[TheForge] Superquench/hardening power hammer dies

[Andrew Vida]

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.