[TheForge] Superquench/hardening power hammer dies

[Bruce Freeman]

Isn't this the whole point of using superquench?  Take mild steel and
bring it up to the hardness of unhardened tool steel (or better)?  Mild
steel is easier to work, generally cheaper (though scrounging makes any
steel pretty cheap), etc.  If those aren't sufficient advantages, then
use the tool steel and be done with it.

Superquench is cheap and easy to make.  The Basic I is not hard to get.
 Try it.  You'll like it.  If there's a question whether it will work on
a large die, try it on a block of mild steel of the appropriate weight,
testing hardness before and after.  (Machineries Handbook probably
describes methods...)  If it hardens sufficiently, go ahead and make the
die.  If not, you're not out much.

BTW, I prefer the name "superquench" so as NOT to confuse the issue. 
That's what it's been called from the get-go.  Note that it's not called
"super-hard quench" or "magic quench" or whatever.  "Super" is just
Latin for
"over , above; besides, beyond, moreover; remaining, over and above".
(http://www.archives.nd.edu/cgi-bin/lookup.pl?stem=super&ending=) 
Superquench provides an action not available in most other quench media,
aside from those made with lye.  Or so Robb Gunter tells us.

Bruce
NJ

>>> osan at netlabs.net 12/29/2004 2:08:09 PM >>>


PlumDon at aol.com wrote:
> The recent superquench discussion has prompted a question: do we
really  need 
> to heat treat our power hammer dies? 

	I certainly don't think open dies need to be heat treated,
assuming 
they are made of a suitable tool steel that will be tough enough for
the 
job of mushing hot metal, but it can be beneficial.  The heat treat 
doesn't have to bring up a high hardness.  4140 is only at something 
like C37 at its highest measured toughness.  This isn't very hard, but

at its peak, 4140 is a very tough steel.

	Closed dies, on the other hand, are much more likely to require
some 
heat treatement in order to ensure reasonable life, especially where
any 
thinner sections and sharp corners may exist.

 > I have some of 4140  and 5160 and do
> not think they have been hardened and tempered.

	But they are nevertheless a world tougher than A36.

> I grind them  back to shape 
> about every six months on my 2x72 Grizzly. Not a REAL heavy user  but
they do see 
> some action. I wonder if heat treating out weighs the gain from 
not.

	A proper heat treat, while not essential is still beneficial
IMO.  It 
leaves the steel in a far better condition than if it is left in an 
annealed state.
>  
> I got the impression from a couple of the posts that many of the
power  
> hammer dies are not hardened. 

	Many are not, from what I've seen.

	I've had the same discussion regarding hot tooling.  Some folks
are of 
the opinion that a punch need not be heat treated because it is being 
driven into hot steel.  I can accept this as valid, especially fro
plain 
tool steels, but I do believe that doing a proper heat treat will leave

the tool in better condition for its intended duties as opposed to 
leaving it in its from-the-mill anneal.  This is especially true of hot

work alloys susch as S7 and H13, as well as high speed steels like M2.

M2 in a fully annealed state, while far tougher than mild steels, is 
still very soft compared to the hardened state.  I have machined 
annealed M2 with hard M2 bits on the lathe with no trouble.  I would
not 
use M2 for top tooling without heat treat if I didn't have to.
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