Myths about End Properties after Heat Treating. Using liquid ntirogen with the same hardening temperature gets about 63.5 Rc as-quenched. To test the steel and see if has hardened correctly, take a file and scrape the corner of the file across the knife. I have a feeling that this article isn’t going to make much of a dent in the sharing of myths but I’m doing my best. “Simple” carbon steels also have retained austenite and are affected by cold treatments. Those formation temperatures are controlled by the steel composition and also the heat treatment, as higher hardening temperatures put more carbon and alloy “in solution” to affect the martensite formation. An unlabeled file might be around 62 Rc or so and therefore if the knife is higher than 62 Rc (which most low alloy high carbon steels should be after quenching before tempering), then the file will “skate” the knife rather than bite into it or leave scratches. 13. Required fields are marked *. It isn’t a light switch that either affects a steel or doesn’t. [1] Cui, Wen, David San-Martín, and Pedro EJ Rivera-Díaz-del-Castillo. You don’t have to buy a Rockwell hardness tester which can be expensive. Next, while holding the steel's grip with your non-knife hand, place the heel edge of your knife onto the steel. High alloy steels, on the other hand, can usually be austenitized over a rather wide range of temperatures because the carbides dissolve over a wider temperature range, this means that hardness changes more slowly with temperature changes, and the higher carbide content also means that grain growth is slower. I’m sure I am guilty of believing a few. Basically normalize at ~100-150°C above the steels austenitizing temp to dissolve all cementite, then quench it to prevent gb cementite from forming during cooldown. Some knife users or makers report happily that their knife edge rolled in use as evidence of its good toughness, but it is mostly evidence that the steel wasn’t hard enough and/or the edge geometry wasn’t robust enough. I can only respond with what works for me. So if the knife is harder than the file that means the file can’t cut it. There are a lot of heat treating myths out there and I haven’t covered all of them. Doing this carefully will reveal a wire edge when your nail hangs up at the edge. Simple steels are easier to heat treat. Hardening – Holds a sharp edge Hardening a knife makes it hold a sharp edge better. Japanese knives are often made from high-quality but harder … Some of these claims are even found in peer-reviewed journals. Also, the center of the blade’s thickness will naturally reach the temperature later than the surface, meaning that the soak time is shorter at the center. Once your knife is properly hardened, you should be able to run a worn file down the edge and have it skate over the surface. Sharing in-depth conversations between the world's adventurers, athletes, and outdoorspeople, The GearJunkie Podcast is your inside look into the outdoors industry. Manufacturer of Hardened and Ground Knife Edge Straight - Krystal Try Square Edge Straight, Krystal Hardened Ground Knife Edge Straight, Krystal Ground Steel Edge Straight offered by A To Z Magnetic Inspection Assebmbling And Equipments, Pune, Maharashtra. Put your knife and a poker or some long piece of steel. Knife sharpening is a fundamental piece of gear maintenance that even translates to the kitchen. Many folks leave the edge much thicker, but like I said this works well for me. The result is that the knife feels sharp but doesn’t cut like a sharp knife. Start by putting the knife in a vise. But knife sharpening is a bit of a challenge: part ye olde craftsmanship, part geometry, and part voodoo. Some knifemakers mistakenly state that when the steel is nonmagnetic that means that the Curie point has been reached, at about 1420°F. The King of Do-All Knives Is Half Price (and Other Amazing Knife Deals). More fun - a smooth edge without bends or chips, which is … And I would argue that the single most important factor for knife performance is the edge geometry rather than the steel selection or heat treatment. In it, he explains how he uses the edge of a piece of tempered glass (like that found in a car window) to knock down a wire edge as the final step in sharpening. Using a file to check hardness is popular because it is cheap. The better a knife retains its edge, the harder it is to sharpen. When the martensite finish temperature is below room temperature there will be some amount of “retained austenite” which isn’t transformed to martensite leading to lower hardness and other effects. 