Widney Burton Posted January 25, 2021 Share Posted January 25, 2021 New maker, here. I am working on an order that is a 52100 12 inch long, 3/16 inch thick Bowie styled blade. I do alot of my research and studying on youtube (it's just how I learn best) watching videos made by reputable knife makers (i.e. Jason Knight, Kyle Royer, Fire Creek Forge, etc.) And their processes of working with certain types of steel and so on. I saw that on one of the videos I had studied for 52100 steel, the maker heat treated, cryo treated and then tempered. My reason for posting this, is to obtain a detailed proper description on the steps taken to complete this process. I use a homemade coal forge that gets more than hot enough to attain fairly controllable heat treat temps for doing my own heat treatments (I will soon be upgrading my entire setup to an actual professional level very soon, I know that my described setup isn't really ideal). The cryogenic treatment was achieved with dry ice and ethanol and I would like to use this method to acquire a few extra points of hardness in this 52100 knife and give my customer a super strong blade. If this is the wrong place to post this, I apologize. Please let me know where to move it to or where to go to read about this specific process, if that is indeed the case. Thanks!! Link to comment Share on other sites More sharing options...
Alex Middleton Posted January 25, 2021 Share Posted January 25, 2021 I'm not certain that 52100 is improved much by a cryo treatment. I could very well be incorrect though. Here's a link to Kevin Cashens' page where he details his 52100 heat treat sequence. It may not be exactly what you're looking for, but hopefully it helps. http://www.cashenblades.com/steel/52100.html 1 1 Link to comment Share on other sites More sharing options...
Jaro Petrina Posted January 25, 2021 Share Posted January 25, 2021 I would think that its the toughness, rather than hardness, that is improved by the cryo. 1 Link to comment Share on other sites More sharing options...
Alan Longmire Posted January 25, 2021 Share Posted January 25, 2021 The best thing to do for toughness in 52100 is multiple normalization cycles. Like, seven or eight. Most steels reach a point of diminishing returns after three, but you can take the grain of 52100 down finer than industry checks for in addition to making the carbides smaller. I also don't think dry ice cryo will do a lot for this steel. Liquid nitrogen might add some toughness and maybe a point of hardness. 2 Link to comment Share on other sites More sharing options...
Widney Burton Posted January 25, 2021 Author Share Posted January 25, 2021 I absolutely appreciate the quick replies. Now it makes sense why I couldn't find any videos on dry ice cryo treating 52100 steel lol Link to comment Share on other sites More sharing options...
Jerrod Miller Posted January 25, 2021 Share Posted January 25, 2021 I don't play with 52100 too much, so I had to look it up a little bit. The ASM Heat Treater's Guide mentions that aerospace tends to use refrigeration (-95F or lower) with this alloy. You do this immediately after an oil/polymer quench and keep it cold for at least an hour. Then slowly warm to room temp, then temper. This isn't really that commonly done because there is very little retained austenite to convert. 90% martensite conversion is done by about 325F, so we are darn near 100% by the time we are room temp. And yes, this was the correct sub-forum. 1 Link to comment Share on other sites More sharing options...
HSJackson Posted January 25, 2021 Share Posted January 25, 2021 The late Al Pendray was a proponent of austempering 52100 by quenching into 500F salts for 30 min or so and then air cooling to room temp. Supposedly made tougher steel for a given hardness. Here's an article on austempering: https://knifesteelnerds.com/2018/07/09/bainite-vs-martensite/ 1 Link to comment Share on other sites More sharing options...
Gerhard Gerber Posted January 26, 2021 Share Posted January 26, 2021 20 hours ago, Alan Longmire said: The best thing to do for toughness in 52100 is multiple normalization cycles. Like, seven or eight. Most steels reach a point of diminishing returns after three, but you can take the grain of 52100 down finer than industry checks for in addition to making the carbides smaller. I also don't think dry ice cryo will do a lot for this steel. Liquid nitrogen might add some toughness and maybe a point of hardness. I use 52100 a lot, I have a bucket full of Timken bearing races...... I always normalize, but 2 or 3 times max. Eight times? What temperatures do you use? I would be scared of cooking all the carbon out. Another vote for for Kevin Cashen's site, my go-to reference. Link to comment Share on other sites More sharing options...
