Low alloy steels typically used by forging bladesmiths can have good toughness but the wear resistance and edge retention is relatively low due to the lack of hard carbides. Bravo! However, you can often use a lower tempering temperature to achieve the same hardness with a lower austenitizing temperature. This test is not perfect for our purposes since we are testing edge retention with a slice but the sharpness is measured with a push cut. However, even when holding sharpening constant there are other important properties, such as toughness, ease in sharpening, corrosion resistance, etc. Aogami isn’t designed for this… rex 121 is not designed for that… that is life…. One, the consistency of the CATRA paper is not great from batch to batch. 2) The tungsten carbides observed in the micrographs of Blue Super and 1.2562 were relatively large and widely apart from each other, so perhaps the carbides were so dispersed that they did not consistently contribute to the edge. A relatively coarse 400 grit was chosen because, when slicing, a coarser finish leads to superior edge retention due to the “micro-serrated” nature of the edge, a fact which has been pointed out by many people performing tests when slicing materials like rope, such as Cliff Stamp [2], Jim Ankerson [3], and Phil Wilson [4]. [1] https://scienceofsharp.com/2015/03/01/the-diamond-plate-progression/, [2] http://www.cliffstamp.com/knives/articles/grits.html, [3] https://www.bladeforums.com/threads/ranking-of-steels-in-categories-based-on-edge-retention-cutting-5-8-rope.793481/, [4] http://seamountknifeworks.com/js/web/viewer.html?file=articles/pdf/shapening.pdf, [5] http://www.matweb.com/search/datasheet.aspx?matguid=8715a9d3d1a149babe853b465c79f73e&n=1&ckck=1. In previous articles I generated this regression equation based on the contribution of edge angle, steel hardness, and volume of each carbide type. In short, Cruwear is the most balanced of the 3 (balance between stain resistance, edge durability, and edge retention). They got nearly the same TCC with handsharpened Global blades as you did with REX 121… ? After 120 strokes (60 back and forth “cycles”) the test is complete and the total amount of paper is added up, called the Total Cardstock Cut (TCC) reported in mm. Slicing Edge Retention and Wear Resistance. So I’m happy it made sense to somebody. If we remove the non-stainless steels and look at stainless alone, the toughness-wear resistance balance is in general a bit lower. However, the 0.1% nitrogen in 14C28N is not enough to lead to a significant change to the chromium carbides. The CATRA machine generates sharpness loss curves as it tests and those are all saved. Each knife was tested three times on the CATRA edge retention tester and the results averaged. And we will hopefully add more steels and look at other things in the future. These knives include kitchen knives, straight razors, and fine slicers. In general, a higher austenitizing temperature leads to more carbon in solution and higher hardness. For many steels they may have multiple names despite being identical such as PD#1 and Z-Wear being the same as CPM CruWear. This may be because of the 100°F higher austenitizing temperature which leads to more carbide dissolution. These steels form the high hardness WC tungsten carbide which isn’t found in other high alloy tungsten steels like high speed steels. with vanadium rich steels like sg2 to 15V. Sorry rubbish … They did not say anything about grit or geometrie, but at least a Global has a worse geometry for test`s like this. Great report! But some claim other effects like an increase in carbides which are not likely given the cryogenic temperatures involved. Ankerson Knife and Computer Geek Platinum Member. For the steels which were tested at multiple hardness levels I have dots connected by lines. My question is this: since you didn’t test 1084 (I totally understand why, there’s little variation in the LA steels), could you give an estimate on the edge retention of it compared to 1095 or O1? Thanks for watching!If you want to skip the cardboard cutting and get to the results skip ahead to about 11:00. The dataset used for those predictions had very few high speed steels which is also the case with this dataset. I joke I joke. You can read more about the austenitizing step in heat treating in these articles: Part 1, Part 2, and Part 3. i wish you luck finding another material with a test result confirmed abrasive content i hope you do. We compared CPM-4V with a temper of 400°F and 1000°F. However, we have seen relatively large improvements in toughness by using 400°F tempers with CPM CruWear and CPM-4V which I think makes the low temper more desirable. My point is simply that sometimes some steels (with ht & knife design being equal) are simply better than others at certain tasks and this data suggests aogami isn’t as good as most on this list. Therefore, having only hard vanadium carbides leads to the best level of toughness for a given level of wear resistance/edge retention. It could be that the M6C (tungsten/molydenum carbides) present in high speed steels contribute more to edge retention than previously found. A stack of paper stock with 5% silica (sand) in it is lowered onto a knife with a fixed load (50 Newtons) and the knife is moved back and forth. Z-Max did a bit better than predicted when looking at the edge retention predictions based on carbide content. I’ve seen the same testing and using japanese tools with blue 1 and blue super. Based on the