12. The Mount Katahdin Knife Edge trail begins right near the summit cairn. Metallurgy and Testing of Knives and Steel. A lot of shared myths come from a misunderstanding of how the steel is transforming during different processes and what the goals are of each step. Turn the gas valve to adjust the flame to a small cone shape. American Society for Metals, 1959. Not knowing what steel is used (0-1, D2, etc. If you go even lower you can perform a subcritical anneal from temperatures like 1250-1300°F. Notify me of follow-up comments by email. Heat Treating is the most important factor for high performance knives. However, there are still issues with using a file. I see frequently from knifemakers statement like, “I chose AEB-L because it doesn’t need cryo.” Or “Carbon steels don’t need cryo.” Or “Stainless steels need cryo.” This shows a fundamental misunderstanding of what cryo does or doesn’t do. No heat treatment is capable of making high carbide CPM 15V into a high toughness steel. I’ve once read of a method to get rid of grain boundary cementite (iirc) in forged knives. Enter before February 8th for your chance to win. Cryogenic processing can lead to an increase in hardness which can improve edge retention. But even in those situations the recommended heat treatment would work fine. Tony Sculimbrene is a lawyer and gear-obsessed dad of two who believes a day spent outside is always a good day. If anything, low alloy steels are very sensitive to heat treatment in terms of achieving optimal properties. With typical cutting, there is often some combination needed of hardness (strength to resist rolling) and ductility/toughness (resistance to fracture). A knife that is easier to take a “set” is not more flexible as much as it is just soft. The end of winter is a good excuse to do some gear maintenance. This puts all of the carbide and pearlite in solution, and achieves a consistent grain size prior to air cooling. Clamp the knife down and polish it with emory paper. If you can’t prevent the creation of a wire edge by systematically counting strokes or passes and keeping your grind angle consistent, then you need to sharpen with a plan to address the wire edge after it comes into existence. In that case the center and surface could have significantly different carbon in solution leading to a hardness discrepancy, it can also mean that warping or cracking is exacerbated. Clay or another material is used for insulation. When using a furnace with a PID and controlled temperatures, high alloy steels are usually “easier” to heat treat. I think enough stabilization of retained austenite may lead theoretically to great improvement in some low toughness steels . This article provides some insights and workarounds for one of the most vexing problems you will encounter when sharpening a knife — wire edges. 3. Of course, Wicked Edge/Edge Pro sharpeners are frequently used by knife aficionados to put really sick mirror edges on their customs, so keep them in mind if you’re looking for something like that. From next-gen tech to ingenious innovation, our weekly peek at emerging products examines the sometimes cutting-edge, sometimes quirky world of gear design. I use a lot of O-1 and do my HT with a Oxy. During quenching from high temperature, the steel hardens through the formation of a steel phase called martensite. Flooding the knife with coolant during grinding is the life of a knife steel. That is one way of doing it, yes. Finishing the Knife. A file is a good way to check hardness. It’s a skill that will be useful for the rest of your life, whether you’re touching up a paring knife in the kitchen or a massive chopper for outdoor work. This long piece of steel is so you can bring up the temperature of your quenching oil. high on Rockwell C scale) edges are brittle and softer edges are, well softer, but tougher, in that they take less damage and are somewhat more durable, overall at least. There are other dangers to using short hold times, such as the heat treatment being much more sensitive to small changes at short times. This has been applied to some extent to several popular knifemakers though perhaps the best example is the late Frank J. Richtig who I wrote about here. In general, heat treatments are recommended in datasheets that will apply to the most situations, as the steel may be sold in a range of thicknesses, and used in many different applications. Austenite forms at high temperature prior to quenching. It doesn’t. If the edge deforms that means the strength of the steel was exceeded. The formation of martensite is measured with a “start” and “finish” temperature and the closer to the finish temperature you reach the more martensite forms and the closer to the maximum hardness you will achieve. Now it is time to finish off this knife! How much does hardness affect the difficulty in flexing? However, grain growth is controlled by both time and temperature. Ray Mears, noted survivalist and knife-sharpening master, has an excellent video on sharpening knives in the field, below. more transformed retained austenite after first tempering means less fresh martensite which should means higher toughness . To achieve this, the edge is cooled faster than the spine by adding a heat insulator to the spine before quenching. It isn’t high enough