52100...what am I missing?

kvehikite

kvehikite

Joined
Jan 8, 2015
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I'm working with some 52100. First time, so I'm learning. I can not get it to harden.
Here's my process (pulled from another thread on the BF):

1650 for 5 min soak. Cool to black
1550 5 min soak. Cool to black
1450 5 min. Soak. Cool to black
1475 15 min soak quench in 120 degree canola oil...

Soft as butter. What am I missing. I did this twice today.
Any thoughts. Thanks
 
Your temp is to high and your soak to Long. you didnt say If the blade was forged or not. If your forging the blade do three normalizing cycles bringing the blade up to temp and allowing it to.cool to room temp without a quench. Then take the blade up to 1250 and let it normalize for about 5-10 minutes. Them ramp the temp up to 1525 with 5-10 minute soak and immediately quench in a fast quench oil warmed to 130 Degrees. Temper at 400 for 2 two hour quench cycles. If your not forging just skip the 3 normalizing steps.
 
Apply to 52100 bar from Aldo:

20-30 minutes at 1650F because 5 is not long enough to release carbon from spheroidized annealed form.

kvehikite said:
I'm working with some 52100. First time, so I'm learning. I can not get it to harden.
Here's my process (pulled from another thread on the BF):

1650 for 5 min soak. Cool to black
1550 5 min soak. Cool to black
1450 5 min. Soak. Cool to black
1475 15 min soak quench in 120 degree canola oil...

Soft as butter. What am I missing. I did this twice today.
Any thoughts. Thanks
Click to expand...
 
J. Hoover said:
Your temp is to high and your soak to Long. you didnt say If the blade was forged or not. If your forging the blade do three normalizing cycles bringing the blade up to temp and allowing it to.cool to room temp without a quench. Then take the blade up to 1250 and let it normalize for about 5-10 minutes. Them ramp the temp up to 1525 with 5-10 minute soak and immediately quench in a fast quench oil warmed to 130 Degrees. Temper at 400 for 2 two hour quench cycles. If your not forging just skip the 3 normalizing steps.
Click to expand...

bluntcut said:
Apply to 52100 bar from Aldo:

20-30 minutes at 1650F because 5 is not long enough to release carbon from spheroidized annealed form.
Click to expand...

Thanks for the response. But now I am corn-fused. I guess I will try both metods and see what happens.
I understand J hoovers process, it's straight forward.
Blunt cut> after the 30 min soak at 1650 do you proceed with the 1550, 1450 etc?
 
Yes, grain refinement then harden...
kvehikite said:
Thanks for the response. But now I am corn-fused. I guess I will try both metods and see what happens.
I understand J hoovers process, it's straight forward.
Blunt cut> after the 30 min soak at 1650 do you proceed with the 1550, 1450 etc?
Click to expand...

edit: you might want to clay or ssfoil while normalizing for 20+ minutes, otherwise decarb will be deep.
 
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1525-50 will get you a nice ball bearing. Current wisdom says that 1475 will get you a better blade.
 
I did an experiment a couple years back with an extended subcritical anneal and directly to austentizing. Didn't work. Aldo's 52100 needs the 1650 normalize to break up the carbides. The subcritical anneal and 1525 austentize will work in industrial applications with other sources of 52100, but for knives the thermal cycling methods is best. Small evenly placed carbides and minimal retained austentite are the result. Perfect for knives,
 
"Soft as butter" is one thing, not getting the most from your steel is another.
In order to be that soft, something dramatic is wrong- I hate to even suggest it, but (don't ask me how I know) it is possible to get steels mixed up while working, stuff like that, and use a steel that simply won't harden under those conditions, that you were sure was something else.

If that was actually 52100, I don't see how it could possibly be dead soft after that last heat/quench.
Am I wrong about this?
 
Did you grind away any decarb?
If so, and it's still soft-I agree with the last. If it's soft as butter it's not actually 52100-I've had distally forged tangs come out too hard to drill from air cooling.
I have taken a piece of Aldo's 52100, forged it to shape and differential torch hardened it and gotten full hardness, with no other cycles (although normally I do thermal cycle a couple times after forging).
 
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elementfe said:
"Soft as butter" is one thing, not getting the most from your steel is another.
In order to be that soft, something dramatic is wrong- I hate to even suggest it, but (don't ask me how I know) it is possible to get steels mixed up while working, stuff like that, and use a steel that simply won't harden under those conditions, that you were sure was something else.

If that was actually 52100, I don't see how it could possibly be dead soft after that last heat/quench.
Am I wrong about this?
Click to expand...

J W Bensinger said:
Did you grind away any decarb?
If so, and it's still soft-I agree with the last. If it's soft as butter it's not actually 52100-I've had distally forged tangs come out too hard to drill from air cooling.
I have taken a piece of Aldo's 52100, forged it to shape and differential torch hardened it and gotten full hardness, with no other cycles (although normally I do thermal cycle a couple times after forging).
Click to expand...

I did grind away decarb thinking that was it, with no change. The thought had occurred to me that I had mixed steels, but I marked it as soon as I recieved it. I will see what happens tomorrow.
 
