On 11/25/2010 Jim Thomson wrote:
> ## My guess is, instead of using 6061-T6 or 6063-T832, they have gone
> to a cheap alloy, like 3003, which comes in various grades of hardness,
> listed
> as H-0 to H-14. H-0 is only 6 ksi yield, and the strongest is no
> match for
> 6061-T6 or 6063-T832.
What is interesting is "yield strength" vs ultimate strength - various tempers
WILL have different yield strengths - "Yield strength" is the amount of force
to cause the material to BEND and NOT return to it's original shape - "Ultimate
strength" is the amount of force needed to BREAK the material
Now, IF the alloy is actually the same (hint, a lot of the Al that is sold is
NOT the same for the different tempers, and some can't be tempered after
alloying) - the "Ultimate strength" doesn't change - Note however, the Alcoa
data sheets DO tend to guarantee a higher ultimate strength for higher tempers
(not all - lets talk 6061 - they guarantee the same minimum for T0 and T4 -
and of course T6 and T6511 are the same - in fact I often see t651(1) sub'd for
T6)
I know you take say a piece of 0-1 steel - the ultimate strength is totally
unchanged by hardening - what IS strange - say you go just under yield strength
- the hardened steel will flex a LOT less that the unhardened, and still
return, but they break at the same point
If I see my wife's uncle this holiday season, I'll ask him to write something
up - he's a (now retired) PhD in materials science who specializes in Alloys
(mostly Fe Alloys), and is considered one of the top guys in the field (as in
international award winning)
--
73 de KG2V - Charles Gallo
Quality Custom Machine-shop work for the radio amateur (sm)
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