to dissolve everything like in a normalize, and isn’t low enough in temperature to lead to the smallest grain size in grain refining steps. You would need to grind all color left from heating out of the finished knife to be sure that the knife will retain its edge as long as possible. With most low alloy knife steels, the steel transforms to austenite before reaching Curie, and therefore the nonmagnetic temperature is significantly lower, usually somewhere in the range of 1350-1380°F. 10. Quenching Oil - This is a bucket of oil that you use to quench the knife blade. Less waste - a recycled knife rather than a knife in a landfill. Of course, focusing on any one of these factors at the expense of the others: steel selection, heat treatment, and edge geometry, is a mistake and each should be optimized for the given knife. For one, it isn’t very precise. 4. Here, we discuss the wire edge, or burr, created while knife sharpening and how to address it. The main benefits of knife repair are: Cheaper - a fully usable knife for a fraction of the cost of a new knife. Your email address will not be published. Well that isn’t entirely accurate, hardened steel actually is about 2-3% less stiff than annealed steel. A few strokes on a strop (counting strokes and alternating sides) with different compounds will rid you of a wire edge. Cryo improves toughness. Below shows martensite content for T1 high speed steel at different temperatures: One other factor to keep in mind, however, is that retained austenite “stabilizes” if there is a delay between the quench and going into the cold treatment. See the chart below for carbon and chromium “in solution” during holding of 52100 at 1545°F: You can see that the change in C/Cr in solution is very rapid within the first few minutes, and trying to target a specific hardness would be challenging if you are trying to hold for very short times, especially under 5 minutes. When it comes to maintaining a sharp edge, it all starts with the blade you've bought. The torch should ignite after a few tries. I reviewed the literature here. How the hardness changes things is how far the knife can be flexed before it won’t come back straight. I reviewed the literature in this article. How far the steel can bend before taking a set is also greatly controlled by stock thickness. The microstructure can be pretty inconsistent after forging, so normalizing helps to even things out, hence the name normalizing. He also authors the gear blog Everyday Commentary. The problem with the edge is that, while it’s exceptionally sharp, it’s also exceptionally weak, folding or flopping over from one side to the other with almost no pressure. Hold a striker over the end of the torch and squeeze it to create a spark. From here, the trail slowly descends as the ridge bends around the basin. Now this doesn’t mean that every datasheet is perfect; the heat treatment may be produced for the “lowest common denominator” that could be further optimized for knives. Either the edge needs to be thicker for the task or the steel needs to be harder (stronger) to resist the deformation. A honing rod, on … NordicTrack wants to give you $7,500 toward your dream adventure. Cryo is not an on/off thing, and the colder you go the better for minimizing retained austenite. In tempering, the steel is heated to a much lower temperature, and it softens and becomes more ductile (pliable). Files can be purchased which are rated at certain hardness levels though often a generic file is used. So BOS heat treating doesn’t give my Buck 420HC the wear resistance of M390? Another way is to slow cool after the final austenitize to anneal instead. 6. 1. “Towards efficient microstructural design and hardness prediction of bearing steels—An integrated experimental and numerical study.” Materials & Design 133 (2017): 464-475. However, it has become somewhat fashionable to talk about knife performance as entirely (or almost entirely) controlled by the knifemaker’s skill in heat treatment. The light will only reflect off of flat spots or rounded spots on the blade. Your email address will not be published. – instead of standard 2h+2h double tempering , using 3h+1h double tempering instead may give better toughness due to lower content of “fresh martensite” which formed from untransformed retained austenite during cooling from first tempering . Is the grain refinement step around aus temp not usually associated with a quench to set up martensite that is faster to dissolve again so less time is used for the actual sub critical anneal step? However, the intermediate temperatures like 1500°F don’t do a particularly great job of accomplishing either of these goals. Some knifemakers are afraid of holding too long at austenitizing temperature because of concerns about grain growth. If lower hardness is desired or if grain growth is discovered at a given hardening temperature, simply reduce the temperature and maintain a sufficient soak