Emmett <emmett.shear@[EMAIL PROTECTED]
> wrote:
> Is there something special about iron that makes it the only metal
> you can substantially improve by carburizing?
Iron is the only one that changes crystal pattern in such a way to
make room for carbon to fit into the newly formed "open spaces" when
it's heated and then when the iron is cooled will trap(!) the little
suckers.
And it isn't just carbon that fits into those spaces, so does boron,
phosphorus and nitrogen. Case hardening compounds usually have all
those elements avaiable BTW. :)
Iron when heated to a certain temperature switiches from...
"body centered cubic" to the "face centered cubic" crystal pattern.
When iron is hot enough to switch to FCC it glows orange hot in the
dark and you can feel the heat on your face. ;) (face centerd cubic)
Both crystal patterns, BCC and FCC have the same density tho. :)
The atoms rearrange very slightly but the "open spaces" are
distributed differently, see? ...that's all an atom the size
of carbon (et.al.) need to get sucked into the open spaces.
Ok, got that? :)
Next, picture a cube made from tinker toys where all the sticks are
the same length. It "gives" when pressed from odd angles. Take one
stick out and put in the next longer stick. The cube is now under
tension (since you hammered it together?;) and doesn't give so easy.
That's symbolizes the distortion created by a trapped C, B, P or N
when the iron returns to room temperature and its usual BCC
configuration.
Got that one too? ;)
> I know this question is probably absurdly clueless...
But a cool one anyway. :)
> Anyone know the answer, or where to read up on it?
www.amazon.com
"Metallurgy Theory and Practice" by Dell K. Allen
Alvin in AZ
ps- I'm the dumbest guy on s.e.m and so, best qualified
to answer the clueless questions. :)
pps- BBC iron is magnetic and FCC iron ain't, so, the iron
tells you when it's "hot enough".
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