Thoughts and opinions regarding A2

ACLakey

ACLakey

Joined
Jan 24, 2016
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Okay, let me preface this by saying I have only made a few knives with A2 but wanted to share my thoughts.

As we know, A2 has a reputation of being a tough steel, relatively easy to sharpen and holds a descent edge. It benefits from a cryo treatment and with cryo performs well around 60 rc. With that out of the way, I was thinking about using A2 for a series of knives with blades in the 3-4.5" range used primarily for hunting and skinning tasks....cutting tasks not hard use tasks. I was planning on using .125" stock, taking the bevel to a thinner .010" prior to sharpening and using a high flat grind or hollow grind to make for a good slicer. My thought is with the toughness characteristics of A2 I could make a thin slicer that would hold up to field use cutting flesh and other hunting tasks. Do you feel this would be a decent plan of attack? Would you recommend another steel and if so which one?
 
A2 will perform just fine for that. I'm coming to prefer Z-Wear for that kind of task, as it's tougher and has better wear resistance, but with the resulting downside of being more work to sharpen.

But A2 will work very well.
 
It does more then just benefit from cryo. I LOVE A2 and I just heat treated a customers blade that came out of the cryo and tested at 67rc. It can achieve a very fine edge and is a very common steel so pricing is not bad.
 
Nice! I am really torn between using A2 or D2 for these knives. With those numbers you posted, how well would an A2 blade with a 61 or higher RC perform compared to a similar blade in D2. It is a steel that I need more time with for sure.
 
The old Effigham, IL Black Jack knives were A2. Still some of the sharpest out-of-the-box knives I've seen. The Trail Guide model is a small hunter for tasks like you mentioned, very very sharp. My personal hog knife I made from A2. I'll know how it works in a few weeks. I'm a fan.

JT, can you give us a snap shot of your A2 times and temps? Do you use the slow ramp (not exceeding 400˚ per hour) or as fast as possible?
 
66RC is common with my heat treat formula and a 400° will drop it 63RC and a 450° temper brings it to 61rc. I have been wanting to play with it in the 63RC range. But I don't think 61rc is at all out of the question even 62 should be ok depending on the use and the edge geometry.
 
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ACLakey said:
Okay, let me preface this by saying I have only made a few knives with A2 but wanted to share my thoughts.

As we know, A2 has a reputation of being a tough steel, relatively easy to sharpen and holds a descent edge. It benefits from a cryo treatment and with cryo performs well around 60 rc. With that out of the way, I was thinking about using A2 for a series of knives with blades in the 3-4.5" range used primarily for hunting and skinning tasks....cutting tasks not hard use tasks. I was planning on using .125" stock, taking the bevel to a thinner .010" prior to sharpening and using a high flat grind or hollow grind to make for a good slicer. My thought is with the toughness characteristics of A2 I could make a thin slicer that would hold up to field use cutting flesh and other hunting tasks. Do you feel this would be a decent plan of attack? Would you recommend another steel and if so which one?
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My hunting knife is exactly this in A2.
It has only dressed, skinned, and butchered one deer, but all the edge needed was cleaning, not sharpening.
I'm a huge fan of A2, for a steel that can be heat-treated with within-reach equipment. My current two picks for carbon steels are 1084 and A2. It seems to like 30d inclusive, but no narrower. My target is usually 60Rc.
 
I think because A2 is such an old Aloy that it is written off as a contender to the modern super steels. My wife is rather picky with her kitchen knives and the 2 knives I have made her out of A2 are her favort blades. The short pairing knife gets a corse grit sharpening and then a leather strop and it cuts through chicken like it's not there, she calls it her chicken light sabre. I also love D2 quite a bit for a lot of stuff but A2 takes a finer edge. D2 can be treated to have a fine grain as well but I feal D2 works best with a corse finished edge and excels on meat.
 