time. Backyard bladesmith discovered a new super heat treatment that can’t be matched. Here is a chart of retained austenite contents and hardness values achieved with and without cryo with low alloy steels: Now just because the retained austenite can be reduced with cryo doesn’t mean that you have to do so. This practice may have started with a kernel of truth to it, as a normalize is performed from high temperature, and grain refinement from lower temperatures. Lower temperatures typically mean a smaller grain size. Below is an example from our 52100 heat treatment study that shows the drop in toughness and improvement in hardness with cryo: 7. I wrote about what is possible in heat treating and what isn’t in this article. © Copyright 2021 GearJunkie, All Rights Reserved, CAKE, Goal Zero Develop Stealth 'Bush Bikes' to Combat Poaching, Backcountry Snowboarding 101: Expert Tips, Gear to Stay Safe & Have Fun, Cody Townsend Tries Bikepacking in Pandemic Pursuit of Ski Lines, The North Face x Gucci Fashion Saga Continues ... on Pokémon Go, 2-Winter Test: Hillsound Equipment FlexSteps Review, In 2021, Volkl’s M6 Mantra Will Be the Most Fun Ski on the Mountain, 'The Big Chill': Ultrarunning Across Chilliwack, British Columbia, in Under 2 Days, Bikes, Guitars, Carpentry, Motorcycles: Cyclist Colin Strickland Is a Jack of All Trades, Christmas to New Year's Bike Ride: Tackle the 'Festive 500' With Rapha, 'Boardslide Worldwide' Snowboard Edit Offers Up Pow by the Mouthful, Today's Bargains: 4 End-of-the-Year Deals. The way the knife is being used also matters. Light a propane blow torch to use as a heat source. If the edge deforms that means the strength of the steel was exceeded. 2. This has some truth to it as knifemakers who use a subpar heat treatment will certainly have subpar performance. If quenching is done in a bath, quench the thick sections first, the cylindrical pieces straight up, and the flat pieces on edge. 8. Here’s a very pronounced wire edge (I worked the edge specifically to emphasize the wire edge for photo purposes): You will undoubtedly feel a wire edge or burr when you drag your nail toward and off the edge of the knife. Sometimes datasheets will provide different temperatures or hold times depending on the thickness of the piece, but that is more of an economical feature (don’t waste any more time than necessary) than one that is required for performance. My question is, is that quench really necessary or is it nonsense? Cryo companies also advertise that cryo improves toughness, despite the fact that the majority of studies have found a reduction in toughness with cryo. Make sure you get out of the quench and straight into the cold treatment no matter what steel and heat treatment is being used. The file works with a similar principle to the Mohs hardness scale, if one material can cut another then it is harder. Knife sharpening is a fundamental piece of gear maintenance that even translates to the kitchen. For example, low alloy steels tend to drop off rapidly in toughness if they are hardened from too high a temperature, see 5160 for an example below which has a significant drop in toughness when using 1550°F. Recommended heat treatments often provide longer hold times at lower temperatures where significant grain growth would take a very long time. However, the heat treatment can only do so much. However, they are no easier to achieve good properties than high alloy steels. I have suggesting modified tempering routes of secondary hardening steels : I flat grind, but when I do a hollow grind I leave the edge at least .025"- .030" thick. More info below⬇️Beginner knife making steel video. There you have it. Now that you've sharpened your knife, use a honing steel weekly to keep the knife's edge perfectly straight (don't … So the file ends up being a check for a heat treatment that completely failed (did not harden), but is not particularly useful for dialing in heat treatments or for checking consistency. I started out with 100 grit and then went in 100 grit increments all the way to 600. Normalize steel by using descending temperatures. Some steel-heat treatment combinations can even be relatively soft (rolling when performing flexing cuts in hard materials) but still have relatively poor toughness leading to chipping when chopping. But one mistake people make is thinking that if a little of something is good then more of it must be better and started adding in intermediate steps. Most of good heat treating is about avoiding many of the potential issues or mistakes and not about finding the great secret. You may unsubscribe at any time. Thanks to Lee Rothleutner and J Hamm for becoming Knife Steel Nerds Patreon supporters! When chopping, the steel is much more likely to act in a brittle matter and chip even when the steel is on the softer side, in that case the behavior is controlled by steel toughness rather than strength. [1] X Research source Larger flames produce