On Sun, 1 Mar 2020 17:02:42 -0800 (PST), Christopher Tidy
wrote:

Thanks for the responses. Which is more important, the long bake at red heat or the super-slow cooling?

I could put the HSS in a crucible and dial back the power a little each hour using a variac.

Chris

Basically both. The long bake ensures that the "structure" of the
steel is even throughout the steel and the slow cooling ensured that
no "air hardening" for want of a better word, takes place.

I did once anneal a HSS tool bit by heating it for about 8 hours in a
heat treating furnace and than cooling it over about 16 hours in the
oven which had an automatic heat control that was set to reduce the
heat every hour.

But why anneal HSS?
--
cheers,

John B.