heat treating 52100

scott.livesey

Dealer - Purveyor
hi,
bought a piece of 52100 from Aldo to use. went online to find some heat treat numbers. found some interesting articles. one looked at different alloys, 52100 vs 440c vs cpm9v.
http://digitalcommons.lmu.edu/cgi/v...ghsEQ#search="heat treatment sae 52100 steel" one looked at how hardening and tempering temperatures affected the steel.
http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0270415
for any science geeks(like me) out there, here are some links.
have a good day,
scott
 
Hello Scott , I had the same question . So I contacted a real expert in HT . Peters heat treat . Here is what he told me . You can ht both of those metals yourself ,except cpm9V. Bring it to full non magnetic and quench in oil . He said it will bring it to full hardness. temper 2 cycles at 1 hr each
worked great , I was totally surprised ? I thought all Stainless steels needed some special ht . I was wrong... Bubba
 
These are special application steels designed to perform specific tasks, in this case bearings. Thus they have specific windows of precise heat treatment that will unlock the full potential that was designed into them. Can you make them much harder simply by heating and quenching them? Yes you can, as you can with just about any steel with enough carbon to harden. Does this fall within the alloys optimum window? Nope, but it is more than enough to impress us with what the average knife does. Chopping, whittling, wood and cutting rope or paper impresses us but industry needs these alloys to do things on a whole other magnitude of specialized performance than what we can wrap our head around. I routinely see many knifemakers, who do their own heat treatment and use pretty much the same procedure for all steels, state that this steel or that doesn’t perform much different than W2 or 1084. This should come as no surprise since they treat all those other steels as if they were 1084.

The short of it would be, can you make a serviceable knife using any simple heat treatment with many of these specialized alloys? Yep, but they were designed to do much more impressive things when given the specific heat treatment they need.

The second paper did some curious things, like make loads of retained austenite and then zap it with freezing. Many knifemakers don't realize that they do the same when see see large increases in hardness when freezing simpler steels. It is more efficient to avoid the R.A. to begin with by keeping tight control on your heat.
 
I have to agree with kevin , although these are knives not specialised performance tools . I f it will chop, whittle cut wood rope or paper without dulling too much you have a good knife . I do keep a pretty tight control on heat , I just do it a different way . I saw Kevin and his buddy making a sword on PBS the other night
very good by the way . They were working with some very complex steel , How do you maintain tight control there ??? curious.
 
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Higher carbon is not "complex" in my book when compared to other alloying, other than the proeutectoid phases to deal with it is pretty straight forward in comparison, and if you have good patterning most of the proeutectoid phase is accounted for. Modern alloys designed for specific tasks and specific heat treatments to meet their unique chemistry and ancient simple iron-carbon metals in a blade; I think the heat treating considerations may be a little different.

As for the NOVA special, that was Ric's baby, Ric asked me to participate, he is a good friend and I did, but the film producers did not find me very easy to deal with in supporting their narrative and approach. I had nothing to do with the heat treatment, flaming quenches are not my thing. In fact, reveiw the video and watch closely as Ric moves from the forge to the quench outside, you will see me literally walk off the set behind him, that was the deal made by the film team to get me to even work the bellows in that shot. It is worth noting that I doubt Ric normally heat treats that way but you need to appeal to the entertainment aspects of television.

The whole project was a real education in how such films are made and how they can make just about anything with whatever they have by camera angles and editing, they are very good at what they do. The shoot took two days, that process would take weeks, I had to adjust to watching the final cut because it was all entirely out of sequence of when it was shot. Let's just say that nobody should assume they know how such a sword is made by watching the show, I know how both were made. Both Ric and the film crew are good at what they do and bits and pieces came together to make a very good T.V. show.
 
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You bet , quenching that sword made me nervous . I dont blame you for not watching .That was a great sword . I was as worried as he was .

I believe I could forge one of those . I have made crucible steel before. But, not from ore . I have made my own steel from scratch using Japanese black sand ore . From that a 7 piece Laminate soshi Kitae sword was made . I have about 500lbs of good black hematite and some
magnetite about 100lbs. Loved that hammer technique you fellas were using . Maybe we can get together sometime and make a nice sword
My old ass is getting near the end of my forging days , Old arthritus is gaining on me . Rotator cuff is torn right now . Orthopedic Dr . says
It will not get better by itself. The TV show was great ....... Bubba-san
 
Scott, eventually the plan is for me to finish the testing and supply Aldo with some heat treating specs that will be specifically geared for knifemakers for some of his more commonly offered steels on his website. Until then, I can say that you will want to normalize that particular 52100 at 1650F before proceeding with hardening. The stuff is very well spheroidized for machining operations and needs some of its carbon prepared for solution because of it. Once you do this, simply soak it at 1475F for around 10 minutes and quench in any medium speed oil. Avoid going beyond 1500F for any 52100 in knife blade applications as you will stabilize austenite and the Rockwell will suffer because of it.
 