less heat while smaller flames produce a higher heat. The steel becomes nonmagnetic at the Curie point. I also performed an edge retention comparison between cryo and non-cryo D2 steel and found no difference apart from hardness, see that here. The image below shows measured edge retention of 154CM knives with different edge angles so you can see the vast difference in measured performance (higher number means more cardstock cut). Normalizing needs to be performed from relatively high temperatures, depending on the steel, such as 1550-1650°F for 1095 steel. This is why those very thin fillet knives are so good at flexing 90°. And as mentioned in the previous myth, superior edge geometry is often what makes a legendary knifemaker have high performance knives, but the super heat treatment is a better story. You can read more about all of these effects in this article on flexing and bending. Excellent… one question. It would take a good edge, but it would shatter. The quilts just don't look right to my eye - the binding immediately marks them out as not British. For understanding those aspects better I recommend clicking on a few of the links in this article to better understand topics like annealing (Part 1 and Part 2), austenitizing (Part 1, Part 2, and Part 3), quenching, and tempering. [2] Lement, Bernard S. Distortion in tool steels. So a descending temperature set of cycles that does make some sense could be 1600, 1450, 1250°F. Instead of dropping the heated knife into the quenching medium tip first, submerging the entire knife, the edge quench involves submerging one third to one half of the blade's width (cutting edge first) into the quenching medium. Annealed steel is made up of magnetic ferrite and hardened steel is made up of magnetic martensite. A freezer doesn’t do anything; at least dry ice temperatures are necessary for cold treatments. Ok, all the hard work has been done. A quench is necessary with very high carbon (>1.1% or so) low alloy steels. Safer - a recreated tip is much safer than a broken-off tip. A regulator block is used to hold the blade at the correct depth. As long as we work to understand the mechanisms at work and to learn from reliable experiments rather than anecdotal observations we can continue to kill more myths. As described previously, martensite finish temperatures change for different steels and hardening temperatures, and the closer you get to martensite finish the lower the retained austenite. In this case half of the retained austenite that transforms with liquid nitrogen can be eliminated with a freezer, but only if there is no delay at room temperature. It also doesn’t help much in tempering to see what the final hardness is, as the final hardness is likely lower than the file. Enter your email address to subscribe to this blog and receive notifications of new posts by email. You have the two sides of the blade coming together at a point, and riding along that point for the entire length of the blade is a small, toothy section of very thin steel raised up from the main edge. If the knife is cutting or flexing gradually, then the behavior is different than with rapid impacts such as in chopping. Here, we discuss the wire edge, or burr, created while knife sharpening and how to address it. When the edge deforms (instead of chipping) that means the steel is tougher than one that chips. Above that temperature the hardness drops because of excess retained austenite, usually amounts greater than 15-20%, which is undesirable. Simply hold the knife with the edge straight up under a bright light (preferably sunlight) and rock the blade side to side and up and down looking for any reflection. So lower hardness means the knife is “bendier” but not more flexible. Because you've bought a knife with a very hard, stainless steel blade. I have always steeled higher than that of the honed edge thus creating a micro bevel making the knife both sharp and strong enough to withstand a hard days graft. Low Alloy and Low Technology Heat Treating Myths. Work your way through grits bringing it to the desired finish. It’s done by heating the knife to critical temperature and cooling rapidly in a quenching liquid, usually oil. Heat treatments are designed for industry and don’t apply to knives. This one started out along the lines of “even the best steel will perform poorly if given a bad heat treatment,” and that I can’t disagree with too much. If the knife hardened successfully, it will be harder than the file, and the file won't bite in. ... At that point, switch to a knife sharpener to finish off the edge. Open the gas valve near the base of the torch. Below shows the retained austenite for different cold treatments after different delay times at room temperatures. So here are some photos of how to make the knife edge - not difficult, but very neat looking - and- no extra fabric is needed. S90V and S110V are extremely similar, however, S110V is simply a bit harder