

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I have only machined it once, but I used the same tooling I use every day. Nothing special. 12 dollar carbide inserts, etc.
 

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cool

i was told by a materials engineer that it is super hard to machine and that you need special tooling hence it costs a lot.

you'd think you would get an honest answer out of a proffessor:shaking:

guess not, atleast you got the right answer in the end

thanks bgreen
 

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There may be many different types and grades of titanium, so some of it might be expensive to machine. Just like Carbon steel, some of it cuts like butter, and some of it doesnt. In my experiance SS can be a bigger bitch to machine than titanium.

leave it to an engineer to talk out his ass :D
 

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bgreen said:
There may be many different types and grades of titanium, so some of it might be expensive to machine. Just like Carbon steel, some of it cuts like butter, and some of it doesnt. In my experiance SS can be a bigger bitch to machine than titanium.

leave it to an engineer to talk out his ass :D
replace him with her
and
ass with cunt ;)

I should have known better but that phd looks so shiny and bling bling :D
 

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71RCKCRZR RYAN said:
WHAT IS 300M......IS THERE A NAME FOR THIS METAL??? [/Q UOTE] 300m is a modified version of 4340 alloy - vanadium and a higher silicon content is added to the alloy. used for aircraft components, some alloy axles- summerbrothers, and i think mark williams uses this alloy for their axles- there may be other m.f.g of axles that use it. it is supposed to have excellent torque - type load carrying abilities. there are people on this board that can give a more detailed post on it's properties and suitable applications.
 

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stainless steal dave said:
71RCKCRZR RYAN said:
WHAT IS 300M......IS THERE A NAME FOR THIS METAL??? [/Q UOTE] 300m is a modified version of 4340 alloy - vanadium and a higher silicon content is added to the alloy. used for aircraft components, some alloy axles- summerbrothers, and i think mark williams uses this alloy for their axles- there may be other m.f.g of axles that use it. it is supposed to have excellent torque - type load carrying abilities. there are people on this board that can give a more detailed post on it's properties and suitable applications.

i heard 300m's are pieces of shit :confused:

btw they were joking :flipoff2:
 

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NOPE NOT A JOKE.......

I ALWAYS READ PEOPLE TALKING ABOUT 300M.....AND I BET YOU MORE THAN HALF DONT EVEN KNOW WHAT IT IS.WELL NOW I DO KINDA........

THNX:D
 

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bgreen said:
There may be many different types and grades of titanium, so some of it might be expensive to machine. Just like Carbon steel, some of it cuts like butter, and some of it doesnt. In my experiance SS can be a bigger bitch to machine than titanium.

leave it to an engineer to talk out his ass :D
the last time i was at the scrap metal dealer i buy my metal from scrap titanium was 10.00 lb.when i asked why so much i was told lockeed had to pay 25.00- 30.00 lb. to the steel mills new. don't know which alloy it was - seemed awful pricey to me maybe he was full of shit don't know what it sells for new...............................??????????
 

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I don't know specifically about titanium, but most of the pricey metels we use are pricey because of the more stringent manufacturing and testing processes that go into proofing the foundry lots for the specified yield strengths.

Someone correct me if I'm worng, but for competition, they check your axle shafts for ferrous content.
 

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Discussion Starter #20
Here is the figure I was referring to.

Fracture Toughness defined: "Fracture toughness, in the most general of definitions, is the ability of a material to withstand fracture in the presence of cracks."

So here is what I am seeing, Aermet100, AF1410, and 300m all have similar yield strengths. But Aermet100 and AF1410 both have much higher properties and strength when it comes to crack propogation (and fatigue life????).
 

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