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(Time Traveler) wrote in news:17373-42729A16-424
@storefull-3135.bay.webtv.net:

Looking at the posts on metal hardening I was wondering what are the
dynamics of oil versus water hardening.What is happening to the metal
using one or the other?I assume water brings down the temperature
quicker but have no empirical knowledge on the subject.

The quenching determines, to a large degree, what the hardness of a
particular material will be. The biggest factor is delta T, or the change
in temperature over time. The higher the delta T, the harder the
material, within it's hardening range. Since water has the (AFAIK) most
efficient transfer of heat, using water will make Delta T large. Oil
doesn't wick away heat as fast, so Delta T will be smaller over the same
time period.
Water will also cause the surface to cool much faster than the inside,
resulting in a somewhat stratified hardening of the material. Oil
quenching narrows the temperature gap between the inside and outside of
the material, allowing for a more even hardening as you go deeper into
the material.

--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

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