Alan Longmire Posted January 26, 2021 Share Posted January 26, 2021 The guy who taught me about 52100 did a series of tests on 52100 from flattened ball bearings. As-forged, the grain was what industry calls a 3. I don't know what the units are, but they grade grain from coarse to fine on a scale of 1 to 10, with 10 being the finest, the ideal you see in a broken file. After three normalizations, the grain was a 9. After eight, the metallurgist who was looking at it said "It's off the scale, but I'd call it maybe a 13?" Temperature was estimated by decalescence in a gas-fired drum forge. The steel was allowed to cool to black as seen in a bucket painted black in dim light, then taken just to decalescence again. He made a competition cutter from that batch that outcut anything I've seen. He even took a chunk out of the 6mm thick mild steel tabletop during the water bottle cut. The chip out of the edge of the steel tabletop was a clean cut about 20mm long and three mm deep in the center. The knife had no discernable damage or loss of sharpness. Decarb is not an issue in a reducing atmosphere. That said, knowing you have an electric furnace, this same guy bought an electric furnace and had to completely redo his HT methods. Lost a lot of blades before he realized he needed anti-scale powder or HT foil. So yes, you are right to worry about decarb with your setup! 2 Link to comment Share on other sites More sharing options...
Jerrod Miller Posted January 26, 2021 Share Posted January 26, 2021 (edited) On 1/26/2021 at 10:26 AM, Alan Longmire said: I don't know what the units are, but they grade grain from coarse to fine on a scale of 1 to 10, with 10 being the finest, the ideal you see in a broken file. I do! It is based on the number of grains per unit of area, as measured in an optical microscope. This is done by polishing a cross-section and etching it, then going in and taking a look and actually counting grains. It is only really a valid number when the grains are relatively uniform in size and distribution. The old formulation was N = 2^(n-1), where N is the number of grains counted at 100x magnification per square inch, and n is the ASTM grain size number. My understanding is that there is a new formula, n = (3.321928*log10(N))-2.954 where n is the grain size number, but now N is the number of grains counted at 1X in 1mm^2. This appears to be covered by ASTM E112, which I do not have a copy of because we do not use it. Therefore a grain size number of 10 would indicate about 7,500 grains per square mm. That is why it looks so smooth. Using the older formula we would get 512 grains per in^2 at 100X magnification. I like the older way because it is far less counting. Then again, it is often done with software now, and computers can count pretty high pretty fast. Doing it manually involves more math, because you aren't really looking at a set sized area of 1 in^2 or 1mm^2. More info on the Olympus website. Edited December 2, 2022 by Jerrod Miller 2 Link to comment Share on other sites More sharing options...
Alan Longmire Posted January 26, 2021 Share Posted January 26, 2021 I was hoping you'd chime in, since I know you knew what the numbers actually mean. Thanks! Link to comment Share on other sites More sharing options...
Gerhard Gerber Posted January 28, 2021 Share Posted January 28, 2021 Yet again why I love this place..... @Alan Longmire I know I did good heat treats in my charcoal forge with a pipe, time and usage has shown that. I love the accuracy of the kiln, removes any doubt, but reading this reinforces a feeling I've had for a while that I should get a secondary (most likely gas) forge for heat treating, or maybe a charcoal forge specifically for longer blades. Thank you for sharing that very interesting bit of information. Link to comment Share on other sites More sharing options...
Widney Burton Posted January 28, 2021 Author Share Posted January 28, 2021 Thank you all, for sharing this invaluable knowledge on this thread. I have found that my first try working with 52100 and putting your advice into practice in my coal forge worked out beautifully! I still have some scrap 52100 that I'm going to cut up into 3 inch pieces and do some testing with heat treat processes. Its easily my new favorite blade steel! Link to comment Share on other sites More sharing options...
Widney Burton Posted January 28, 2021 Author Share Posted January 28, 2021 This is the 52100 blade that I have been working on since posting this question. I have heat treated and profiled and am now hand sanding and polishing. Its 3/16 thick, 12 inches long and 1 1/4 wide. I tempered at 350 for 2 one and a half hour cycles. Link to comment Share on other sites More sharing options...
Gerhard Gerber Posted January 28, 2021 Share Posted January 28, 2021 @Widney Burton it is an amazing steel, and nothing else I've experienced take such a beautiful dark & durable coffee etch. 1 1 Link to comment Share on other sites More sharing options...
Widney Burton Posted January 28, 2021 Author Share Posted January 28, 2021 (edited) 6 hours ago, Gerhard Gerber said: @Widney Burton it is an amazing steel, and nothing else I've experienced take such a beautiful dark & durable coffee etch. I was actually gonna etch this blade to make the spine very dark and the bevels bright. Good to know that it takes on a good etch! Edited January 28, 2021 by Widney Burton Misspelling Link to comment Share on other sites More sharing options...
