Recommend me an Aus temp for 3v please

rodriguezryan14

rodriguezryan14

Joined
Jan 6, 2023
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208
So I’m trying something a little different, and I’m just looking for recommendations. I’m shooting for 58rc on cpm3v, reason is for a bigger knife. I usually run my blades at 1950, 30 minute soak, plate quench, cryo and triple temper at 400 for about 61 rc. Has anyone austenitized at 1900-1925? I would expect to gain some more toughness with the lower aus temps. That’s the goal! The problem is, I’m not sure if the blade I’m building will even fit in my deware, so I may end up using a high temper instead! I’m thinking if worse case, 1900-1925, 40 minute soak, plate quench, then triple temper at 1000 to 1025. What are your thoughts?
 
I tried 1925 aus temp, 40 minute soak, overnight cryo and triple temper at 400 for 58-59 rc. I should gain a nice amount of toughness for this style of knife. Most of my 3v blades are usually over 60 rc. This got me where I wanted. I usually austenitize at 1950-1975. I’ve never tried lower. I think I can do 1900 for an even tougher blade if needed.
 
As seedy lot says, you can also do the high range temper for a big gain in toughness. Larrin's book is very helpful on designing a HT regeim.
 
I do have larrins book. I need to read it more I think. Lol. I do find the high temper a benefit in z-tuff. The blades are insanely tough. But I haven’t messed with it much for 3v. If I could find the time, more experimenting needs to be done. Thanks guys!! I appreciate it
 
rodriguezryan14 said:
I do have larrins book. I need to read it more I think. Lol. I do find the high temper a benefit in z-tuff. The blades are insanely tough. But I haven’t messed with it much for 3v. If I could find the time, more experimenting needs to be done. Thanks guys!! I appreciate it
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I used Larrin's data to choose a heat treatment for a recent 3V blade. It turned out fine. The info is in the back of the book. I found the first chart particularly useful. Since I don't have LN and only have access to dry ice, I chose 1950F and 350F. I figured I'd probably get Rockwell 59-60 with this, maybe a little less, maybe a little more. I guessed that the lower Aust. temp would give less RA. Just a guess, though. If I had LN I'd have probably bumped the numbers up a little bit.
 
Impact toughness is significantly worse with the high range tempers. You lose a lot of impact toughness for a small gain in wear resistance. I would stay way from the upper temper range, especially on a big knife.
 
Stuart Davenport Knives said:
Impact toughness is significantly worse with the high range tempers. You lose a lot of impact toughness for a small gain in wear resistance. I would stay way from the upper temper range, especially on a big knife.
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You lose that fine edge stability, so you would get more rolls and possible edge damage! Basically losing edge strength!! But I wonder, has anyone tested for sheer durability? I’ve read somewhere that you can gain overall toughness! In my ztuff testing, I lost edge strength, but gained raw toughness with the high vs low temper, Like break in half toughness! I’ve never tested 3v like that. It’s something I think I need to do. Time is always against me these days!! When I have the time, I’m planning on testing this more myself, along with A8 mod. I’ve been working with that steel a lot lately!! Basically looking for a perfect heat treat for different applications! The knife I made was a variation of a wsk tracker knife that I’ll be using for some wilderness horse pack in hunts! My goal is something as durable as possible that would still break down an elk easily! 3v fits the bill, the question is the heat treat!! My knife tested at 59 rc with the low temper protocol! I also built one in A8 mod, a slightly smaller version with a high temper that I’m testing right now! So far I’m very impressed with the heat treat. Everyone recommends the low temper, similar to 3v heat treat on that steel too. But so far the high temper has held up great! Time will tell though!
 
HPD said:
I used Larrin's data to choose a heat treatment for a recent 3V blade. It turned out fine. The info is in the back of the book. I found the first chart particularly useful. Since I don't have LN and only have access to dry ice, I chose 1950F and 350F. I figured I'd probably get Rockwell 59-60 with this, maybe a little less, maybe a little more. I guessed that the lower Aust. temp would give less RA. Just a guess, though. If I had LN I'd have probably bumped the numbers up a little bit.
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You should be around 59-60 if you got a quick quench! Dry ice is plenty sufficient for 3v in the absence of ln2. I was originally using 1950 40 minute soak, frozen plate quench, into the freezer for 10 minutes, cryo, and triple temper at 400 for 61rc consistently! You can still go lower on your aus temp. I tried 1925 for a 40 minute soak, next I’ll be trying 1900. 1925 got me 58-59 rc. 57-58 is the sweet spot for 3v as far as toughness goes. But of course other factors come into play too!! Crucible shows 1875 on their data sheets for the lowest austenitizing temps! I’m not sure id go that low. As quenched hardness is listed at around 58, after temper is around 55-56 I think!
 