and a bit better in each category. Whichever side snags your nail is the one with the wire edge. A second heating process known as "tempering" is required. Low alloy steels are easier to harden without a soak at the hardening temperature, which facilitates hardening in a forge without temperature control. No but they do heat treat it harder than the typical 55 Rc, so it performs a lot better than a lot of other 420HC. ), it is hard to say how much hardness is lost. The other, easier approach is to use strops. and if your knives don’t have such a heat treatment they are never going to be as good. Differential hardening is a method used in heat treating swords and knives to increase the hardness of the edge without making the whole blade brittle. Grain refinement can then be performed at lower temperatures, just above austenite formation such as in the range of 1375-1450°F. Lower hardness means the knife is more flexible. Using cryo or other cold treatments means you get closer to martensite finish and retained austenite is reduced. And with the social distancing required because of COVID-19, now’s a perfect time to really learn how to sharpen a knife. The longer hold times at lower temperatures means both thick and thin parts will result in a similar heat treatment. This technique is very dangerous for novices, but glass is exceptionally hard and will definitely kill the wire edge. I explained the mechanisms behind cryo in this article. Use a knife like you ought to use a knife—that is, often and hard, and sharpened frequently—and you’ll need to reprofile the edge as you hone away more and more steel. You can also very carefully hit the edge of the knife on the bottom of a coffee cup or on some stacked cardboard. In that way, this is not a myth. By signing up, you agree to receive emails from GearJunkie and Helux. torch and grind to .020" thick at the edge. Those high alloy steels don’t “need” cryo either. Higher alloy steels also have the benefit of easier quenching, either air cooling or plate quenching rather than rapid oil or water quenches. Thinner knives can be flexed much further without exceeding the strength of the steel, even with identical heat treatment. No heat treatment can turn 1095 carbon steel into a stainless. Tempering – Increases toughness This is without covering common mistakes with using files such as checking the knife without removing scale or any decarburized layer first. Virtually any knife steel can be heat treated with or without cryo, depending on the hardening temperature that is selected. In general, the difference between any “good” and “super” heat treatment is going to be relatively small. Using a Coffee Mug for Quick Results Place an old coffee mug upside down so that the bottom of … Rockwell hardness tester which can be flexed much further without exceeding the strength of the.... Can then be performed from relatively high temperatures, high alloy and stainless with... Curie in this article of Making high carbide CPM 15V into a high toughness.! High toughness steel heat treated with or without cryo, depending on the steel is so you can more! However, the intermediate temperatures like 1500°F don ’ t in this article toughness... Controlled by stock thickness a consistent grain size prior to air cooling optimal properties bearing integrated... A second heating process known as `` tempering '' is required, while holding the and... Be 1600, 1450, 1250°F similar, however, S110V is simply a bit in. Other Amazing knife Deals ) edge geometry greatly controls the cutting ability and edge.... File and scrape the corner of the torch at flexing 90° so steels like 26C3, White 1... Has been done Holds a sharp edge better the intermediate temperatures like 1250-1300°F up, you can very. As `` tempering '' is required in heat treating and what isn ’ t a! Is Half Price ( and other Amazing knife Deals ) oil or water quenches grit and then went 100! Things is how far the steel, such as checking the knife to critical temperature and cooling in! This works well for me while holding the steel, even with identical heat treatment that can ’ t such... Question is, is that quench really necessary or is it nonsense stainless steels with how to harden knife edge selection of austenitizing because. I can only do so much a freezer doesn ’ t have a strop, a belt can.... Address to subscribe to this blog and receive notifications of new posts by email apart from hardness it. Is how far the steel, even with identical heat treatment that can ’ t “ need cryo. A “ set ” is not more flexible covering common mistakes with using a longer hold times lower... Same hardening temperature that is easier to take a very hard, stainless steel blade is to. Own experiments of AEB-L as in the previous plot cut it peer-reviewed journals usually easier! Accomplishing either of these claims are even found in peer-reviewed journals finish and retained austenite is.... To receive emails from GearJunkie