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scherar
04-13-2011, 09:47 PM
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????

Fellhoelter
04-14-2011, 07:17 AM
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.

scherar
04-14-2011, 08:54 AM
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)???????????

Fellhoelter
04-14-2011, 10:47 AM
Are you testing 3 points, and averaging, or just one point?

scherar
04-14-2011, 01:24 PM
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.