Does anyone know how to heat treat Admiral's L-6?

Phillip Patton

Phillip Patton

Knifemaker / Craftsman / Service Provider
Joined
Jul 25, 2005
Messages
5,362
What I'd like to know is, is it deep hardening or shallow hardening? Does it heat treat like 1075, or what? The chemistry Admiral lists for it is the same as Crucibles L-6, but they are quite obviously NOT the same thing.
????
I know Timken and Carpenter also make L-6. I can probably get dta sheets from both of them. What's your guess as to who makes it?
 
C'mon, surely someone out there is using this stuff with some success.
I did get the Timken Latrobe data sheet, which does list a different chemistry than Crucibles, so if nobody pitches in here I'll just go with that.
I couldn't find anything about L-6 anywhere on Carpenters website.
 
Just before I started working with 52100 I was working with L-6. It responded very well to low temp forging, multiple quench with Texaco Type A and all the same stuff I do with 52100, the blades were very tough, cut well, I believe that if you want to put the time in you could take L-6 a long way.
 
I haven't used Admirals, I have used Cruciable's and it responded well to low temp forging and thermal cycling, and mulitple anealing cycles. I had the best blades from nomilizing once at critcle, then three more time just below criticle where the magnet was starting to loose magnetivity. Then anealing in a wrap of kwool with two slabs of red hot steel.
 
Thanks Ed and Will52100. Do you know if the stuff you were using was the variety with or without Molybdenum?

bladsmth, you need to reread my above posts. I know how to heat treat both kinds of L-6. I already have both Crucibles and Timkens data sheets. What I'm trying to determine is WHAT Admiral Steel sells (which I have not been able to find out despite literally hours of using search engines), so that I can then know what heat treating procedures to use.
 
I have been working with the L6 offered by Crucible service centers for longer than I care to rememeber now and have evolved through a few ways o get the most out of it. My experience has shown that Admirals chemistry is probably not he same as the stuff from Crucible. One of th efirst thitngs I did when I got my hands on the Admiral stuff (after hearing of folks doing htins like sawing it or drilling it after forging) was to heat it to 1550F and let it just cool in the still air and then take a Rockwell reading... high 30's. I then quenched it and got a beautiful 63HRC. The other L6 I have worked with would reach a 61HRC just cooling in air and nobody would be drilling or cutting it until after a very involved anneal.

Folks have heard me explain these differneces and extrapolated that I was badmouthing the Admiral stuff, I need to clear this up the best I can. It is GOOD stuff, it jsut behaves differntly and this is a good thing. It welds like a dream and makes wonderful damascus, and is suited to be mixed with a much wider range of steels than my Crucible stuff, although the latter is still my favorite.

I have found that if one can duplicate the conditions that the industrial specs use, that L6 will respond very well to the recommendations on those same spec sheets. If you can, soak the snot out of it! It will harden quite deeply and be nearly indestructable.

Now as for the Admiral stuff, since I have yet to see a chemistry that exactly matches its behavior I am going to take some guesses here, but don't worry I will try to make those guesses as educated as possible, and I have successfully treated the stuff. I would say that you could heat treat it similar to 5160 or 4340 and heat it to around 1525F (my safe estimation) and soak for as long as you can perhaps not exceeding 15 minutes. If that soak is too long for ones facilitites then I would go to 1550F for a shorter time.

Quench into a good medium speed oil. And then begin your tempering at 400F to stabilize things, but you may need to go as high as 440F to get in the range of 58HRC, if your soak time was longer. If you just got it to temp and then immediately quenched, 400F may be enough. There are a whole spectrum of but's, if's and other exceptions due to all the factors that could change things, but that is my ball park recommendation overall.

edited to add: BTW you will know if there is moly there if you have to use the higher tempering temps in order to get the desired HRC. I don't think it is there in this stuff, or if it is it is not as much as the typical batch from Crucible.

*edited to change 68HRC to 58HRC as Raymond so rightly pointed out
 
Thank you Kevin! This is exactly the info I'm after. I'm kind of busy today so I'll respond to this in more depth later.
 
