Anyone have a good heat treat recipe for CPM 3V?

Phillip Patton

Phillip Patton

Knifemaker / Craftsman / Service Provider
Joined
Jul 25, 2005
Messages
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I'm making a knife for a customer out of 3V. I've made a couple in the past, but never was happy with the hardness I got out of it. I did not use cryo. Is that important?

I do have the data sheet for it. Does Crucible's heat treat translate well to knife applications, or should it be done differently?

Thanks in advance,
Phillip
 
The Bos HT is - 1975 F for 30 min, rapid air quench, snap temper 400 F for 2 hours, cryo -280 for 10 hours,triple temper 975 F for 3 hours => 58-60 HRc
 
Mete, how much do you think 3V benefits from the cryo? Would 30 min @ 1975 f with a 400 f snap temper for 2 hours be a good HT for this steel, or would it not be "worth" using this steel without the cryo phase?

Thanks!
 
i have been fond of the cryo over night then low end temper temps for a 61Rc

but like i said its all about the blades use and how hard you want to go
 
Kumdo, you'd really have to try with and without cryo to tell. That is the Bos recipe though I question a "snap" temper of 400 F.Snap temper means tempering to reduce quenching stresses without stabilizing the austenite .Typically that's 300 F.I don't know if his use of the term is incorrect.
The other point is that a temper of 975 F should remove a lot of the RA.Perhaps Bos could explain things. In any case Jerry Hossom is very happy with the results.
 
I am VERY happy with Paul Bos' heat treating of 3V. He's the best.

The key to achieving the proper hardness with 3V is a very FAST quench. If you're doing your own, you'll need to use quench plates to get the temperature to below 1000F (ms start) in less than a minute. If you don't, it won't fully harden, thus the results you've seen. Cryo probably doesn't do as much for 3V as with other steels, since there isn't much retained austenite to begin with.

My favorite steel.
 
Hey Jerry! Long time no "see". Hope you're doing well.

Thanks for all the info, guys. I've had good success (just a couple blades) with quenching 3v on 1.5" aluminum plates... I don't have the hardening & tempering info in front of me but I think it was per Crucible's data sheet. As I recall I was getting 60 Rc, which is good, but I thought I remember that 3v is capable of getting a few points higher and still being extremely tough. I like the idea of being able to get a thinner grind/edge while maintaining durability.
 
Hey John, it's been too long...

The blades I get from Paul are Rc61. I'm not sure you can get it much above that without going above 2000F for hardening which introduces it's own set of problems, like being hard on ovens and needing high temp foil. Rc60/61 should be plenty and gives you good edge retention with amazing toughness. It also takes a wicked edge because of the extremely fine grain structure (~1 micron).
 
I do the same as Mr.Bos, 1975 for 30 min plate quench,cryo overnite and 3 tempers at 400 deg. Get 60-61 consistantly.
Stan
 
SBuzek said:
I do the same as Mr.Bos, 1975 for 30 min plate quench,cryo overnite and 3 tempers at 400 deg. Get 60-61 consistantly.
Stan
Click to expand...

i run a bit hotter but that could jsut be the difference of the kiln readings
im into the 60-61 range too (most being 61 tho)
 
My understanding is that Bos is using a high pressure gas quenchent not air, in an inert atmosphere pressure furnace. Maybe my understanding is wrong but thats what I honestly thought it was.

I would appreciate anyone being able to clarify the facts, thanks very much.
 
You are correct, Nullak. That's what Paul uses, but an oven like his costs about 5 digits. Most here are asking about how to do it with knifemaker level ovens, which are not atmospherically controlled so the blades need to be wrapped in foil to prevent decarburization. Foil impedes cooling so quench plates are used to draw off the heat quickly to effect the fast quench that's needed with some high alloy steels like 3V.
 
Thanks for the input everyone! You've been very helpful.

In the meantime, the customer canceled his order for financial reasons, so I won't be using the information soon. :)
 
Thanks Jerry for the clarification, I understand. The size I need for hobby knife/sword atmosphere ovens are kinda pricey and I've been just sending it to a pro heat treater with my instructions for my heat treat regime. My heat treater has a gas quenched high pressure furnace and cryo facilities.
 
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