You are correct, i left out the full process somehow. I usually just do the one cycle and all is good. When i do the vermiculite cool off i was getting warps and hards spots frequently.
From another forums admin:
I personally would do a full spheroidal annealing on a file:
Heat to about 100F above non-magnetic - 1450-1500F
quench in oil
repeat at just a tad above non-magnetic - 1425-1450F
quench in oil
Heat to just non-magnetic - 1350F
Quench in oil
Heat to just below non-magnetic - 1200F
cool to black heat (900F), and quench
Heat to sub-critical again, cool to black, quench.
What this does is give you a fine grain structure with spheroidal carbides in fine pearlite. When you work the blade it will drill and file easily. When you re-harden the blade, it will start from a good place. If working with simple heat treating tools ( torch, one brick forge, etc.) this is the best approach.