Dude, I just went through that exact song and dance myself. I sent a one by one inch chunk of it to a guy off of the knife-list and he sent me back a chemical analysis of the steel. Turns out it's not an exact match for any of the usual tool steels, the closest was A2 with a little extra chromium. The anneal cycle for A2 is quite difficult and requires a programmable heat treat oven with temp controls, stainless foil to keep it from scaling away to nothing, and about 18 hours of oven time.
Most planer blades I've run across are not marked with steel type or even manufacturer. If (big if) you can verify with the people you're getting them from who they order them from, you might be able to get a steel composition from the manufacturer, but there is no guarentee it's the same from one lot to the next.
If you have a pretty good idea that some of the blades you are getting are from the same batch, you could get an analysis done and send them out to Paul or Rob for annealing, then they would grind up quite nicely, but....as with most salvage steel, it's a crapshoot.
One last note, as far as I know, none of the air hardening or stainless steels can be annealed just by heating to critical and slow cooling. YMMY
Good Luck
James
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Those who are willing to trade freedom for security deserve neither, and in the end, seldom retain them!
