"Dar" wrote in message
...
Howdy folks,
Anybody familiar with annealing 0-1 ?. Lately the flat stock I've been
getting is harder than normal , so to test my theory about that being
caused at least significantly by the condition of the steel as opposed
to alloying variances, I annealed a batch of die plates the other
day .
I was right about that and my guess is that the mill is cutting mfg
costs by not fully annealing the stock that the flat-grinders are
being supplied with. According to data from Diehl Steel, the slow
cooling should take place at 35 deg F max . per hour from 1475 deg to
1110 deg, which takes roughly... a whole freakin day !. Regardless of
why the steel is harder than normal, my concern is about degradation
that may occur from the steel spending so much time at elevated
temps. I wrapped my parts in ss foil and that did keep them clean, and
I am assuming that since these are the directions given for annealing,
that it's safe to actually do it; that the steel does maintain it's
"hardenability integrity " through the process of annealing and
subsequent hardening after cold working.

Input?.

Thanks,

DS

The steel should harden with no problem. Some may question whether you'll
have grain growth as a result of the slow cooling, but, IIRC, that shouldn't
be a problem because it's below the transition temperature for the entire
time. Grain growth wouldn't harm hardenability, but it would harm toughness.

In any case, I think anything that happens to the grain is going to be upset
when you heat it above the transition temp again to re-harden it, anyway.
Considering how careful you're being with the annealing, it ought to be OK.

I've hardened plenty of oil-hardening stock but I don't recall ever
annealing it, so I'm speaking from theory rather than experience.

--
Ed Huntress