Re: [CAD_CAM_EDM_DRO] Re: New guy with questions

I forget where I learned how to heat treat. There are one page explanations
of what temperature produces what color. All of the hardened steels should
be tempered. If this is not done, the tool is too brittle and the hardness
gets you nowhere. The nice thing is that the tempering can be done in your
oven, because they all temper at 400 degrees farenheit.

Here is the years long to learn process for O-1 steel: you take yer welding
torch and crank it up. Since you are hardening things, make it a slightly
carburizing flame. Get someone you don't like to hold the steel object to
be hardened in their bare hands and heat it to a nice glowing red color.
See how long they will hold it before the pain gets too high. Then dunk the
thing into a bucket of oil and swish it around in there. Put out the fire.

Later, after the ambulance leaves with the person you don't like in it,
crank the oven in your kitchen up to 400 degrees. Slap the metal thing in
there and wait until it turns a nice straw color. Straw is a very light
brown. Trust me, unless you are an idiot, you will know when the metal
thing has turned this color. Then turn off the oven and let it cool down,
then sharpen.

As you can see, it is a secret and the illuminati will kill me now that I
have revealed these methods.

> How does oil hardening tool steel work chemically? I know you can heat and
> dunk in oils instead of water for less harsh tempering.

Since the illuminati is going to kill me anyway, I'll let you on to what
happens here as well. These hardening steels have lots of alloying agents in
there. These are small hard things that aren't steel. In it's perfectly
abstract, almost never existing state, steel is a crystal, with perfectly
regular structure throughout. In real life, this perfect crystalline
structure is broken up into grains. In its soft state these grains are
fairly large with well distributed hardening agents. Hardening involves
making the grains smaller and getting the hardening agents to places where
they will do more good.

When you heat up the steel to red hot everything is free to move around, and
the grains get bigger yet and the alloying agents get fairly well
distributed. Then you quench it, and everyone scurries to get a seat before
the bus leaves. The result is very small grain sizes with lots of alloying
agents in the grain boundaries and a lot of residual stress. If you quench
the steel in water, it will cool more quickly than in oil and the grains
will be smaller and thus harder to move around, but it will also be more
brittle. The more time the steel has to cool down the more regular the
structure will be and the result will be a softer metal.

The tempering relieves some of the nasty things you did in the quenching
part.

Hopefully this explanation will not get me drummed out of the Ph.D. core.
Eric