How to Heat Treat 52100

just had my new 52100 batch HT check hardness tested and i was bummed cause i thought it was lower then it should have been but since i had not cryoed the test piece i now know what happened. also been maybe 2 years since i have done any 52100. got used to seeing as tempered 62-63 from working XHP so much. looks like im going to soak a bit longer and make sure to get my LN filled
 
Great stuff, thanks Larrin. As soon as I have some time I'm going to be testing for differences between fast oil (P50) and slightly slower oil (McMaster Carr 11 sec.). It seems like the folks that are getting the highest as quenched hardness all seem to be using the 11 second oil or similar.
 
Thanks a deeper look into ht 52100 :thumbsup:. I think, a wide gap of toughness between 52100 vs 1095&O1 worth further investigation. Excerpt from your article - clearly showed your uncomfortable and contradictory reasoning about toughness among these steels.

It is not entirely clear why 52100 would be tougher than O1 and 1095, since those steels also have a small volume of carbide for high toughness. I believe that the lower carbon in solution with 52100 from the chromium addition gives it better toughness. Alternatively, it may be that the larger amount of carbide in 52100 and CruForgeV provides better resistance to grain coarsening.​
 
E.Carlson said:
Great stuff, thanks Larrin. As soon as I have some time I'm going to be testing for differences between fast oil (P50) and slightly slower oil (McMaster Carr 11 sec.). It seems like the folks that are getting the highest as quenched hardness all seem to be using the 11 second oil or similar.
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Larrin and I have a few more samples to test using medium oil. We will run control samples with AKS and NJSB 52100, as the compositions are a little different.
 
My thoughts on the annealing procedure for stock removal guys....The divorced eutectoid transformation (DET) is usually done at the mill. Or maybe better stated, "should" be done at the mill. From Verhoeven's "Metallurgy of Steel" concerning the DET anneal, "It requires no quenching and is therefore used in industry to produce the spheroidized structures of cementite + ferrite in which these steels are supplied from the steel mill." For stock removal guys, there should be no need to perform this procedure. And to that point, there should be no need to normalize or cycle it, either. On the other hand, if 52100 is being forged, and especially if the blade needs machining/grinding/drilling, then the idea is that the DET is the best anneal for hypereutectoid steels.

But there is another consideration...with the spheroidized issues we have seen come from certain mills, and in order to know exactly what condition your blade is in prior to austenitizing, it makes perfect sense to set up the matrix the best way possible. Normalize, cycle, anneal, austenitize/quench/temper.

Good thoughts, as usual, Larrin. Makes me think harder and harder about squeezing the most out of what steels have to offer, and how to go about doing it.
 
Good stuff as always.

I saw your micrographs on IG - would your current setup be sufficient to verify grain refinement if 52100 vs 1095? Do you think that would be worthwhile?
 
Nick Dunham said:
Good stuff as always.

I saw your micrographs on IG - would your current setup be sufficient to verify grain refinement if 52100 vs 1095? Do you think that would be worthwhile?
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Revealing prior austenite grain boundaries is incredibly difficult, and even more so the finer the grains are. So I think measuring toughness is the more practical solution. Because if the toughness isn’t improved the grain refinement isn’t worthwhile anyway.
 
good read, and really interesting to see how little gain there is(and actual loss in toughness) when giving 52100 cryo. Always assumed that it was across the board improvements doin so. Partly why i had never worked with the steel to date. Think im going to order up a few bars now and play around with it.
 
Aidenag said:
good read, and really interesting to see how little gain there is(and actual loss in toughness) when giving 52100 cryo. Always assumed that it was across the board improvements doin so. Partly why i had never worked with the steel to date. Think im going to order up a few bars now and play around with it.
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Yes cryo usually reduces toughness, in the best case scenario it will lead to similar toughness.
 
DeadboxHero said:
I used Larrin's article protocol for the knife in this video with NJSB 52100.
Very stable with even with the 1525f and low temper.