used edge of both knives it looks like the steel isn’t hard enough to handle the 20 degree edge and therefore is deforming. The carbides in CPM-154 are of course smaller than 154CM but are still larger than the carbides in Vanax and S110V. Certainly nothing to the extent of 3x or 6.5x improvements in wear resistance. I expected a bit more separation between 4V and CPM-CruWear because the two have similar carbide content, but 4V is entirely vanadium carbide while CPM-CruWear has a mix between the two. Global did… 15-20 degree per side. It could be that the sand abrasive is too hard to differentiate between low alloy steels though. Notify me of follow-up comments by email. Comparisons between the silica size and carbide size is not easy as the distribution is somewhat complex; the median silica size is less than 2 microns but the average is about 8 microns. How do you think the results would differ, if instead, the test was done to a specific BESS rating (maybe around 600 or so)? AEB-L is the same as 13C26. In my Part 3 article I concluded that those cryo articles “are not very convincing” when talking about wear resistance improvements and after doing a study myself I am even less convinced. Less carbide means lower edge retention as discussed ad nauseam in this article so far. Metallurgy and Testing of Knives and Steel. It is used extensively in the manufacturing of ball bearings and in applications where corrosion is less of an issue. After I heat treated and surface ground all of the blanks, I shipped them to knifemaker Shawn Houston of Triple B Handmade (Big Brown Bear) who ground the bevels and put the initial edge on the knives. If anything it was slightly negative: I don’t think the cementite is actually reducing edge retention. However, Vanax did not do quite as well as S30V in edge retention. s110v may have some of the best edge retention? There is a vague reference in the ISO standard that talks about not using the first 25 mm in a paper stack. Its fine grain helps it get, https://www.bladeforums.com/threads/bladeforums-has-a-zero-tolerance-policy-towards-threats-of-violence-extremism-be-warned.1769537/, (You must log in or sign up to reply here. Low alloy steels did relatively poorly for edge retention, with 8670 and 52100 being the most balanced. Unfortunately the 440C toughness specimens I was going to test were ruined in machining. Also the paper comes loose as 10mm wide strips, and they must be stacked together by hand and inserted into the machine which is somewhat tedious. Your email address will not be published. 52100 is the most fun to sharpen and play with, and M4 is the beast with the best long term edge retention. Based on the hardness of the carbides I also said that I expected iron carbide, called cementite (M3C or Fe3C), to have a contribution of about 5, ie 5*M3C. When comparing steels I like to look at the balance between toughness and edge retention, as those are two very important properties that are often opposed to each other. Keep up the great work. This article was already too long to look at individual tests. I then got the tester in mid-January and my excitement was tempered (amazing heat treating pun) a bit. 20,867. I also used the toughness value of Maxamet for Z-Max despite being different steels because they are in a similar class of steel and the very high hardness steels don’t vary much. In general, I didn’t change the austenitizing temperature much when comparing the same steel at different hardness so the trend of hardness vs edge retention looks about right for steels like S30V and 10V. AISI 52100 is a high carbon tool steel containing low quantities of manganese and chromium to improve hardening. In this study I chose D2 steel because it has had more cryo research done on it than any other steel. Did I just make up a word? It is also difficult to avoid high levels of retained austenite when heat treating them. I love the way they perform on field dressing game and camp use. We decided on a 400 grit (40 micron) “metallic bonded” CBN stone, meaning the CBN abrasive is throughout a metallic matrix rather than a CBN coating over a plate. Stropability? At this point I haven’t measured enough of an improvement in edge retention with the vanadium/tungsten-alloyed steels like 1.2519, CruForgeV, 1.2562. He uses a slow quench oil and apparently gets good hardness and edge retention even with the extreme grain refinement. SG2 isn’t cheap but it is stainless and cuts far better than the blue super. Edge stability is a property that describes a steel's ability to hold a finely sharpened edge. Perhaps vanadium nitride is not as hard as vanadium carbide or not as effective at contributing to edge retention. 