52100 heat treat summary.

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Utican

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Sep 18, 2010
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I have made a few blades from 1084 and 1080 so far with good results. I am copletely satisfied with preformance of 1080/1084 in puukko and leuku style blades I made. I also made a few kiridashis and small carving type blades. I am about to place an order for new shippment of 1084 from Aldo and was contemplating getting a bar of 52100 to try out. The research has lead me to beleive that 52100 would offer improved wear resistance and also finer grain structure. I would use 52100 for the carving blades and kiridashis. Off course proper heat treatment would be necessary to make it work. This is my first attempt at using alloy steel. I do have an electric kiln so temperature control is not an issue. Vegitable oil is quenching medium. All stock removal. Steel sourced from Aldo. I did the research and this is what I came up with. It is copied from another thread.

1625 soak air cool
1575 soak and air cool
1530 soak and air cool
1510 soak 20 min quench in Parks 50

The questions are,
1. would I get good results using vegitable oil as quenching medium.
2. I have read on Cashen's site that he recommends a lower Austenizing temp of 1475 for final quench and reaches 67 hcr.

I appreciate your input.
 
As you said, the 1475F austenizing temp would be better from what we hear from Kevin Cashen's research. That apparently solves the RA problem and other undesirable things that can happen with hypereutectoid steels. My understanding is that the thermal cycles that yo motion are desribale because Aldo's 52100 comes in a spheroidized state to make it easier to work, so you need to dissolve this nice little carbides. As for the oil, with a deep harding steel, I am not sure how much difference it will make compared to say Parks AAA, but I will say this. Unless I am wrong, Mr. Cashen austenized his 52100 with big temp salts, BUT he used AAA for quenching instead of the normal low temp salts that he typically uses on his deep hardening steels like O1 and L6 and if he chose to do that, there is a very good reason.
 
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I've been using Aldo's 52100 for a couple years now.

1650 10 min air cool to magnetic.
1550 10 min air cool to magnetic.
1450 10 min air cool to magnetic.

austentize at 1475 for 10min, quench in medium oil.

Temper at 400f for 2hX2. Check hardness and adjust temper as needed.

enjoy one of the highest performing steels you will ever use. :thumbup:
 
Willie71 said:
I've been using Aldo's 52100 for a couple years now.

1650 10 min air cool to magnetic.
1550 10 min air cool to magnetic.
1450 10 min air cool to magnetic.

austentize at 1475 for 10min, quench in medium oil.

Temper at 400f for 2hX2. Check hardness and adjust temper as needed.

enjoy one of the highest performing steels you will ever use. :thumbup:
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+1 for me- using same steps- probably got it from your posts Willie : ) Only on my 4th 52100 blade though... Just made a Deba out of 1/4". I have been tempering 350f for kitchen knives though and so far very happy with the performance. This steel takes a very sharp edge with water stones!
 
+1 on the instructions given. 52100 usually comes heavily spheroidized and NEEDS the higher normalizing heat of 1650F. But this may cause some "grain growth", so we thermal cycle using reducing temps to "refine" the grain size. And it is more carbide refinement than anything, from what I understand. Not necessarily the ferrite grains themselves.

Does not need fast oil. 130F canola works pretty darn well.

My routine:

1650F 5 minutes air cool
1550F 5 minutes air cool
1450F 5 minutes air cool
1475F 10-15 minutes soak into 130F canola
No way of RC testing, but a brand new fine cut file will not even begin to dig in to or scratch the hard steel. Guessing well north of 64, prob 66-67.
If not protected, all that thermal cycling will cause some decarb that needs to be ground off. (and can trick you into thinking it didn't harden properly)

If I want to do normalizing first and grind later to minimize decarb:
1650F 5 minutes air cool
1550F 5 minutes air cool
1450F 5 minutes quench
1250F for two hours
grind/drill/sand/etc
1475F for 15 minutes soak into 130F canola

Works REALLY well. And a HUGE thank you again to Kevin for the help in understanding how to handle that steel.
 
I agree with everyone else, thanks to Kevin Cashen for his work with this steel. The process is simple, repeatable, and reliable.

And to clarify, 350 temper is a good starting point for a kitchen knife. :thumbup:

Stuart, I get Rc66 out of quench consistently.
 
How many of you use a subzero quench with 52100, and have you tested to see what it adds?
I've been doing that, but the few knives that I haven't treated have also been fairly spectacularly good in terms of fine edge stability.
 
elementfe said:
How many of you use a subzero quench with 52100, and have you tested to see what it adds?
I've been doing that, but the few knives that I haven't treated have also been fairly spectacularly good in terms of fine edge stability.
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The process described above results in minimal retained austentite, so subzero isn't needed, as in the last step, you are only getting about 0.85% carbon into solution, with the rest going to carbide formation. If you austentize at 1500f or higher, you will end up with retained austentite, as you get more than 0.85% carbon into solution, which is why industry uses subzero. In bearings, larger carbides are desirable and are formed with higher austentizing temps, as they add wear resistance. They aren't a good thing when a fine edge is preferred.
 
elementfe said:
How many of you use a subzero quench with 52100, and have you tested to see what it adds?
I've been doing that, but the few knives that I haven't treated have also been fairly spectacularly good in terms of fine edge stability.
Click to expand...