Could have saved a bundle on extra strength aspirin..... but good to know now. Thanks Kevin. So is that normailzation 1650 - 1600 - 1550?

Rob!
 
psssst..... you cant say I didnt try..... Bubba

To the contrary, I think you did just fine, but there seems to be two different conversations occurring here, which indicates a bit of thread drift. Scott was looking for information on 52100 heat treatment and in the process found some literature dealing with very involved treatments of comparatively more complex alloys than 1% C and 1.4% Cr. I delved into that but thought I would offer what I could to Scott’s initial search since I do have some personal insights with that batch of 52100. Which brings us back to…

Could have saved a bundle on extra strength aspirin..... but good to know now. Thanks Kevin. So is that normailzation 1650 - 1600 - 1550?

Rob!

Rob and Darrin, you can handle subsequent treatments in any fashion your need for you process, but it is the one 1650F (or even a bit more) normalizing that is important. This particular run of 52100 states “95% spheroidal condition” in its analysis, and you better believe it. This is not a flaw or problem in the steel, it is intentional for easier machining, but the carbon is locked up very tight in large spheroidal carbide. Going straight to the hardening like this will get you 63 HRC at the most, no matter how hard you try. The high heat will dissolve more from these large spheroids and put it into more easily used structures. Just avoid slow cooling from above critical in these operations so that the freed carbon doesn’t go back into a problematic arrangements (like, heaven forbid, grain boundary networks). Just air cool as you would in normalizing, and not slow cool like you would for annealing.
 
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Kevin : question why would you want a blade rc higher than 63 ? or is that a hypothetical . You still up for that sword ........
 
I have just recently started working with Aldo's 52100 and a big thanks goes to Kevin Cashen for his info on the steel. I followed the info you messaged me Kevin and did my normalizing process starting at i think 1675deg. I have only done 2 knives so far like this and the quenching was done a little different for both. The first was a single quench with a soak time of i think 7min at 1475deg. I finished this knife out and sharpened it and did a rope cut test with it, results were 38cuts before it lost a shaving edge.

The second blade i did a "Fowler Type Quench". The heat treat was the same but i triple quenched the blade over a 3 day process with the knife resting each night in the freezer and the last night in a LN cryo bath. I have not done a cut test with this blade yet to see if i gained anything but i may get some time to do that today.

Thanks again Kevin for the info !!!

steve
 
Kevin : question why would you want a blade rc higher than 63 ? or is that a hypothetical . You still up for that sword ........

Since 52100 is easily capable of 65+ out of the quench, 63HRC would mean you didn't fully harden it. 63HRC as quenched on 5160 would be peachy, but with 52100 it means the current heat treatment isn't working. I have gotten 67HRC from the quench with 52100 by the previously mentioned soak (1475F) temps, I would take it every time if I could, but less than 64 as quenched would be unnaceptable in my shop. Well, that is, if I regularly worked with 52100.

We make different kinds of swords Bubba. One couldn't pay me, and folks try all the time, to make another katana. And the swords I do make have to be all mine, can't stamp it if it is not, and I need to devote my limited time to the ones folks have payed me for.
 
I have just recently started working with Aldo's 52100 and a big thanks goes to Kevin Cashen for his info on the steel. I followed the info you messaged me Kevin and did my normalizing process starting at i think 1675deg...

I may still have some micrographs of that 52100 on my lab computer, but they weren't publishing quality (I don't get rid of all the scratches when I just need to check things out for my own info). The spheroids were very large and regular, even after a normal quench. Dissolving them a bit allows later heat treatments to use what is needed for hardness and helps put them into much finer spheroids that will make for a fine edge that can handle wear more evenly.
 
Kevin, what is your overall opinion of using 52100 for knife blades? I've messed with it a bit. When I did some marquenching with it, and we've discussed the problems with using something like peanut oil instead of marquenching oil for the process, and I got a very strong blade that I had to beat the heck out of with a 4 lb hammer to get it to break. I did some isothermal quenching with another, quick quench at 350° to give about 75% martensite according to the IT diagram and then up quenched to 430° for four hours to convert the rest to lower bainite. That gave me a blade that almost bent to 90° before breaking and that might be from the stamp serving as a stress riser as it broke right through that area. I had also just went from the forge to the 430° oil bath and got a blade that would cut well and bent to 90° without even cracking the edge but it held the 90° bend. The first two were able to chop through a 2X4 and still shaved hair. The last one was too short for chopping, about 3.5" but it cut well.

