Temper & Hardness
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Joined: January 02, 2005
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Temper & Hardness
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Posted on Wed Feb 02, 2005 9:51 pm
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I did some searches and hit the F.A.Q. and couldn't find the info I was looking for.

I understand what temper is and how the hardness is referred to (dead soft, 1/4 hard, 1/2 hard, etc.).

What I want to know is if a 1/2 hard (for example) temper in one metal, stainless for example, will be the same hardness as a 1/2 hard aluminum or if these values are all relative to the material that you're talking about. I can see a viable arguement for either way of doing it - but just don't know the rule of it.

I'm probably going to be getting some 3/4 hard aluminum and steel and didn't know if I should expect them to be the same or different hardnesses relative to each other.

Thanks Smile


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Posted on Thu Feb 03, 2005 12:28 am
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They will be different. Steel will always be stronger than aluminum, in the same sizes. e.g. wire- and inner- diameter. For more specific answers, let's wait until Hatman or one of the other metalurgy guru's get to this. :>


CyberKender Esquire
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Joined: January 02, 2005
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Posted on Thu Feb 03, 2005 12:30 am
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Ok, that's what I was thinking and just wanted to be sure. Thanks!

Oh - and what is that picture of in your avatar?

First impression is that it's Orco (from He-Man) with a big scythe on top of a giant peach...

(nobody ever said I was normal)


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Posted on Thu Feb 03, 2005 3:26 pm
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So I've become a metallurgy guru now, huh? I'll try not to let you down, Cyberkender.

This is the sort of thing I like to explain with charts and graphs and all sorts of props, so forgive me if I don't make myself clear, or if I get long-winded. The short and easy answer is that, as Cyberkender said, and as you supected, the hardness ratings for each material are on a scale from dead soft to full hard based on on the material. You can't make a material any softer than a certain value, or any harder than a certain value based on what that material is. If you do some research, you can figure out what values of hardness you need to get in two different materials so they behave in a similar fashion. Example: if you get 3/4 hard brass in a certain alloy it will have the same yield strength as 1/4 hard stainless in a certian alloy. I have done this before. BUT the caveat is that only the yield strength is the same. The ultimate strength is still the same unique for each material AND DOES NOT CHANGE AS YOU HARDEN OR SOFTEN the material. Similarly, the young's modulus does not change and remains constant for each unigue material.

WHAT THE HECK DOES THAT MEAN?

a couple of definitions (I'll try to keep them non-technical):

Yield Strength - the amoubt of force you need to apply to a material to make a permanent bend.

Ultimate strenth - the amount of force you need to apply to break a material

Young's modulus - the ratio of how much a material bends versus how much force you have applied.

That means that even if you get the yield strength for 2 materials to be the same, say brass and stainless, if you apply the same force to both, the brass will bend farther than the stainless. But they'll both spring back as long as you have applied less force than the yield strengh... if you apply more force than the yield strength, then the object won;t spring back all the way.

I hope that helps.

Joined: January 02, 2005
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Posted on Thu Feb 03, 2005 4:36 pm
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That's very helpful - thank you!

My big question was "is hardness a fixed scale for all materials or is it relative to each?" - which is nice to know "for sure".

The other stuff is a very nice bonus Smile


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Joined: April 20, 2004
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Posted on Thu Feb 03, 2005 6:46 pm
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You just proved you are compared to me, Hatman. :>

MikeB: Nope, it's not Orko. It's part of the picture on the Le Petit Mort picture from the XXXenophile CCG.


CyberKender Esquire
RenMerc and Rogue Journeyman Bodice-ripper
Punslinger-at-Large Fnord! The Brass Kender
Brute Squad, Stealth Division
Apparently Appointed Mayor of There
Enough to make a grown man cry.

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