Ideal hardness for CPM 3V?

flatgrinder

flatgrinder

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Dec 20, 2005
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Hi, I'm in the process of making a camp knife (10" blade) out of CPM 3V, what's the ideal hardness for the best balance between toughness and edge retention? And what tempering temperature do you use?

Thanks! :thumbup:
 
Absolutly the very best out there for multi use knife. You will need to consider how much abuse it will be subjected to, I double quench at 2000 deg. with frozen plates, temper at 1000 deg. , pack in dry ice overnight and temper 2 more times at 1000 deg, set the edge to 12-15 degrees convex. I think I am getting about 62 rc. I do not abuse a cutting knife, I like a very sharp edge that holds well and this works for me. Go to crucible's site and study their charts to make your own determination as to what meets your needs. You must get temp down below 1000 deg very fast with this steel. A interupted oil quench works very well to, but getting it out of wrap and into oil fast enough is a challange, Thats why I double quench and do not remove it from the foil warp.
http://www.crucibleservice.com/datash/ds3Vv5b.pdf?CFID=856627&CFTOKEN=51031604

Leon Pugh
 
leon, could you please explain this "double quench at 2000 deg."? Are you saying you take it to 2000-quench, take it to 2000 and quench a second time, or what?
Thanks,
 
for me its
preheat 1550 7 min
full ramp heat to 2050 for 20 min
plate quench (1x6x18 Al plates)
Ln over night
temper 3x 2 hours 1000
this is more less as per crucible data sheet there info is great
i will say thjis the steel doent need to be kept "soft" to be storng 60-61 Rc will still take a lot of abuse
ooo and btw that is for 3/16 stock

and from what i have read and talk to crucible about leon if your goingt ot "double quench" just hold the 2000 temp longer that is if your kiln will do it it will do the same thing as your heat treat
remember its time at temp without over heating that counts
 
Mr. Harner, you seem to understand this "double quench at 2000 degrees", could you explain it and the reason for it to me?
Thanks,
 
Butch I don't intend for this to sound like a putdown, after reading my thoughts let me know what you think, I see no harm in this process, only benifits and I want all the hardnes I can get. I don't think he does, I may be the only person that double quenches this steel, I am trying to achieve all the hardness I can get with out causing grain size to grow. So I prefer not to austenitize over 2000, interrupeted oil quenching get the temp down fast and does a good job but there is alot of clean up needed to the blade afterwards. Quenching with the blade wrapped in stainless foil has
another problem (though blades come out the wrap in near perfect condition), I taper the tangs and use a distal taper, therefore the blades do not have complete contact with the quench plates, rocking the plates while quenching does help some, butt it does slow down the cooling rate. Unlike some steels 3V take a long period of time to soften it at a very gradual temp drop (25 deg per hour). I found that if you rewrap it and repeat the process that it will come out a little harder. Call it a security blanket if you will, But I swear it works. Soaking it longer will not do anything to resolve the cooling time issue. Yes I do quench with the wrappers on. It goes from the point of barley making a file scratch on a edge to the file skating with no mark.

Leon Pugh
 
Multiple quenches on air hardening steels causes a duplex grain.
 
ooo i dont have a problem heck i know there is at least one person running 3v at temps up and over 2100 (getttign higher Rc readings with a tester)
i agree about the oil quench its fast but messy and fumbling around with fiol packs gettign the blade out is no fun
guess it sorta is we all do things a little different hell my kiln does not read the same as yours even it its the same make and model
if i was going to go with 62-63 RC i would just step up to 10v as thats the range 10v seem to be made for
looking at the charts 3v impact toughness drops way off at over 61 rc
might you be gettingthe same spec of 61 like me and the files are making you think its higher maybe maybe not you didnt say if you had a rc tester back up
now and then i take a few test blades to the tool and die shop in town and make sure my batches are still where they are to be as my kiln egts older i will have to replace the pryo cause it can staert to read off temp and mess up my treating
and the long short is can we ageree that 60-61 RC is about where 3v seems to have its sweet spot for most our knife needs
however we get it there:D
 