I believe I read in a simular post on the Admiral L-6 that the specks were real simular to Crucible's. When I would run hardening temps with Admiral in my oven it was the strangest thing. The blades would come out with so much decarb they reminded me of candy bar wrappers. I ran simular tempering temps that Kevin suggested. I think the 68hrc was ment to be 58hrc.
 
"I have found that if one can duplicate the conditions that the industrial specs use, that L6 will respond very well to the recommendations on those same spec sheets. If you can, soak the snot out of it! It will harden quite deeply and be nearly indestructable. "


Are you referring to the Admiral stuff or Crucible's? I've noticed that the Admiral L6 will make a very visible transition zone if edge quenched. That makes me wonder if it's deep hardening.


"Now as for the Admiral stuff, since I have yet to see a chemistry that exactly matches its behavior I am going to take some guesses here, but don't worry I will try to make those guesses as educated as possible, and I have successfully treated the stuff. I would say that you could heat treat it similar to 5160 or 4340 and heat it to around 1525F (my safe estimation) and soak for as long as you can perhaps not exceeding 15 minutes. If that soak is too long for ones facilitites then I would go to 1550F for a shorter time."


Sounds like a good place to start. I have an Evenheat oven so soaking is not a problem.

"Quench into a good medium speed oil. And then begin your tempering at 400F to stabilize things, but you may need to go as high as 440F to get in the range of 58HRC, if your soak time was longer. If you just got it to temp and then immediately quenched, 400F may be enough. There are a whole spectrum of but's, if's and other exceptions due to all the factors that could change things, but that is my ball park recommendation overall."


The only "engineered" quenching oil I have is Shell H201, which is almost identical to Texaco type A. Do you think this is too slow?


"edited to add: BTW you will know if there is moly there if you have to use the higher tempering temps in order to get the desired HRC. I don't think it is there in this stuff, or if it is it is not as much as the typical batch from Crucible."


I have no way right now to check the hardness, other than files and the brass rod test, for what those are worth. A Rockwell tester is at the top of my wish list right now.
Judging from how soft the Admiral L6 is after normalizing, I'd say it doesn't have moly. Just a guess though. It sure acts different than champalloy.


"*edited to change 68HRC to 58HRC as Raymond so rightly pointed out"


I knew what you meant. :D
Thanks again for the help.
 
Phillip Patton said:
Are you referring to the Admiral stuff or Crucible's? I've noticed that the Admiral L6 will make a very visible transition zone if edge quenched. That makes me wonder if it's deep hardening.
Click to expand...
I was referring to L6 in general. 5160 will also form a very distinct line when edge quenched and it is considered an oil hardening steel.

The only "engineered" quenching oil I have is Shell H201, which is almost identical to Texaco type A. Do you think this is too slow?
Click to expand...

It should work, but not knowing the exact chemistry I can give no guarantees. This is just speculation but a wild guess on my part would suggest that a possible chemistry could be similar to .70%C, .80%Mn, 1.75% Ni, .75%Cr.

The stuff quenched fine in Parks AAA

I have no way right now to check the hardness, other than files and the brass rod test, for what those are worth. A Rockwell tester is at the top of my wish list right now.
Judging from how soft the Admiral L6 is after normalizing, I'd say it doesn't have moly. Just a guess though. It sure acts different than champalloy.
Click to expand...

The file is your best bet for now. That brass rod stuff is highly touted without mentioning the fact that it is influenced by edge geometry more significantly than heat treat. The extended soaks are most important if you are hardening from a spheroidized condition. You can cut down on the soak requirements by going with fine pearlite, i.e. normalize your blade instead of a long spheroidal type anneal. Since this stuff will stay in the 30's RHC after air cooling this should work fine.

I say to each his own on a lot of steel treatments if it is a steel that doesn’t interest me. Folks can get as "creative" as they like in their heat treating and I will let it be as it is nothing to me. But I know L6, I know it intimately from many years of working it and examining it and if you have the equipment and follow the recommendations of the folks who made the stuff, the steel will work well.
 
You must log in or register to reply here.
Back
Top