--------------------------------------------------
From: "Jim Thomson" <jim.thom@telus.net>
Sent: Saturday, July 10, 2010 5:22 AM
To: "Charlie Gallo" <Charlie@TheGallos.com>
Subject: Re: [TowerTalk] 6061-T8... new alloy
> ## I have been to the same site u just pointed out for other stuff.. and
> they have a lot of error's on there. The big 3 that make al are
> reynolds /alcoa /columbia. And reynolds list 6061 T6 at 40 ksi. All
> other maker's list 6061 T-6 at 35 ksi . All 3 of em list
> 6061- T8 at 45 ksi yield.
>
> ## I used to work in northern bc.. in kitimat.. which has a huge al
> smelter, owned by Alcan.. [ which also owns 14 x more in VE2 land] . A
> ham buddy, VE7DP was a chemical eng there for many years. T-8 is a full
> 10 ksi stronger than T-6....end of story. [yield strength] When T-6
> is actually tested in the lab it's consistently 40 ksi yield. That's
> the number that gets plugged into the various spreadsheets when doing
> ant mech modelling [ like YS 2.15 etc. ] It's usually section modulus
> X yield strength = bending moment. .
>
> u are correct though.... both are the SAME alloy... it's just the temper.
> t-6 is already up there.. and perhaps t-8 is borderline brittle. I'd
> like to know what the diff is between em.... fatigue wise ??
> I like the .120" wall idea... slick. Then they just slide together. ..
> and just a .005" gap all the way around. with .058" el tubing...
> it's a .0045" gap all the way around... so neither are a sloppy fit.
> For boom material, you couldn't ask for anything better... no more
> machining couplers,,, nor turning down the last 6" in a lathe etc. Plus
> it's 10 ksi stronger.....good, cuz it's also .005" thinner too.
>
> Jim VE7RF
>
>
>
> --------------------------------------------------
> From: "Charlie Gallo" <Charlie@TheGallos.com>
> Sent: Friday, July 09, 2010 12:27 PM
> To: "Jim Thomson" <jim.thom@telus.net>
> Cc: <towertalk@contesting.com>
> Subject: Re: [TowerTalk] 6061-T8... new alloy
>
>>
>> On 7/9/2010 Jim Thomson wrote:
>>
>>> I noticed on DX eng's site that they sell boom material, made from
>>> 6061-T8.
>>
>>> Now this T8 version I had not heard of. It's a full 10 ksi stonger
>>> [in yield strength]
>>> VS 6061-T6. That equates to 28.6% stronger..which is nothing to
>>> sneeze at.
>>
>> Huh? Does not compute, as they are both the same alloy, just different
>> tempers
>>
>> The ASM pages for both show the same yield and ultimate strengths, but
>> different hardnesses
>>
>> http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA6061T8
>>
>> http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA6061t6
>>
>> Obviously, with the fact it has the same strength, but different
>> hardnesses, things like elongation at break are different
>> --
>> 73 de KG2V - Charles Gallo
>> Quality Custom Machine-shop work for the radio amateur (sm)
>>
>>
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