Wheel Material
#1
07-15-2007, 02:10 PM
Wheel Material
There is a lot of talk of "soft" and "hard" wheels and of course their associated weight. I was looking at the Kinesis F110 wheels since they look great and found this....
Kinesis F110 wheels are forged of 6061-T6 aircraft quality aluminum making them strong yet very lightweight.
I dont really know much about wheel materials, but I am a structural engineer working the aerospace industry. 6061-T6 is a pretty poor material structurally and about the only thing we use it for is brackets since its pretty easy to bend in its heat treated condition. Evenso...most newer airplanes are going for better aluminum for even brackets. I have never seen 6061-T6 used for any primary structure, its just very weak.
On the other hand, 7075-T6 and 2024-T4 are "real" "aircraft quality" alloys (and associated heat treats). This is what has generally been used for wings, bulkheads,frames, skins.
So if 6061-T6 is good for a wheel and is "aircraft quality", then what the heck is the back stuff? I cannot think of anything too much worse than 6061 off the top of my head, but I am sure there are some worse alums.
Of course the process will make it different (i.e. cast versus forged), but still 6061 just isnt that great.
For ref, 6061-T6 has a Ftu of 44ksi die forged while 7075-T6 has an Ftu of 78ksi die forged...nearly 80% stronger.
mil-hdbk-5 provides material data and is public domain.
Kinesis F110 wheels are forged of 6061-T6 aircraft quality aluminum making them strong yet very lightweight.
I dont really know much about wheel materials, but I am a structural engineer working the aerospace industry. 6061-T6 is a pretty poor material structurally and about the only thing we use it for is brackets since its pretty easy to bend in its heat treated condition. Evenso...most newer airplanes are going for better aluminum for even brackets. I have never seen 6061-T6 used for any primary structure, its just very weak.
On the other hand, 7075-T6 and 2024-T4 are "real" "aircraft quality" alloys (and associated heat treats). This is what has generally been used for wings, bulkheads,frames, skins.
So if 6061-T6 is good for a wheel and is "aircraft quality", then what the heck is the back stuff? I cannot think of anything too much worse than 6061 off the top of my head, but I am sure there are some worse alums.
Of course the process will make it different (i.e. cast versus forged), but still 6061 just isnt that great.
For ref, 6061-T6 has a Ftu of 44ksi die forged while 7075-T6 has an Ftu of 78ksi die forged...nearly 80% stronger.
mil-hdbk-5 provides material data and is public domain.
#3
07-15-2007, 03:00 PM
There may be several reasons of practical purposes. Yes, 6061-T6 had decent ductility and this will help to absorb energy beyond the elastic limit (the wheel is essentially ruined at this point) in the event of a hard bump, etc.
I suspect cost and availability may be good reasons they dont use better alloys either.
Casting/forging probably doesnt change the strength of the material too much, but it may help at the part level due to potential porosity and added brittleness of the casting (getting a little out of my domain though).
I guess what surprises me (and I suppose it shouldnt) is that they call 6061-T6 an "aircraft aluminum". Heck, if you are going to say that than any alum is an aircraft aluminum...you can probably find many different alloys for nonstructural applications. Its not a bad material and I have used it a lot in prototyping because its cheap and easily formable...but by no means is ever used on anything truly structural (unless for some reason a higher ductility is needed). Never heard of that situation, but it could exist.
I am not too familiar with auto materials and usage, but aerospace is highly concerned with weight. So more money can be spent on better material to achieve lower weights. I think right now good alum is in shortage because of programs like the Boeing 787 and Lockheed Joint Strike Fighter.
I suspect cost and availability may be good reasons they dont use better alloys either.
Casting/forging probably doesnt change the strength of the material too much, but it may help at the part level due to potential porosity and added brittleness of the casting (getting a little out of my domain though).
I guess what surprises me (and I suppose it shouldnt) is that they call 6061-T6 an "aircraft aluminum". Heck, if you are going to say that than any alum is an aircraft aluminum...you can probably find many different alloys for nonstructural applications. Its not a bad material and I have used it a lot in prototyping because its cheap and easily formable...but by no means is ever used on anything truly structural (unless for some reason a higher ductility is needed). Never heard of that situation, but it could exist.
I am not too familiar with auto materials and usage, but aerospace is highly concerned with weight. So more money can be spent on better material to achieve lower weights. I think right now good alum is in shortage because of programs like the Boeing 787 and Lockheed Joint Strike Fighter.
Last edited by hozer; 07-15-2007 at 03:03 PM.
#4
07-15-2007, 04:45 PM
Haha...I doubt it. This is all very common knowledge if you work in the aerospace business. I really doubt I know more than the guys who make the wheels. I think there must be financial/mnfr/etc factors to consider that make true aerospace allows unpractical. Although, I wonder if true high end wheels would warrant stronger alloys?
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