Kreg Whitehead Posted January 29, 2021 Share Posted January 29, 2021 I just heat treated some of the barrons 52100 last night. Normalized it and thermal cycled it 5 times. There is a small tail(for lack of a better word) below the ricasso.....I do that on purpose because it helps me keep my plunge lines crisper. Its only about 3/4"x3/4". I am gonna cut it off and attempt to snap it. If I am successful I will post some pics. Any suggestions on trying to break something that small? I have NOT tempered it yet....and was just thinking of putting it in the vise horizontally the hitting it in the center with a hammer and chisel. Link to comment Share on other sites More sharing options...
Alan Longmire Posted January 29, 2021 Share Posted January 29, 2021 That ought to work, but wear your safety glasses! I'd also put tape on both sides of the 52100, that way you may have a chance of finding it after it breaks. Link to comment Share on other sites More sharing options...
Kreg Whitehead Posted February 2, 2021 Share Posted February 2, 2021 Just so ya guys dont think I am a flake......I tried for 20 min to snap that piece last night. It is pretty small.....by the time I cut it off the blade it was/is more like 1/2" x 3/8" Link to comment Share on other sites More sharing options...
Widney Burton Posted February 2, 2021 Author Share Posted February 2, 2021 Were you successful in snapping that small piece? I was going to say use a hammer and your vise but I never would have thought to tape it lol that's good thinking. I think I'm going to start leaving a piece of extra steel sticking off the side of all of my blades from now on to cut off and try snapping after I heat treat them. Thats a great idea to get data on my blades heat treatment! Link to comment Share on other sites More sharing options...
Kreg Whitehead Posted February 2, 2021 Share Posted February 2, 2021 2 hours ago, Widney Burton said: Were you successful in snapping that small piece? I was going to say use a hammer and your vise but I never would have thought to tape it lol that's good thinking. I think I'm going to start leaving a piece of extra steel sticking off the side of all of my blades from now on to cut off and try snapping after I heat treat them. Thats a great idea to get data on my blades heat treatment! Horizontal in the vice I just kept knocking through the vice. Put it in vertically .....tightened the vice as tight as I could......and ended up knocking it outta the vice several times. I though not being tempered it would snap fairly easily. I was wrong. lol Link to comment Share on other sites More sharing options...
Alan Longmire Posted February 2, 2021 Share Posted February 2, 2021 Well, it is pretty tough steel... I'd have thought that horizontal with a small gap between the jaws, struck hard with a blunt chisel would do it, though. Or maybe not! Link to comment Share on other sites More sharing options...
Conan Dunlap Posted January 4, 2022 Share Posted January 4, 2022 I am making a hunter in 52100, and I was looking for Kevin Cashen's heat treating info on this, and everywhere just links to his site, but the page comes up as page not found. Does anyone have the actual temperatures for the normalization and quenching? Link to comment Share on other sites More sharing options...
Jerrod Miller Posted January 4, 2022 Share Posted January 4, 2022 11 minutes ago, Conan Dunlap said: I am making a hunter in 52100, and I was looking for Kevin Cashen's heat treating info on this, and everywhere just links to his site, but the page comes up as page not found. Does anyone have the actual temperatures for the normalization and quenching? I went to his website (https://cashenblades.com) and was able to navigate to his 52100 section that has his HT recommendations (https://cashenblades.com/2021/02/08/52100/). As you can see in that hyperlink, the date of 2021/02/08 is included, so I imagine he may change that every time it is updated and thus the broken links you are finding. When in doubt, just go to the main page and navigate through. From the home page I just scrolled down and saw a link for "steels" near the bottom. That led to a page that had a link for "52100". Link to comment Share on other sites More sharing options...
Conan Dunlap Posted January 4, 2022 Share Posted January 4, 2022 3 minutes ago, Jerrod Miller said: I went to his website (https://cashenblades.com) and was able to navigate to his 52100 section that has his HT recommendations (https://cashenblades.com/2021/02/08/52100/). As you can see in that hyperlink, the date of 2021/02/08 is included, so I imagine he may change that every time it is updated and thus the broken links you are finding. When in doubt, just go to the main page and navigate through. From the home page I just scrolled down and saw a link for "steels" near the bottom. That led to a page that had a link for "52100". Thanks, I don't know why I couldn't find that the first time. Link to comment Share on other sites More sharing options...
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