NITRO-V heat treat

Kevin McGovern

Kevin McGovern

Joined
Jul 31, 2015
Messages
3,118
So I've been using Nitro-V for a while now. In the past, using AEB-L, I have forgone sub zero for two batches of drop point hunters, that I wanted around 58-59HRC. It worked out fine. Be advised, that Nitro-V, though very similar to AEB-L, will not harden without a sub zero quench ( DI or LN) just a heads up.
 
not sure if you've seen but Simple Little Life on YouTube has a video showing his heat treat process of Nitro V and claims he gets great results without a sub zero quench.. can this be true?
 
Kevin, would you mind elaborating on "will not harden"? I take that to mean that it does not harden AT ALL, in which case something is wrong somewhere. It is basically 14c28n, and according to Sandvick's data about 14c28n, it should reach 59HRC (after 350F tempers) without any sub zero, 60HRC with a -5°F sub zero, and 62HRC with a -95° sub zero.
 
I am also curious about this. I assumed being close to AEB-L, that a cryo would be very beneficial, but the info directly from my supplier states that while it does benefit, it’s not required to subzero. I have not done any HT on Nitro yet, but I know AEB-L is like a noodle until it goes into the subzero. When I tested Without cryo, my Aebl does harden up after tempering, but not as hard as I want and not as hard as I get with the subzero steps.
 
It's a little complicated, so I'll do my best.

I follow the D DevinT method for both Nitro-V and AEB-L. 20 minute soak at 1725, plate quench. 1950, Plate quench, dry ice slurry. During my last run, I had a problem with my oven and my coils broke. (a packet fell over into them and fused to the element, when i pulled that packet, the coil came with it. Fun times playing with a 2000 degree slinky ensued). I fixed my oven and went to do the final heat about a week later. The first run had been presoaked and plate quenched and were NOT the knives in the oven when if failed. I did a 12 minute soak at 1950 and plate quenched. Since I didn't have any DI and the target for these was 58-59 anyway, i figured no big deal. I tested them after one hour temper at 325. they read in the 40s. I contacted Ed Braun, cause i have him on speed dial for such shenanigans. He informed me that the added vanadium and nitrogen makes sub zero a critical step for Nitro-V. With all the crazy that went on for these few blades, I guess anything could have happened. I also tested my Thermocouple and it's fine.
 
Robert Erickson said:
To respond to Grayzer86:
There was a great recent discussion on this topic: https://www.bladeforums.com/threads/liquid-nitrogen-vs-dry-ice.1540810/
IIRC the main reason for cryo (LN) is that it reduces RA and creates a fine "eta" carbide which ads to strengthening and hardening. So it seems that without it we are leaving performance on the table.
Click to expand...
I wasn't expecting the same performance. Perhaps a point or two less hardness. I DIDN'T expect it to come out in the 40s. I know AEB-L would not have.
 
Kevin McGovern said:
I wasn't expecting the same performance. Perhaps a point or two less hardness. I DIDN'T expect it to come out in the 40s. I know AEB-L would not have.
Click to expand...
Hmm that's kind of weird that it didn't harden up at all being so close to AEB-L. So I guess cryo it is :thumbsup:
 
Kevin McGovern said:
I wasn't expecting the same performance. Perhaps a point or two less hardness. I DIDN'T expect it to come out in the 40s. I know AEB-L would not have.
Click to expand...

If I'm not mistaken this is pretty much like 14C28N, which I've used a lot of. If I heat treat it and omit the dry ice or LN2 I get it around 59-60 HRC. So your results definitely looks strange.
 
currenthill said:
If I'm not mistaken this is pretty much like 14C28N, which I've used a lot of. If I heat treat it and omit the dry ice or LN2 I get it around 59-60 HRC. So your results definitely looks strange.
Click to expand...
having used a lot of AEB-L, I was very surprised as well.
 
one additional piece of information I forgot to include. I find that AEB-L seems to attract a magnet equally well, hardened or annealed. The blades in question are noticeably less attracted to a magnet, to the point where I can't hold them on a magnet to surface grind them.
 
Kevin McGovern said:
one additional piece of information I forgot to include. I find that AEB-L seems to attract a magnet equally well, hardened or annealed. The blades in question are noticeably less attracted to a magnet, to the point where I can't hold them on a magnet to surface grind them.
Click to expand...

That’s very interesting. So far I haven’t seen any upside to Nitro-V compared to AEB-L.
Thanks for sharing your experience.
 
You are supposedly able to get a point or two higher. I haven't pushed it that far. I will say that it is noticeably more corrosion resistant. Not that I was unhappy with the corrosion resistance of AEB-L. I have a bunch of Nitro-V, So I'll keep using it. I havn't had any issues except for this one, which normally, wouldn't be an issue.
 
Kevin McGovern said:
one additional piece of information I forgot to include. I find that AEB-L seems to attract a magnet equally well, hardened or annealed. The blades in question are noticeably less attracted to a magnet, to the point where I can't hold them on a magnet to surface grind them.
Click to expand...

That means that there is lots of retained austenite which confirms your original assessment that it needs some kind of sub-zero quench.

Hoss
 
I'm sure that most of you know this but Nitrogen is a austenite former. It can be a problem when welding stainless. I have a reasonable knowledge of how metal works for welding but still very fuzzy when it comes to knives.

Is that something that would change the heat treatment plan?
 
You must log in or register to reply here.
Back
Top