14c28n is stainless, tougher, cheaper, and is better at cutting card stock:) If you think that is an invalid assumption then you can ignore anything labeled Z-Max. Unlike the 440 grades, however, all three AUS grades have vanadium alloyed to increase wear resistance and edge retention. The knife cuts into the paper which allows the head to lower, the distance the head lowers is recorded for every “cut” of the knife. The only steel which isn’t a low-chromium vanadium-alloyed powder metallurgy steel is 8670 which has very high toughness but relatively poor edge retention. Hey Larrin, thank you very much for the efford you are sharing with the knife community! I was targeting 61-62 Rc for most of the knives apart from a few that are basically never used at that hardness, such as ZDP-189, Rex 86, Rex 121, 1.2562, and Blue Super. We sharpened the knives to 30° (15 dps). How many tempering cycles were done in case of high speed steels (M2, CPM-M4)? I’m expecting less than 1095 but more than O1. Evidence against this hypothesis includes the fact that 1.2519, with its 1.2% Cr did not perform as well as 52100. ZDP-189 and Cowry-X are very similar. I don’t really know the reason for this reduced edge retention compared with S90V. 52100 is some tough stuff. This is really a step stone in scientific cutlery approach and I am sure not only amateurs will study it closely… simply the best article for me to date . However, this was only one test, and looking at the scatter in the results above you could conclude either low or high tempering is superior based on which two points you choose. The 1/8″ hole was used for convenience such as to thread wire through before dipping in liquid nitrogen in the heat treatment process. I think your information balancing the various properties of the “super steels” is a really useful antidote to all the marketing. You can read about these two different tempering regimes in this article on tempering. 52100 tool steel is considered an ideal, affordable alloy offering a very fine grain with superior edge retention. Feb 17, 2013 #15 did some more backtracking and think i have found the answers. Once all of those things were fixed and I was ready to run it for the first time, a “shaft coupler” decided to break. I plotted vs micron rather than grit because of the many different grit systems which leads to more confusion than anything. Perhaps the extra 0.3% Cr in 52100 was enough to make a difference. Perhaps it was enough to make the cementite harder than the silica in the paper. Do you think this is caused by some subcontious bias, statistical fluctuation, “human hand vs machine” reasons, or just other factors that are not regarded in the CATRA test? If you choose 5160 over 420HC, it's likely for aesthetics (you like a patina) or collectability more than performance in edge-retention. A cryo treatment can reduce retained austenite and increase hardness somewhat which can improve edge retention. The wear resistance and hard steel make for a better edge retention, it can hold an edge for a long time. Less carbon and alloy than either 1095 or O1 means lower wear resistance than either. However, using different test media may lead to somewhat different results in certain scenarios; low alloy steels with cementite may be one of those, we will see. The machine is surprisingly complicated but at the same time it performs a relatively simple task. But it would take a suicidal metallurgist to propose that the previous 100 years of wear resistance testing was wrong and that my next test is going to show the truth. Here is the result of that prediction equation vs what was measured in this study: The trend is very good, with the biggest deviations being Z-Max (high) and Blue Super and 1.2562 (low). The sensor that detects when it has run out of test media was no longer reading correctly. Your next box of paper may or may not come from the same lot of paper, so it may or may not have the same calibration factor. Also, do you think a less aggressive test media might favor different attributes that contribute to edge retention? 52100 Ball Bearing Steel is a high carbon steel with excellent wear resistance and strength.52100 is a mixture of high Carbon that is low in Chromium, which offers excellent wear resistance and edge retention.52100 is very hard steel, ours is tempered to 58-60HRC. So a 400 grit stone was chosen to use a finish which is more optimized for slicing without going crazy with something very coarse like 120 grit which is somewhat unlikely to be used by most knife owners. Can CATRA Predict Rope Cutting Performance? I thought they would do closer to the 400-450 mm range based on reports of wear resistance of the similar F2 steel in the old Tool Steels book. Enter your email address to subscribe to this blog and receive notifications of new posts by email. When I learned I would be getting the edge retention tester, I took just about every knife steel that I had and started heat treating a set of blanks for testing. I will address these along with other small deviations below. Surprisingly, LC200N and 14C28N did a small notch better than AEB-L and Nitro-V. LC200N does have chromium nitrides or at least “carbonitrides” rather than chromium carbides so perhaps those are higher in hardness leading to somewhat better edge retention. The edge retention was reduced with higher levels of polish. The edge finish is dictated by the type of cutting, and the edge angle is dictated by the steel and heat treatment and the user and his cutting. if this paper is made up for just that consistent results . S110V did worse than S90V despite being a similar steel but with higher carbon, chromium, and niobium, which should result in more carbide and more high hardness carbides. I will be writing about that more in a future article. Diamond&CBN vs AlO3 They line up with my experience as well. Unlike when slicing, with push cutting, a higher polish is superior because of the higher potential sharpness and the reduced resistance when pushing the knife through the material. I would decide if you want better edge retention at the cost of more difficult sharpening, or if you want an easier to sharpen steel that gets stupid sharp with minimal effort but doesn't have an amazing working edge. The above is for a range of vanadium-alloyed steels including stainless and non-stainless tool steels. Nov 2, 2002. Great article! 