I am not sure if you're saying that you lose fine edge stability by using the low temp tempers, or using the high temp tempers.

But the fact of the matter is you LOSE fine edge stability by using the high temp tempers. You rob the martensite of carbon in order to form the temper carbides, thus weakening the edge apex. You gain a little bit of wear resistance when the carbides are formed, but at the expense of impact toughness and fine edge stability.

Nathan Carothers has experimented with high vs low tempers on D2 and especially 3V and his results are very very clear. This is one of the main points of the "Delta heat treat" protocol.
 
Stuart Davenport Knives said:
I am not sure if you're saying that you lose fine edge stability by using the low temp tempers, or using the high temp tempers.

But the fact of the matter is you LOSE fine edge stability by using the high temp tempers. You rob the martensite of carbon in order to form the temper carbides, thus weakening the edge apex. You gain a little bit of wear resistance when the carbides are formed, but at the expense of impact toughness and fine edge stability.

Nathan Carothers has experimented with high vs low tempers on D2 and especially 3V and his results are very very clear. This is one of the main points of the "Delta heat treat" protocol.
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Yes, I lost that fine edge stability and edge strength with the high temper on ztuff. But I’m curious if you can gain overall blade toughness with the high temper with 3v like I did with ztuff! I need to do some comparisons with both heat treats. I just haven’t had time! Same with A8 mod! If I can gain overall toughness skipping cryo, that would be a benefit for certain applications! Besides, cryo has really jumped in price where I get it!! 90 bucks to fill my 10l deware! And I haven’t been building enough blades to really justify the cost!
I’ve seen Nate’s tests, and that’s why I’ve been using that kind of heat treat. I’ve just never tested 3v with a high temper, or lower aus temp! So far the blade I heat treated has been really impressive! But more testing is needed!!
 
rodriguezryan14 said:
You should be around 59-60 if you got a quick quench! Dry ice is plenty sufficient for 3v in the absence of ln2. I was originally using 1950 40 minute soak, frozen plate quench, into the freezer for 10 minutes, cryo, and triple temper at 400 for 61rc consistently! You can still go lower on your aus temp. I tried 1925 for a 40 minute soak, next I’ll be trying 1900. 1925 got me 58-59 rc. 57-58 is the sweet spot for 3v as far as toughness goes. But of course other factors come into play too!! Crucible shows 1875 on their data sheets for the lowest austenitizing temps! I’m not sure id go that low. As quenched hardness is listed at around 58, after temper is around 55-56 I think!
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It was a quick quench. The blade being thin helped. I plan on trying the frozen plate trick tomorrow on another 3V blade. I read a post by Nathan Carothers saying he doesn't recommend tempering below 400, but he didn't say why. Maybe it's due to the greater potential of destroying the temper during post-HT grinding. I'm usually pretty careful, slowing the belt way down and dunking in water after each pass. If there's any other reason not to temper below 400 I'd like to know.
 
Seedy Lot said:
I would select fine edge stability any day over how much force it takes to break in a vise.

Easy to use thicker steel thickness to add a bunch more toughness.
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I agree for the most part, but most hunters and guides I build knives for, want thin and tough blades. My opinion, is that there’s room for both heat treat’s depending on what someone is wanting! Also, cryo is really expensive here now. It never was. So if I can save me some money and get away with a high temper, I’d be all for it! All user dependent I think!
 
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HPD said:
It was a quick quench. The blade being thin helped. I plan on trying the frozen plate trick tomorrow on another 3V blade. I read a post by Nathan Carothers saying he doesn't recommend tempering below 400, but he didn't say why. Maybe it's due to the greater potential of destroying the temper during post-HT grinding. I'm usually pretty careful, slowing the belt way down and dunking in water after each pass. If there's any other reason not to temper below 400 I'd like to know.
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I’ve been told frozen plates don’t help much. But it’s how I started when I got into this, so I just continue doing what’s worked for me so far. You can temper below 400, but you would probably be better off increasing your austenizing temperature instead, if you’re looking for more hardness. You can go all the way up to 2000 degrees if you’re using cryo! So if you want higher rc, rather than reducing temper try increasing your aus temp. Make some coupons if you have time! My time is extremely limited, I get in my shop a couple days a month. So it’s hard for me to test extensively!
 
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