I like it.

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This is a really good steel. It was my go to monosteel when a hamon wasn’t wanted until I figured out the z-wear heat treat. I find it his a more stable edge than O1 or 1095, and about the same as W2.
 
Forgive the simpleton question, but are any of these findings more than theoretical? Obviously you actually tested these, so they are real findings. What I’m driving at is over a range of 100 degrees difference in austenizing temp there appears to only be a couple points of hardness and 5 ft/lbs of toughness difference. Short of scientifically testing the comparison pieces, is there any real world scenario in which these small differences would actually be observable in use (especially considering the “low” numbers still appear to be pretty good numbers)?

It’s also interesting to me that there is common advice that if you don’t have precise heat treating equipment using a steel like 52100 would be no better and actually worse than using something else. However, the data here seems to show wandering off from “ideal” intentionally to test the range still resulted in better numbers than some of the ideals for other steels in the comparison chart. Would the concern be more with hold times than temp ranges (as there appeared to be some difference between the 10 and 15 minute samples potentially).
 
lanternnate said:
Forgive the simpleton question, but are any of these findings more than theoretical? Obviously you actually tested these, so they are real findings. What I’m driving at is over a range of 100 degrees difference in austenizing temp there appears to only be a couple points of hardness and 5 ft/lbs of toughness difference. Short of scientifically testing the comparison pieces, is there any real world scenario in which these small differences would actually be observable in use (especially considering the “low” numbers still appear to be pretty good numbers)?
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It isn't only theoretical. What a customer will notice is hard to say, however. Toughness is one of those properties where you have enough until you didn't.
It’s also interesting to me that there is common advice that if you don’t have precise heat treating equipment using a steel like 52100 would be no better and actually worse than using something else. However, the data here seems to show wandering off from “ideal” intentionally to test the range still resulted in better numbers than some of the ideals for other steels in the comparison chart. Would the concern be more with hold times than temp ranges (as there appeared to be some difference between the 10 and 15 minute samples potentially).
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None of these heat treatments were really outside of the "ideal" apart from maybe the 1450-1475°F austenitizing temperatures. However, those lower temperatures have often been recommended by knifemakers. But in general it is a good idea when conducting experiments to broaden your range some to make sure there isn't some effect that previously hasn't been accounted for.
 
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I followed the protocol from Larrin's 52100 article with the Divorced Eutectoid Transformation before Austenizing and the higher Austenizing temperture.


I must say, this is my new favorite protocol.
Very stable and tough but higher working hardness, Thanks Larrin
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Larrin said:
None of these heat treatments were really outside of the "ideal" apart from maybe the 1450-1475°F austenitizing temperatures. However, those lower temperatures have often been recommended by knifemakers. .
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Charpy tests , theory and paper are only one side of the medal , have you ever made knife from 52100 steel with your recommended protocol and test it ? I know knife maker from Serbia who use 52100 steel and he make many, many tests on KNIFE /not on square piece of hardened steel/ with different HT protocol and he come to conclusion that 800 Celsius is best for 52100 of course with his normalization procedure /“thermal cycles”/ after he forge knife .He constantly get 66-67 HRC after quench .....................There was are plenty video clip on tube where he test his knife ......as proof .
You can make one knife with your protocol and repeat his tests and then compare result .............
 
Natlek said:
Charpy tests , theory and paper are only one side of the medal , have you ever made knife from 52100 steel with your recommended protocol and test it ? I know knife maker from Serbia who use 52100 steel and he make many, many tests on KNIFE /not on square piece of hardened steel/ with different HT protocol and he come to conclusion that 800 Celsius is best for 52100 of course with his normalization procedure /“thermal cycles”/ after he forge knife .He constantly get 66-67 HRC after quench .....................There was are plenty video clip on tube where he test his knife ......as proof .
You can make one knife with your protocol and repeat his tests and then compare result .............
Click to expand...

No one cares what you think.

Hoss
 
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