Last week I hardened the 1/4" Deba and since I was doing three other stainless AEB-L blades I had the dry ice and alchohol already prepped. I had read that it can add a point or so of hardness on 52100 so I went ahead and used it on the Deba as well. I don't have equipment accurate enough to be absolutely certain of the difference, but it did seem to add a point to my measurements and the blade felt a bit harder to work after treating than normal so I "think" it made a difference.
 
Just a little comment here. I have the sneaking suspicion that Mr. Cashen might have been trying in part to "debunk" some of the stuff out there about 52100 and in the process, discovered something perhaps unexpected and good about the steel. He told me a while back that there are steels where you "take what the chemistry gives you" (I seem to recall he was talking about A2 at the time) and some where you can fine tune the process and perhaps find some extra performance in blade applications by varyign a little from the :industry standard" heat treat. Remember that for 52100, the industry standard HT is designed to give you lots of nice abrasion resistant carbides for bearings. What he did was just drop the austenizing temp maybe 50 degrees and voila!!!! Look what My understanding is that the alternate HT that guys like Bob Dozier came up with for D2 had the same beneficial effect when came to use in blades. We don't want a giant pile of big honkin' carbides, but we do like having perhaps a slightly smaller mound of very fine, abrasion restraint carbides properly distributed in the mix. ;)
 
jdm61 said:
Just a little comment here. I have the sneaking suspicion that Mr. Cashen might have been trying in part to "debunk" some of the stuff out there about 52100 and in the process, discovered something perhaps unexpected and good about the steel. He told me a while back that there are steels where you "take what the chemistry gives you" (I seem to recall he was talking about A2 at the time) and some where you can fine tune the process and perhaps find some extra performance in blade applications by varyign a little from the :industry standard" heat treat. Remember that for 52100, the industry standard HT is designed to give you lots of nice abrasion resistant carbides for bearings. What he did was just drop the austenizing temp maybe 50 degrees and voila!!!! Look what My understanding is that the alternate HT that guys like Bob Dozier came up with for D2 had the same beneficial effect when came to use in blades. We don't want a giant pile of big honkin' carbides, but we do like having perhaps a slightly smaller mound of very fine, abrasion restraint carbides properly distributed in the mix. ;)
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Very well said! And what Warren said about dropping aust temp dropping RA....very well said.
 
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Willie71 said:
The process described above results in minimal retained austentite, so subzero isn't needed, as in the last step, you are only getting about 0.85% carbon into solution, with the rest going to carbide formation. If you austentize at 1500f or higher, you will end up with retained austentite, as you get more than 0.85% carbon into solution, which is why industry uses subzero. In bearings, larger carbides are desirable and are formed with higher austentizing temps, as they add wear resistance. They aren't a good thing when a fine edge is preferred.
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Thanks!!
I keep rereading Mr. Cashen and Bladsmith's writeups on the fundamentals of HT, and that info is there, but I hadn't really grasped that part of it- thanks for the compact explanation!
 
Thank you all for your input. I cant wait to get my grubby hands on some 52100. Local shop will measure hardness for me. It will be interesting to see how smoothly it goes (or not) and what the results are. I will update with results. 52100 sounds like something that would be suitable for a straight razor. I have been straigt razor shaving for a couple of year now and it would be awsome to do it with a blade I made. I was going to order steel yesterday but Aldo is out of 1084 as of now, eta mid March.
 
samuraistuart said:
52100 can make a great straight razor indeed
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Yeah it makes a great razor. Or kitchen knife. Our camp knife. Or pocket knife. Or edc knife, which is what my personal Dart EDC is made from. It's a great great steel that gets hard and stays sharp with a fine edge. I love it. 52100 is my go to carbon steel and about the only thing I use anymore.
 
I am so excited. I just made up experimental batch consisting of three small blades and just started heat treating them. I will have the results of hardness tomorrow.
 
The result are in and I goofed up somwheres along the line. I left one blade untempered and the hardness test results were dissapointing 60 hrc over all. I went over the procedure and realized that in my excitement I did not bring oil up to temperature. Re doing the test batch as we speak. Ill keep you guys updated.

To re cap I brought it up to 1650f and held for 10 min then air cool. followed by 1550f and held for 10 min then air cool and 1450f and held for 10 min then air cool.

Finally I heated to 1475f soaked for 20 min and quenched in oil. This time it will be 130 f
 
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Re did the heat treat yesterday with quenching oil at proper temperature. After one hour temper at 375 or so the blades came back at 61 hcr. Im happy. It is noticabelly harder to hone at this hardness as opposed to 1084 at 58-59 hcr. Who would have thought two points mean this much.

I want to thank everyone involved once again.( I feel like giving one of those cheesy speeches that athletes give after a win). I also want to thank Kevin Cashen for translating all that metalurgical mumbo jumbo in to english and making clear and concise heat treat and grain refining instructions.

It is also interesting to note that I would swear that the color of the 52100 appeares more silver compared to aldos 1084

Now I am going to stick with 1084 and 52100 for a while. I think with these two steels possibilities are endless.
 
Utican about the color of 52100 I see the exact same thing compared to straight spring steel. It is more silver or shiny I think due to the 1,5% Cr in there. Polishes up much nicer than spring steels to me anyway. Glad you are making headway with your heat treat. Don't be shy about modifying some of it and branching out.
 
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