J W Bensinger said:
Did you grind away any decarb?
If so, and it's still soft-I agree with the last. If it's soft as butter it's not actually 52100-I've had distally forged tangs come out too hard to drill from air cooling.
I have taken a piece of Aldo's 52100, forged it to shape and differential torch hardened it and gotten full hardness, with no other cycles (although normally I do thermal cycle a couple times after forging).
Click to expand...

^^ This.
We're all trying to get the very most out of our blades, but I've taken 52100 and treated it basically like 1084 (heat to cherry and quench without soak, temper with a propane torch) and gotten very serviceable knives.
Something is going on, and it'll probably turn out to be something simple.
 
One more vote for mixed up steel, 52100 in my experience will air harden quite a bit in blade thicknesses. I've always had to do subcritical cycles after forging just to be able to drill it reliably.
 
kvehikite said:
I did grind away decarb thinking that was it, with no change. The thought had occurred to me that I had mixed steels, but I marked it as soon as I recieved it. I will see what happens tomorrow.
Click to expand...

Are you sure the kiln is reading correctly?

If you want, send me a coupon and I'll use my recipe for 52100 that I have consistent results with to see what happens. Pm me and I'll give you my address.
 
Willie71 said:
Here's a link to the experiment I did.

http://www.bladeforums.com/forums/s...2100-(Aldo-s)-alternate-heat-treat-Epic-Fail-!!!!!!

You have to read past the first few posts to get to the meat of the discussion. I discussed this steel with Kevin Cashen at a hammer in in 2014 as well, and your process in the OP should work with 10 minute soak times. You should get consistent Rc66 out of quench.
Click to expand...

Digging through this thread http://www.bladeforums.com/forums/sh...eat-Epic-Fail-!!!!!! I found a post by Nick Wheeler which really got me thinking. Here's his quote:

"One thing that jumps out at me from a lot of these posts, is the time spent in kilns. Unless you're coating the blade with something prior to all the trips in the kiln, you're going to have to do some grinding to get back to good steel.

With my Paragon, if I run a blade through all the thermal cycles and do a long soak at austenitizing temp, a file will bite into the surface of the as-quenched blade.

I had this happen with CruForgeV. It was low 50's on the ricasso and a file bit right in. I surface ground 0.010 off and re-tested the Rc and found it was 65/66.

Just something to think about."

As I am not accustomed to the level of thermo cycling required for 52100 I may be underestimating the amount of decarb that is on the blade. Any thoughts?
 
According to guys who have worked with it a lot. Cru Forge V requires an even higher temp "thermal cycle' to break up all of those little sphereoidized carbides, like 1750F. That probably wasn't a big issue until people made stock removal blades for it. I have only forged the stuff and it ends up highly abrasion resistant and takes a screaming shape edge when forged, cycled and heat treated using the old 1500/400 formula. The the next time they I use some, I plan to play around with it a bit.
 
kvehikite said:
Digging through this thread http://www.bladeforums.com/forums/sh...eat-Epic-Fail-!!!!!! I found a post by Nick Wheeler which really got me thinking. Here's his quote:

"One thing that jumps out at me from a lot of these posts, is the time spent in kilns. Unless you're coating the blade with something prior to all the trips in the kiln, you're going to have to do some grinding to get back to good steel.

With my Paragon, if I run a blade through all the thermal cycles and do a long soak at austenitizing temp, a file will bite into the surface of the as-quenched blade.

I had this happen with CruForgeV. It was low 50's on the ricasso and a file bit right in. I surface ground 0.010 off and re-tested the Rc and found it was 65/66.

Just something to think about."

As I am not accustomed to the level of thermo cycling required for 52100 I may be underestimating the amount of decarb that is on the blade. Any thoughts?
Click to expand...

Decarb would be my guess. Can you bend the blade and have it take a set? If it's soft, it will take a set pretty easily. If it's hard, it won't.
 
I'm thinking either a heavy layer of decarb, or a mix up with steel. One easy test is to take a scrap piece and heat with a torch till a magnet won't stick and quench in warm oil or water. Clamp it in a vise and smack it with a hammer. If it breaks clean with a fine grain showing it's at least hardenable and probably 52100 like you thought.

My normal recipe for 52100 is after forging to normalize a couple times in the forge, once at about 1550, then about 1200. After rough grinding I take it to 1625 in the oven and quench in a slow oil, then heat to 1350 and quench, then to 1250 and slow cool in the oven. I don't soak the blade at temp more than a minute or two. After that I heat the blade, either in the oven or the lower third with a torch for a differential quench, to 1500-1525 and quench in a slow oil heated to 135 deg. After that I let it sit for 24 hours and do it twice more. I know a lot of people don't agree with the triple quench, but it works for me and after a lot of testing I'm sticking with it. Any way, at no time am I letting the blade soak for long periods of time, but even then I have to clean a little decarb off, but the blade will skate a file after quench. After the 3 quenches I temper for 2 hours, 3 times, at 375 deg.
 
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