Z-TUFF

It would be interesting to do that say 58-59Rc and 61-62Rc comparison with the 15N20. I have not been able to find it again, but I saw a chart that said that the toughest hardness for L6 is like 58, but the steel has a second toughness peak at like 61 where it looked like it was at least 85% as tough, but obviously the extra 3 points of hardness will have a significant effect on abrasion resistance and probably fine edge stability. Those two hardness levels correspond with like 500F and 400F tempers for L6 with moly. I have also heard stories about a couple of other steels, CFV and Elmax, that behave a bit differently when you get into the low 60's and perhaps behave a bit counterintuitively. IIRC, Adam Derosiers said that you don't want to get CFV BELOW say 58-59Rc as it starts acting weird. That would be a temper above 425-435F and I don't know if that is hot enough to cause TME issues.
 
Willie71 said:
I don’t have any s7. I think JT offered to make some samples. If anyone wants to send some to me, I’ll heat treat it to the best of my ability. I did send three conditions of 15n20 to be ground. I think 15n20 performs like a non stainless aeb-l. Run it hard, and it still holds up.

All the steels you sent me have been heat treated, and sent for grinding. I might have to redo the nz3 as I’m not sure my oil quenched it fast enough. I have enough if I have to make new samples.
Click to expand...

Do you have your hardness tester fixed, Warren? If yes, what hrc did you get with NZ3? And with Ultrafort? I’m curious, because Ultrafort on paper can reach 60hrc (and some guys on Messerforum did reached 58/60hrc), but one of my favorite makers “only” reached 57hrc. And he followed the procedure I’ve asked him to use (500C during 6/7 hours, no quench and no cryo). NZ3 also has (on theory) the potential to reach 60hrc, but the makers who use it probably don’t have hrc testers (or don’t care about that).
 
hugofeynman said:
Do you have your hardness tester fixed, Warren? If yes, what hrc did you get with NZ3? And with Ultrafort? I’m curious, because Ultrafort on paper can reach 60hrc (and some guys on Messerforum did reached 58/60hrc), but one of my favorite makers “only” reached 57hrc. And he followed the procedure I’ve asked him to use (500C during 6/7 hours, no quench and no cryo). NZ3 also has (on theory) the potential to reach 60hrc, but the makers who use it probably don’t have hrc testers (or don’t care about that).
Click to expand...

The new indenter came after I sent the samples out. I think I’ll do the nz3 heat treat again, after heating the slow/medium oil I have. I used it Cold when I did the initial sample, and it’s been ringing in my ear since. I followed the procedure to a T, but the oil might have been on the cold side. Nz3 looks a lot like 9260 in composition.

The Ultrafort was heat treated at 1500f, 30 min, air cooled to hand comfortable, then held at 900f for 9h. I followed a page Larrin sent me. According to that page, this should result in Rc59/60, iirc. My “photographic memory” isn’t perfect, but it’s close.
 
Last edited:
Gossman Knives said:
Sounds good Warren. It's new to me so I wanted to start out with that hardness then work up when I can find the time to test it more.
Scott
Click to expand...

One hunter hammered a 0.007” edge through an elk pelvis in 15n20 @Rc62. No damage. It was -10c at that time of year too.
 
jdm61 said:
It would be interesting to do that say 58-59Rc and 61-62Rc comparison with the 15N20. I have not been able to find it again, but I saw a chart that said that the toughest hardness for L6 is like 58, but the steel has a second toughness peak at like 61 where it looked like it was at least 85% as tough, but obviously the extra 3 points of hardness will have a significant effect on abrasion resistance and probably fine edge stability. Those two hardness levels correspond with like 500F and 400F tempers for L6 with moly. I have also heard stories about a couple of other steels, CFV and Elmax, that behave a bit differently when you get into the low 60's and perhaps behave a bit counterintuitively. IIRC, Adam Derosiers said that you don't want to get CFV BELOW say 58-59Rc as it starts acting weird. That would be a temper above 425-435F and I don't know if that is hot enough to cause TME issues.
Click to expand...


I did 15n20 with 1460f austenitizing, 10 min, quench in DT-48, then temper at 250, 300, and 350f. Should be about Rc63/64, Rc61/62, and Rc59/60, according to my testing. I had a sample at 400f, but it was out of spec. If you think it’s important, I’ll redo it.

Edit: you know I can’t leave it alone. I just cut out another sample, and will heat treat next time I use this program in the kiln.

Warren
 
Last edited:
Willie71 said:
The new indenter came after I sent the samples out. I think I’ll do the nz3 heat treat again, after heating the slow/medium oil I have. I used it Cold when I did the initial sample, and it’s been ringing in my ear since. I followed the procedure to a T, but the oil might have been on the cold side. Nz3 looks a lot like 9260 in composition.

