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MagnaMax Is Here: The Next Evolution in Knife Steel

By: Larrin
19 January 2026 at 17:15

Background

MagnaMax has been in development for a long time. When I first proposed the idea for MagnaCut to Crucible and Niagara in June 2019 I also proposed a high wear resistance version I was calling “stainless 10V.” This version was intended to match the combination of toughness and wear resistance in the non-stainless grades K390, Vanadis 8, and CPM-10V. K390 has developed some popularity in recent years from Spyderco using it in many knives. This steel hits a real sweet spot for having good toughness with very high wear resistance. That high wear resistance gives it excellent edge retention. MagnaMax achieves that same level of toughness and edge retention but with the same excellent corrosion resistance of MagnaCut. MagnaMax achieves these properties by using the same general approach to composition as MagnaCut while increasing carbon, niobium, and vanadium for wear resistance. We are still waiting for the ok from our patent lawyer before releasing the composition, but that will hopefully come soon. The first commercial “heat” of MagnaMax has been delivered to a few knife companies, so it is time to talk about the steel, even if we can’t reveal every detail yet.

With MagnaCut I tried to preach the benefits of “balance” for properties. Not going too extreme for any one property. I promoted the benefits of thinner edges using its excellent toughness, while still having very good wear resistance and edge retention. However, I knew that for some knives they would still benefit from higher edge retention, and that many knife enthusiasts would want a higher edge retention version of MagnaCut. So here it is. I tried to increase the edge retention by a large margin while still maintaining the goal of good balance, and I think the new steel is very successful at achieving that.

Video

There is a video version of the following information:

Edge Retention

The biggest change from MagnaCut is of course the increase in edge retention. MagnaMax matches the edge retention of K390 and Vanadis 8, as was intended:

This also puts it in the same range as steels like CPM-10V and CPM-S110V. It puts it above several notable steels like M390, ZDP-189, S60V, S30V, and CPM-M4. This is a sizeable increase in edge retention over MagnaCut.

Toughness

My stainless toughness chart has gotten pretty busy. MagnaMax is just above Vanax, S35VN, CPM-154, and XHP. These four steels were the toughest powder metallurgy stainless steels available prior to MagnaCut. So MagnaMax matching or exceeding the toughness of these grades is exciting. You will notice that MagnaCut is on the chart twice, once as “MagnaCut” and once as “Erasteel MagnaCut.” You can read about the switch to Erasteel for MagnaCut in this article.

Comparing against its benchmark grades, MagnaMax is the same as Vanadis 8 and K390, a small step above CPM-10V. So even though it is a stainless it still matched the toughness of the non-stainless powder metallurgy steels. So those that have been happy with the toughness of their K390 knives will also be happy with MagnaMax.

Edge Retention-Toughness Balance

Comparing the edge retention and toughness at the same time, MagnaMax also looks excellent on the chart:

With similar edge retention to S110V but substantially higher toughness, the property balance is much better than previous stainless PM steels. This datapoint is for 62 Rc, it could be a bit higher for edge retention at the cost of some toughness at higher hardness. You will notice that in the past, if you wanted higher edge retention than MagnaCut or S35VN, there was a steep drop off in toughness, and the toughness was relatively flat with higher levels of edge retention from there. MagnaMax has similar toughness to S35VN but with much greater edge retention, also highlighting its well-balanced properties. Comparing with the popular M390, MagnaMax is a significant improvement in both toughness and edge retention. Previously this combination of toughness and edge retention was only available in non-stainless powder metallurgy steels.

