Advice from Plate Quenchers

scherar

Well-Known Member
I have had pretty good luck so far plate quenching (1" aluminum) CPM 154, but just recently had some bad luck. I did two blades per batch last night and tonight. One blade came out fully hard, and the other came out a few points low. This happened both nights. Can anyone help. Here is what I did:
-My usualy HT recipe, blades wrapped in foil.
-Pull out, quench in between aluminum plates, shoot compressed air in between plates
-I started cooling my plates in ice water (towel dry) before and in between quenches.
-After the first night, I put slightly thinner shims on the bottom plate to prevent rocking of top plate.

The first night, the second blade came out harder (it was only profiled though). Tonight, I am not sure which one came out harder because they were exactly the same and had bevels ground.

Any ideas????
 
Not enough time at temperature?

CPM 154 will air cool, so you should get a hard blade even with no contact on your plate, but you should only get 1-2 points different between air or plate quench.
 
My final soak is for 30 minutes. After I remove the first blade, the second one sits at least another 4-5 minutes to get back up to temp after opening the door. I am not sure which one hardened well last night, the first or second. The night before it was the second one (although it was only profiled).

I have heard of people just air cooling CPM 154, so I didn't think that there would be an issue when put between plates and using compressed air. I thought it would just make it "that much" faster.

Something weird though, I re-tested the blade that didn't harden all the way this morning and I got results of 60.5-62. This was after sitting over night. I went ahead and tempered it and I will test this afternoon. Is it possible to finish hardening over night (no cryo)???????????
 
I am testing at least three different spots. When I test oil quenching steels, I test as close to the front as I can that will be hidden by a bolster or the handle (I don't fully quench those type of blades).
When I test stainless (plate quench), I test most up close to the blade and a couple on the tang.
 
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