Aluminum Rod material?

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desotoman
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Aluminum Rod material?

Post by desotoman » Sun Feb 11, 2018 1:25 pm

Does anyone know what the latest Aluminum Rod material is? Or does anyone know of a manufacturer that uses a aluminum material that actually gets stronger when its temperature increases? From what I understand when an aluminum rod increases in temperature it loses some of its strength.

Thanks for any help.

Tom

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Re: Aluminum Rod material?

Post by modok » Sun Feb 11, 2018 10:32 pm

I think it is true for every kind of aluminum, that it will be weaker the hotter it is, but pistons are aluminum and yet it still works right?
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Re: Aluminum Rod material?

Post by SupStk » Sun Feb 11, 2018 11:20 pm

A while back I quized GRP on the material used on the PRO rods. All I got was its proprietary.
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Re: Aluminum Rod material?

Post by tresi » Sun Feb 11, 2018 11:44 pm

Find you a large scrape yard. Assuming you have a scrap rod on hand. One that handles and sorts various grades of aircraft aluminum. They should have a gun style tester that burns off a small bit of the alloy in question. That will get you fairly close.

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Re: Aluminum Rod material?

Post by SupStk » Mon Feb 12, 2018 12:08 am

tresi wrote:
Sun Feb 11, 2018 11:44 pm
Find you a large scrape yard. Assuming you have a scrap rod on hand. One that handles and sorts various grades of aircraft aluminum. They should have a gun style tester that burns off a small bit of the alloy in question. That will get you fairly close.
Thats good information I didn't know before. Don't have a scrap rod but can get one. Not certain the local guys have that gun but will check it out.
Thanks!
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Re: Aluminum Rod material?

Post by Momus » Mon Feb 12, 2018 1:28 am

They're almost always made from 7075 T6511. There are stronger grades ie Kaiser's 7068T6511 that are also used in higher $ applications.
Better strength at temp than 7075 though info is hard to come by.

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Re: Aluminum Rod material?

Post by pdq67 » Mon Feb 12, 2018 5:32 am

Anybody know what Jager aluminum rods are made out of?

Supposedly they don't, "work harden(?)". or, "stretch(?)", with use like most aluminum rods do??

I don't know, just throwing this out here...

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Re: Aluminum Rod material?

Post by engineguyBill » Mon Feb 12, 2018 11:09 am

Alcoa supplies several of the automotive high performance aluminum rod manufacturers with high quality aerospace aluminum that was developed in conjunction with NASA. Bill Miller (and possibly others) will tell you emphatically that a forged aluminum connecting rod is much stronger than one whittled from billet material. As far as temperature goes, I would imagine that there is a maximum temperature point, at which the aluminum will lose strength and turn into a plastic, then putty. There is such a temperature maximum which will negatively affect any metal whether it is cast iron, steel, titanium, etc., etc. The task at hand is to design the engine so that it does not reach these critical temperatures . . . . . . . .
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Re: Aluminum Rod material?

Post by David Redszus » Mon Feb 12, 2018 1:58 pm

Aluminum can be alloyed with a variety of elements to modify its strength.
Depending on the alloys, it can then be work hardened or heat treated to
further increase its yield strength.

But aluminum yield strength is quite sensitive to elevations in temperature.
As the metal gets hotter, it loses its strength. Not all alloys will loose their
strength by the same amount or at the same temperature.

In addition, under tensile loading, aluminum will change its length as a
function of temperature.

The upper limit of any aluminum is very close to about
450 oF. Beyond that point, it will become considerably weaker.

By knowing strength of aluminum before exposure to heat, and measuring
its strength after exposure, it is possible to determine how high a temperature
the metal was exposed to.

Brinell hardness can be used to measure aluminum hardness. Hardness
correlates very well to tensile strength.

Following is a list of aluminum alloys and their cold (32F) and hot (450F) tensile strength
in KSI (thousand pounds per square inch).

Alloy..........cold.........hot
1100..........23............5
2219 T81.....55...........23
2024 T81.....74...........12
3000..........37...........11
5000..........37...........14
6000..........55............9
7000..........80...........10

As can be seen, aluminum alloys with high cold temperature tensiles do not
have very high hot temperature tensile strengths.

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Re: Aluminum Rod material?

Post by Morgo » Mon Feb 12, 2018 4:34 pm

And remember that aluminium has no stress limit;steel has it at 10 million stress cycles but aluminium lose it's strenght always it is stressed.That's the reason the thousands of aeroplanes stored in Arizona/Texas.. The hours are just done and no one want to be the company whose plane just disintegrate at 10 kilometer..
"when uncomptent order unwilling to do unnecsessary the probablity of failure is high"

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Re: Aluminum Rod material?

Post by SupStk » Mon Feb 12, 2018 7:57 pm

Wonder how much temperature a rod really sees in a drag race or actually any application? Certainly not much over oil temp which would be way under critical limits.
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Re: Aluminum Rod material?

Post by SupStk » Mon Feb 12, 2018 7:59 pm

On the forged rod deal, don't know if I buy the hype. Ever notice they tend to have thicker sectional areas than billet rods? Could it be for necessary strength?
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Re: Aluminum Rod material?

Post by cspeier » Mon Feb 12, 2018 8:38 pm

I know when I worked at GRP/MGP it was a priority material. I'm thinking we even signed a non-disclosure statement.

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Re: Aluminum Rod material?

Post by cgarb » Tue Feb 13, 2018 12:54 am

Its probably only proprietary in the connecting rod world, it will have its own special name, Nastalloy 7000 or something...then in the aerospace industry it has another name.

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Re: Aluminum Rod material?

Post by pdq67 » Tue Feb 13, 2018 5:15 am

Do they make a, "Cermet", aluminum composite rod? If so, how does it hold up?

And just me, but if I wanted to pay for a good rod, it would be made out of 300M heat-treated as needed to be a high strength rod!

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