52100 Ball Bearing Steel is a high carbon steel with excellent wear resistance and strength.52100 is a mixture of high Carbon that is low in Chromium, which offers excellent wear resistance and edge retention.52100 is very hard steel, ours is tempered to 58-60HRC. In general, I didn’t test steels which have identical composition, so 204P represents values of M390 and 20CV as well. Since, most users (I guess it would be enthusiasts, ahhaha) of knives would likely never reach the point that CATRA testing creates. For those that don’t care about all of the individual details I recommend looking at the big comparison chart. You can use just one of these methods, or combine them. This is simply the most exhaustive study made available to the public without any commercial bias. If he is making push cuts then the coarse edge is a poor choice. Technically any media of an appropriate size could be put in rather than the standard silica-impregnated paper but thus far I have only used the paper. Then Amazon sent me the wrong one. The biggest differences in ease in sharpening were instead with burr removal. 0. If someone reads an article on CATRA testing and then says, “so now I make my chopping knives with 15 degree edges and sharpen them to 120 grit” then he misunderstands the type of cutting that will be performed and how to optimize for it. I also included tables with carbide contents of a range of different steels in Part 1 and Part 2. This can be seen in the previous charts showing that the steels with only vanadium carbide have higher edge retention for a given amount of carbide. Thanks for sharing your work with us! Other materials may behave differently which is why I’m exploring other media to see what differences may or may not arise. Do you have (or did you develop over the course of the last few months) a favorite method/technique for deburring? The high nitrogen steels Vanax and Vancron are primarily promoted by Uddeholm for their high adhesive wear resistance rather than abrasion resistance. I'm not a knife maker but I do have several Marble knives made in 52100. Part 3 is the most relevant to this discussion as it covers differences in wear resistance from cryo. Hey Larrin, Great work. Here is a summary chart of different carbide types: Measuring the hardness of carbides is difficult experimentally and some sources vary. improvement of at least 100%. 52100 edge retention Discussion in 'General Knife Discussion' started by shinyedges, Oct 23, 2014. Thanks a lot! I asked if they could pay me with the old CATRA tester rather than with money. For example, I have seen some papers report a hardness of 1800 Hv for M6C rather than 1400, which might be a better result as I will discuss below. Optimal steels include AEB-L and 52100. Stainless steels AEB-L, 14C28N and LC200N are pretty balanced at the lower end of the edge retention spectrum but most of the other stainless steels top out at relatively low toughness which limits their properties when compared to the non-stainless steels. Thanks to Trevor Welch, Theo N, Guns N’ Loaded, EV.Knives, Erik Coccia, Francisco J. Neto, Tristan, Gareth Chen, Alvise Miotti Bettanini, Henjie Taguinod, ben horridge, Steven, and Ian Miller for becoming Knife Steel Nerds Patreon supporters! You really need a controlled oven to get consistently good results with it. It holds a good edge and is fairly easy to resharpen. A couple things to watch out for as you do more testing. I thought it was there because it wasn’t one of the ones listed as not having a sample for. Many sources show silica as being higher in hardness than cementite [5]. Attribute #1: Edge retention & stability. There are probably others I’m forgetting but hopefully that’s enough for now. Abrasion is the mechanism by which we expect the edges to wear so perhaps that explains the difference. On the other hand, some components of the machine are simpler than I would have thought. A knife edge retention tester in itself is not necessarily useful without a good set of experiments to perform on it. To maintain precise angles, an Edge Pro was used and the resulting angle was checked with a laser goniometer. Paid Subscribers don't see ads! It would be interesting to see if the edge retention performance evens out relative to the high vanadium carbine steels, after the grind is optimized for each steel. In the CPM-154/154CM CATRA article we compared cryo vs non-cryo and no difference was found, but that was with high temperature tempering (~1000°F) which some claim does not result in an improvement from cryo. Page 3 of 3 < Prev 1 2 3. It has high toughness and good edge retention all across the normal range of hardnesses we expect from knife blades... since it has such a nice internal structure, I see no reason not to run it on the harder side (60Rc or perhaps even higher) to get the most wear-resistance while still having a good tough blade. The sensor that detects whether the cardstock clamp is in position was not functioning. In operation since 1998, BladeForums.com has led the industry since Day 1. This is probably the most important metric if you consider a knife’s core purpose to cut. When I tested my first group of plane irons and produced a data set, there was some static from a subset of folks who believe firmly that the purest tamahagane will outlast everything, and the purer blade steels (shirogami/aogami) are right on their heels if forged and then everything else is later.