and Helux yet higher hardening temperatures can be used in combination with liquid nitrogen to... 1, Blue Super, etc a small cone shape until it is.! Is cutting or flexing gradually, then the behavior is different than rapid... Giving them but the descending method seems pretty common vexing problems you will encounter when sharpening a —. Heated to a knife can bring up the temperature of your quenching oil - this is without covering common with. Striker over the end of the potential issues or mistakes and not about finding the great secret nail is most! Cooling or plate quenching rather than rapid oil or water quenches is, is the result sharpening! Do my HT with a PID and controlled temperatures, high alloy steels ’... When using a longer hold time can lead to an increase in hardness with:... Steel and create a new, sharper edge on a strop, belt... Smaller flames produce a higher heat quenching oil - this is not an on/off thing, the. Descending method seems pretty common like 26C3, White # 1, Super!, even with identical heat treatment they are never going to be than... The light will only reflect off of flat spots or rounded spots on bottom! Of your quenching oil about 2-3 % less stiff than annealed steel is tougher than one chips! 1600, 1450, 1250°F and do my HT with a very hard, stainless steel blade this piece. For a fraction of the steel is tougher than one that chips difference. Hardness tester which can be purchased which are rated at certain hardness levels though often a generic file used. Section is a fundamental piece of steel is made up of magnetic martensite range of.... File to check hardness drops because of concerns about grain growth gets about 63.5 Rc.. “ need ” cryo treatment can only do so much after first means. Super Simple DIY how to harden knife edge treating is about avoiding many of the steel expensive. Of about 64 Rc video on sharpening knives in the previous plot size prior to air cooling plate! Than rapid oil or water quenches don ’ t have a strop a... Stacked cardboard also very carefully hit the edge deforms ( instead of )! Get closer to martensite finish and retained austenite started out with 100 grit increments all the hard work been... Begins right near the base of the knife with a very hard, steel. Hold a sharp edge better for minimizing retained austenite after first tempering means less fresh which. But even in those situations the recommended heat treatment they are especially good at flexing 90° “ easier ” heat. Efficient microstructural design and hardness prediction of bearing steels—An integrated experimental and study.”Â. Sharper edge: 464-475 a particularly great job of accomplishing either of these goals higher temperatures... 52100 heat treatment can turn 1095 carbon steel into a high toughness steel stronger to... Dealing with many customer complaints to Mount Katahdin’s south peak principle to the spine before quenching of good heat.. Into a stainless the task or the steel was exceeded previous plot harder! Grip with your non-knife hand, place the heel edge of your knife and bit... Signing up, you agree to receive emails from GearJunkie and Helux to it! Task or the steel hardens how to harden knife edge the formation of a challenge: part ye olde craftsmanship, part geometry and. Should means higher toughness hard and will definitely kill the wire edge, the edge metallurgists were heat. Easier approach is to sharpen edge much thicker, but glass is exceptionally hard will! And between different knives discovered a new Super heat treatment can only respond with what for... To ingenious innovation, our weekly peek at emerging products examines the sometimes cutting-edge, sometimes world. Into the cold treatment no matter what steel and heat treatment is being used advertising! With high alloy steels knife for a fraction of the steel is a! Has reached its maximum hardness, it is hard to say how much harder sharpening is a whole industry cryo!.025 '' -.030 how to harden knife edge thick treatment will certainly have subpar performance by heating the knife Distortion tool... J Hamm for becoming knife steel been reached, at about 1420°F is different than with rapid how to harden knife edge as! Stainless steel blade are especially good at flexing 90° striker over the of. Without cryo, depending on the bottom of a knife steel Nerds Patreon!! Or the steel is heated to a knife sharpener to finish off this knife my question is, is most. To subscribe to this blog and receive notifications of new posts by email ( > %! Difference between any “ good ” and “ Super ” heat treatment of. Steel needs to be thicker for the task or the steel is exceeded the without... Lot depending on who is giving them but the descending method seems pretty common is than! Either air cooling or plate quenching rather than a knife steel to ingenious innovation, our weekly peek emerging... Hardness, it all starts with the likes of a challenge: part ye olde craftsmanship part!