The Ultrafort was heat treated at 1500f, 30 min, air cooled to hand comfortable, then held at 900f for 9h. I followed a page Larrin sent me. According to that page, this should result in Rc59/60, iirc. My “photographic memory” isn’t perfect, but it’s close.
Click to expand...

What you used for Ultrafort seems perfect to me! NZ3, if you are not satisfied and don’t mind to heat treat it again, very good!

You’re the man, Warren! Thank you for your incredible generosity heat treating so many steels at your own expense just for the love of science!
 
hugofeynman said:
What you used for Ultrafort seems perfect to me! NZ3, if you are not satisfied and don’t mind to heat treat it again, very good!

You’re the man, Warren! Thank you for your incredible generosity heat treating so many steels at your own expense just for the love of science!
Click to expand...

It’s just my time, and a bit of foil to do this. Chuck @aks is the one who needs to be thanked. He sends me enough steel to try out a knife in each steel. Super generous! I feel very fortunate to be able to contribute!
 
Willie71 said:
It’s just my time, and a bit of foil to do this. Chuck @aks is the one who needs to be thanked. He sends me enough steel to try out a knife in each steel. Super generous! I feel very fortunate to be able to contribute!
Click to expand...

Time is money!:) And a big electric bill, I’m sure! Very nice to have Chuck on board, too!
 
hugofeynman said:
Time is money!:) And a big electric bill, I’m sure! Very nice to have Chuck on board, too!
Click to expand...

The kiln isn’t a big deal. When my bandsaw was down, abrasive disks were killing me though! Even in annealed condition, V4e and rex121 ate through grinding disks to cut out. Since I fixed the bandsaw, no problem!
 
The moly in Champalloy type L6 makes it more resistant to tempering. That is why you have to go to 500F to get 58Rc. From what I have read, you would use a lower temp for non-moly L6 like Carpenter RDS if you wanted 58Rc. It is interesting that 15N20 seems to respond more to tempering that its "parent" steel 1075/1080.
Willie71 said:
I did 15n20 with 1460f austenitizing, 10 min, quench in DT-48, then temper at 250, 300, and 350f. Should be about Rc63/64, Rc61/62, and Rc59/60, according to my testing. I had a sample at 400f, but it was out of spec. If you think it’s important, I’ll redo it.

Edit: you know I can’t leave it alone. I just cut out another sample, and will heat treat next time I use this program in the kiln.

Warren
Click to expand...
 
jdm61 said:
The moly in Champalloy type L6 makes it more resistant to tempering. That is why you have to go to 500F to get 58Rc. From what I have read, you would use a lower temp for non-moly L6 like Carpenter RDS if you wanted 58Rc. It is interesting that 15N20 seems to respond more to tempering that its "parent" steel 1075/1080.
Click to expand...

I think it’s the nickel. Nickel lowers the requires aust temp. That’s why 1460, rather than 1475/1500f. No sure how it affects tempering temp though. Larrin? Help?
 
jdm61 said:
I am wondering how tough this Z Tuff will be to finish. I have no problem with 3V at 60-61 on a big hunter sized blade, but I am used to big knives in W2 and CFV so I may be a bit of a masochist. For me, the heavy lifting part of of hand sanding is done with 320 and 400 grit EDM stones.
Click to expand...
I’ve been finishing mine with a fine scotchbright! That’s all I’ve gone so far.
 
Ok, after cryo at 1925f, I got Rc63/64, pre temper.

I’ll try 1975, and 2025f, and see if there is extra in there. We’re pushing outside the design parameters now. I’m tempering at 300f, and will do another sample at 400f.
 
Willie71 said:
Ok, after cryo at 1925f, I got Rc63/64, pre temper.

I’ll try 1975, and 2025f, and see if there is extra in there. We’re pushing outside the design parameters now. I’m tempering at 300f, and will do another sample at 400f.
Click to expand...
Play by play! Love it!
 
Z-tuff, 1250, 10 min, 1550f 10 min, 1925f, 30 min, plate quench, cryo for 1h, tempered at 300f 2h, came out at Rc60/61. I did 10 Rc tests, and all were between Rc60, and Rc61. I’ll see what tempering at 400f gives us.
 
Willie71 said:
I think it’s the nickel. Nickel lowers the requires aust temp. That’s why 1460, rather than 1475/1500f. No sure how it affects tempering temp though. Larrin? Help?
Click to expand...
One of you is talking about tempering and the other austenitizing. More alloy does improve tempering resistance. Nickel reduces austenite transformation temperatures.
 
You must log in or register to reply here.
Back
Top