Microstructure

MagnaMax gets those excellent properties by achieving a very fine carbide structure made up of hard vanadium and niobium carbides. It has a similar amount of carbide to K390, with a somewhat finer carbide size:

MagnaMax

K390

MagnaMax has about 16% carbide volume, which is roughly double MagnaCut. This is why MagnaMax has so much greater wear resistance and slicing edge retention:

MagnaCut

MagnaMax has so much greater toughness than previous high edge retention stainless PM steels because its carbide volume is much lower and the carbides are much smaller. Chromium carbides are relatively large in powder metallurgy steels, so eliminating them from the microstructure gives much better toughness. Notice how big the carbides are in M390:

M390

S90V

S110V

Corrosion Resistance

One of the things that made MagnaCut popular was that its corrosion resistance was surprisingly excellent, better than most other stainless knife steels. I compared its corrosion resistance to other high edge retention stainless steels with my standard 1% saltwater test:

M390 and S110V actually have pretty good corrosion resistance, I had previously given both a “9” in my knife steel ratings. So it isn’t surprising that both of those grades had only a few small rust spots in this test. S90V has worse corrosion resistance and had significant rusting. MagnaMax, however, showed no rust spots in this test.

The Long, Long Development

MagnaMax has been a long time coming. As I said in the intro section, I first proposed it in 2019. We made the first heat with Crucible Steel in 2023. Crucible made a second heat right before their bankruptcy. The first heat was used by a few knifemakers and knife companies but did not have a name yet. So the companies called it different things like MagnaX, ProjectX, etc. That second heat did not provide as much information for dialing in the composition as I had hoped as they overshot the carbon target but a sizeable margin. This heat was primarily sold to Spyderco for their mule series of knives. These knives are a good representation of the steel’s properties, though the high carbon means that the corrosion resistance is lower for that prototype steel than the final versions. It’s still very good corrosion resistance, but not as good as it could have been. Once we have more representations of the final material for testing I will be doing further work like developing final datasheets and ensuring that all of the element targets yield consistent properties even when they are on the lower end or upper end of their allowable ranges. There are a lot more heat treatment combinations I need to test to optimize recommendations so that the material has its best possible combinations of hardness, edge retention, toughness, and corrosion resistance.

Wide Release Date

As I explained above, it is a bit difficult to say what the release date of MagnaMax is/was. In some ways it has already been released. However, the steel has not been given a final, wide release when it can be regularly purchased. There are many pounds of MagnaMax ingots being delivered over the next few months, from our dual powder steel suppliers of Erasteel and Carpenter. The official release date will be some time in Q2 of this year (2026).

Summary

MagnaMax maintains the excellent corrosion resistance and hardness of MagnaCut, while significantly improving its wear resistance and edge retention. This means it took a small cut in toughness, of course. MagnaMax matches the toughness-edge retention balance of K390, which has been popular in Spyderco folders recently. I think this is a sweet spot for performance for a wide range of knives that benefit from high edge retention. I’m excited to see what kinds of knives MagnaMax ends up in.

The post MagnaMax Is Here: The Next Evolution in Knife Steel appeared first on Knife Steel Nerds.

Testing Erasteel MagnaCut (vs Crucible Original)

By: Larrin
12 January 2026 at 15:07

Crucible, Niagara, Erasteel, and MagnaCut

In case you haven’t been following steel news, Crucible Steel went through a bankruptcy and no longer exists. I interviewed Bob Shabala of Niagara Specialty Metals about this transition several months ago. Niagara is the company that purchased ingots from Crucible and would hot roll, anneal, and distribute them to knife companies and steel suppliers. They have also recently started a new online store to better sell directly to individual knifemakers. Niagara has managed to keep production going for a wide range of Crucible (and other) knife steels, including:

MagnaCut, CPM154, S30V, S35VN, S45VN, S90V, 3V, 4V, CruWear (NSM Wear), 154CM, 20CV, M4, CPM D2, D2, 440C ESR, 416SS, 6-4 Titanium. MagnaMax should be available in early 2026.

Erasteel purchased the rights to Crucible Steel trademarks. Erasteel is headquartered in France, but its powder metallurgy production is in Sweden. Niagara worked with Erasteel to retain the exclusive rights to purchase MagnaCut ingots and sell the steel to knifemakers and knife companies. Erasteel produces very high-quality powder metallurgy steel. Bob Skibitski was the head of the powder metallurgy steel production at Crucible Steel for 20 years and was hired by Erasteel. He reports that Erasteel production yields higher-quality, “cleaner” steel. You can read his thoughts in an article on Niagara’s website.