The reason that I'm asking about this is that even though 52100 seems to be a very flexible steel in it's heat treating potential, because of my rather basic heat treating equipment, I'm wondering if I would be better off sticking with something like 9260.

Doug
 
Kevin, what is your overall opinion of using 52100 for knife blades? ...

...The reason that I'm asking about this is that even though 52100 seems to be a very flexible steel in it's heat treating potential, because of my rather basic heat treating equipment, I'm wondering if I would be better off sticking with something like 9260.

Doug

Wow, this place is dead for weeks and then comes alive in a day. Perhaps it not just here that it is such a cold rainy Saturday that one can’t force themselves out to the shop, I’m freezing even indoors.

My opinion is just that- opinion. I don’t put too much stock in pure opinion so I would have a hard time asking others to regard mine differently. I have found steels that give me what I want for my purposes that aren’t nearly as quirky. I do consider it a simple steel (1.4% Cr is not much in alloying when compared to say L6, which name comes from “Low alloy”), and yet for such a simple steel it is quirky as all get out if you don’t work it by its rather finicky rules. I mostly use 52100 for metallographic studies because one can so easily produce so many of the problematic issues with it. It is not a steel well matched for simple equipment not capable of holding tight temperature tolerances, and this is evident in all of the odd assortment of unique heat treatments bladesmiths have come up with to make it perform. Part of this may be because it is so specialized in its design and purpose as a bearing steel, bringing out properties for a knife requires altering the treatments that it was designed for as bearings.

It is a high strength, abrasion resistant, alloy, thus its dominant hypereutectoid nature, so it would naturally work best in fine slicers and cutters where fine edge holding is desirable. To force it into a large chopper that requires high toughness would be sacrificing it finest qualities. So I would say if you want to make skinners, scalpels, razors etc… learning to work with it may be worth the trouble, if you want to make machetes, bowies, camp knives etc… and you like the 9260, then go for it.

I am a strong proponent of the idea of not juggling so many steels that you never really get the hang of any of them. Sticking with a steel and really getting to know is the most direct route to success, but that has to be tempered with the knowledge that one steel cannot serve all functions. So I think it is advisable that at the very least you choose two, one for fine edge stability and one for tough chopping and cleaving. The two you choose should probably best match your ability to meet their heat treating demands.

I guess that would be my best educated opinion.
 
Scott, eventually the plan is for me to finish the testing and supply Aldo with some heat treating specs that will be specifically geared for knifemakers for some of his more commonly offered steels on his website. Until then, I can say that you will want to normalize that particular 52100 at 1650F before proceeding with hardening. The stuff is very well spheroidized for machining operations and needs some of its carbon prepared for solution because of it. Once you do this, simply soak it at 1475F for around 10 minutes and quench in any medium speed oil. Avoid going beyond 1500F for any 52100 in knife blade applications as you will stabilize austenite and the Rockwell will suffer because of it.
thanks for the info Kevin. Is +/- 25 degrees F tight enough temperature control? that is about the best i can hope for in my little manual lab furnace with analog temperature gauge. the steel is for small (3 to 4 inch) paring/utility knives. How long a soak time at 1650F when normalizing? i dont have access to liquid nitrogen, would dry ice and acetone bath be worthwhile?
wasn't trying to stir the pot, although i like seeing the many comments. did anyone notice the date on the second document, the one dealing with just 52100? it was published in 1960 and when first published may have been classified.
do you have any heat treat info to give on Aldo's current batch of 15N20? if you don't, would it heat treat similar to L6?
thank you again for your help.
scott
 
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Kevin , I missunderstood you . I though 63 was the tempered blade . No big deal about the sword , I do have some nice tamahagane billets
we made these a couple years back . I was saving them for a worthy project . I have a Japanese friend and swordsmith who makes medieval swords from japanese steel ! now thats a switch for you . He has a special ht and temper that leaves it very springy , they are through hardened no clay.
I like 52100 as a core for sanmai . As a matter of fact I made about 10 of them for retail sale . One is posted on my page . I think it is one of the better knife steels around , however it can be difficult to work . It also takes a good durable edge . I did have some trouble making it stick to high carbon Damascus . The damascus would move but the 52100 would just barely move . Problem was I did not normalize it enough . Once I figured that out , everything worked fine . It is my preference for smaller blades . Not a big fan of stainless , give me carbon steel . Bubba
 
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