Stag & Steel said:
Mr. Harner, you seem to understand this "double quench at 2000 degrees", could you explain it and the reason for it to me?
Thanks,
Click to expand...

hahah nope i dont understand it less your doing things with out a kiln
my thought is that it works for some steels better then others but thats because of not have a good soak time
bringing a steel up to to aust. temp a few time is said to let more of the carbon get in to solution insteat of a full soak
the idea being that 3x quench from aust temp if you can hold the temp like 5 min
3x 5 min = 15 min soak right :foot:
well sorta
kevin and mete need to drop in her and help me out alittle as there is way too much that i still dont know all about
 
Thanks Lloyd, I have been seeing this term used a few times lately and was struggling with the understanding it.
 
More than one of you seem to be very confused , and refuse to understand that each steel is different !! What may work very well for a simple carbon steel may not work at all for a complex stainless steel !!!!.There even seems to be some paranoia about grain growth . For a steel like CPM 3V to be heat treated properly the carbides must be dissolved and that takes time , maybe 25-30 minutes .Without that you just won't get the properties that the steel offers .These steels have things like vanadium which retard grain growth...You like CPM 3V ?? when you heat treat it properly you'll get the full performance and like it a whole lot more !
 
If you follow the recommended heat treatment of 3V you'll never go wrong. They give example heat treatments for 58 Rc, 60 Rc, and 62 Rc. Try all three for different applications. I'd say for most applications, the toughness you get at 62 Rc is plenty, which gives you the greatest strength and edge retention from higher hardness.
 
thank you mete
larrin
fixed blades i like to run 60-61
a folder im goingto try getting 62 or so to see how it works out
it seems that folders done see the abuse you may get with a fixed blade
 
Mete you are not reading my posts carfully and are jumping to conclusions. I would like talk about this more, but first you need to understand why I am double quenching, furthemore I am a stickler for following manfactures recomendations first to develope base line information. ThenI experiment to see what improvements can be made. KEY POINT MY DOUBLE QUENCHED 3V & S30V BLADE OUTPERFORM SINGLE QUENCHED BLADES UNER THE CONDITIONS THAT I USE THEM. Don't make the statement that its wrong without something to back it up, use, testing, data etc. How do new ideas get developed, if it did not show me merit I would have never done it second time. Please elaborate on your feelings, othewise your critiscism will not be taken seriously. I am not trying to put you down you know more technical information about steel than I ever will, but it appears to me it flat works. I am a open minded person that will never be happy unless I am trying to improve anything I do.

Thank You Leon Pugh
 
Mr. Pugh, what is your hold time at 2000F each cycle? Sorry if I missed it in your comments...
Thanks! :)
 
Sorry i forgot to post it, 20 minutes. I have to get back to right now, but i just had a intresting conversation with crucible about this. I will post more on that conversation to night.
I due very much appreciate constructive critiscism and others thoughts on this matter.

Leon Pugh
 
Leon, Maybe I can shed some light on this or maybe even add to the confusion. When S90V first came out (420V) I had a lot of trouble getting a hardness over about 58 as quenched. My furnacne controller would not go over 2000. S90V needs about 2100 to get a good consistent 62 or 63 as quenched. At that time I was double quenching at 2000 and was able to get the 62 I wanted. The blades were tough and had exccellent edge holding at least with my testing at that time. I still have a blade of my own that I use that I used this technique to heat treat. I was concerned about this and aske one of the Crucible guys what he thought. He said with the CPM steels it is hard to blow the grains and that I was probably ok with this method, as long as I was getting the results I wanted. There is really no way to tell with out a met lab to take a look at all this. I eventually built a new furncance that would go to 2200 so don't need do this any more. Is it good practice? probably not but sometimes you have to inovate to get what you want If you want to check hardness on your blades send me a sample and I will let you know what it is.. Phil
 
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