JTknives said:
66RC is common with my heat treat formula and a 400° will drop it 63RC and a 450° temper brings it to 61rc. I have been wanting to play with it in the 63RC range. But I don't think 61rc is at all out of the question even 62 should be ok depending on the use and the edge geometry.
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JT, If that was a reply to my question I apologize. I should have been more clear. I meant in the austenitizing, do you ramp up as fast as possible or do you ramp up slowly? The manufacturer's notes that I've read along with articles by Roman Landes and Joe Szilaski recommend not exceeding 400˚ per hour when ramping up to austenitizing temp. But I have read other formulas that go AFAP with good results. Curious which method you use.
 
Oh ok.
I heat my oven to 1775° and hold that temp for at least a half hr to one hr to make sure the oven is all nice and even inside. I use 2 stainless pipes in my oven as blade holders and it also helps even out the temp as it's extra mass and the edge of the pip is close to the tip of the TC. Once the oven has soaked I put the blade into the oven between the pipes and close the door. I watch the temp on the controller and once it comes back up to 1775° I start the 45min timer. I find that if after you open and close the oven door if it takes a long long time for the temp to come back up then your oven was not soaked long enough. It should only take a min or so to come back up to temp. I quench between quench plate on my anvil using a quick clamp. I pull the blade out and it goes between the plates and I gently clamp down on it. This keeps everything straight unless it's AEB-L that stuff just seams to have a mind of its own. After its cold I remove the blade from the foil and go right into the cryo. Befor cryo it will RC test at around 62-63rc, this is not that accurate as I find that air hardening steels need time to reach there peak hardness. I leave the blade in cryo for 1hr, this is the amount of time it takes me to process another blade so once the next blade is done it goes in the cryo and the last one comes out. I have playied with cryo times to see what difference it makes and anything over 1hr does not seams to make a difference. I have soaked for 24hrs and it comes out the same hardness as 1hr blades. So take it out of the cryo and let them gently warm up to ambient room temp. I measure 66RC and like I said I had one come out at 67 after cryo. I then sort out where the bow is as even a straight blade will have a very slight bow. I then clamp them to a thick steel plate and put this in the preheat tempering oven.

remember not all heat treat ovens are the same, 1775° works great for me but your oven could be different then mine and be higher or lower actual temp then what mine is when it's set to 1775°.
 
JT, I ordered a bunch of A2 so I'll be hitting you up for some heat treatment in a few weeks.
 
I really like A2 it is a very good choice. Cryo gets even more out of it.

If it is all I had to make knives with, that would be fine.
 
ACLakey said:
JT, I ordered a bunch of A2 so I'll be hitting you up for some heat treatment in a few weeks.
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Sounds like a plan. We are closing on the house soon but Not moving right away becaus the new place does not have a shop yet. Once we get the shop put up or the snow melts we are moving, if no shop by then then we will just keep using this shop. I'm doing some A2 and 3v right now as we speak.
 
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I've made numerous skinners, hunters and camp knives from A2 for professional guides that use them harder in a few weeks then most guys will in a lifetime. I run it at 62RC with cryo. Cutting machines. you won't go wrong with A2.
 
i4Marc said:
Does A2 need cryo or will subzero with acetone and dry ice suffice?
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The -100°F cold treatment will reduce RA in A2 to ~9%. The -300°F LN2 cryo treatment will reduce RA in A2 to <2%. Both samples oil quenched from 1775°F. (from "Heat Treating, Including Steel Heat Treating in the New Millennium, An International Symposium in Honor of Professor George Krauss" (ASM Heat Treating Society) 2000.)

Air/plate cooling may (may not) have slightly higher RA%?? I've heard that oil quenching air hardening steels results in slightly lower RA.
 
Good plate quenching on flat stock is faster than oil quenching. Faster quenching=less RA.

Hoss
 
Hoss, is it faster assuming that you are using foil? I ask because AA and its analogues are 11-13 second oils and I hear people say that they used compressed air to "speed up" quenching with plates. Is the "speed" an issue of air hardening steels having austenizing temps 250-600 degrees higher than carbon steels?
DevinT said:
Good plate quenching on flat stock is faster than oil quenching. Faster quenching=less RA.

Hoss
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