Video

There is a video version of this article:

Previous Testing of European Powder Metallurgy Steels

I have published two studies before comparing manufacturing from different powder metallurgy companies. One compared M390, 20CV, and 204P (with the somewhat different Elmax thrown in). The other compared Z-Wear (same as CPM-CruWear) between Crucible and European production. With the M390/20CV/204P study I found the biggest difference between manufacturers was the oxygen content. Oxygen is an impurity and it leads to oxide inclusions that are detrimental to properties. This is something advertised by companies like Bohler-Uddeholm, that their process is “cleaner” and leads to fewer oxides. However, the toughness of the grades was identical, perhaps in part because the carbide content is quite high and carbide size of M390/20CV/204P are basically the same. Even though Bohler advertises a finer powder size, the carbide size is mostly a result of carbide “coarsening” during high-temperature processing after the powder is made, rather than differences in powder size.

M390

20CV

So the carbide volume, carbide size, and resulting toughness are primarily controlled by the composition and method of manufacture (powder metallurgy) rather than the quality of the production. If the oxides are smaller and in a lower volume than the carbides, then the limiting factor for toughness is the carbide, and so oxide inclusion content doesn’t much come into play.

In the Z-Wear study I thought there might be more of an effect of oxide inclusions than the M390 because it has significantly lower amount of carbide. However, the two steels tested relatively similarly in terms of toughness:

In this case the European-produced version of Z-Wear had slightly higher toughness but it was also at a lower hardness, giving it a slightly worse hardness-toughness balance. In general I called them equivalent in the article. I actually suspect that Zapp had accidentally mixed up the labels of the steels because the oxygen content was lower in the steel that was labeled as “USA” once it was delivered to me. That would mean the European steel had a slightly better hardness-toughness balance, rather than the USA Crucible version.

USA vs European Z-Wear that might have been mislabeled before they were sent to me

Dialing in the Composition for Erasteel MagnaCut

With switching over to Erasteel for MagnaCut production we had several things we needed to figure out. One that might be surprising to people is that steel composition testing is highly dependent on calibration of the instrument and which technique is used. For example, there were significant differences in composition measured between grades in the M390/20CV/204P study and the Z-Wear study. This is not always clear because there is some distribution of composition in manufacturing. If the target is 10% chromium, there is some acceptable range by the manufacturer like 9.5-10.5% Cr. So you can’t measure just one example from different manufacturers and know what the offsets are. So we took pieces of MagnaCut from multiple Crucible “heats” and sent them to Erasteel so that they could have appropriate offsets to match the Crucible material. We will continue to monitor the performance of the new MagnaCut material because of the distributions. If heats on the low end or high end of certain elements are not performing well in one performance category or another we could shift the target or tighten the acceptable ranges. This is the side of development and quality control that is often not seen by the end customer and is probably not very exciting.

Erasteel vs Crucible MagnaCut

One very important part of MagnaCut is its high corrosion resistance. So I tested with my standard 1% saltwater spray test. Most stainless knife steels will see some rust spots with this test. In this case neither the Crucible or Erasteel material showed any rust spots:

I also tested the hardening response. For a given heat treatment the hardness was very similar, perhaps the Erasteel material was slightly higher:

Surprisingly (based on the Z-Wear and M390 results), the toughness of Erasteel MagnaCut was significantly higher:

You can see that the Erasteel MagnaCut was significantly higher, matching AEB-L at ~62 Rc, and exceeding it at ~64 Rc. I wouldn’t necessarily extrapolate that up to AEB-L levels at 60-61 Rc but in that hardness range it was very good. Comparing with non-stainless steels this also makes Erasteel MagnaCut look more competitive:

While Crucible MagnaCut was a bit below the best results of CPM-CruWear and Z-Wear, the Erasteel version matches or exceeds it. In my knife steel ratings I had given MagnaCut a “7” for toughness and CPM-CruWear an “8,” so this is exciting. MagnaCut has a similar carbide volume to CPM-CruWear but has even smaller carbides so it was always a bit disappointing that the measured toughness wasn’t matching it. Perhaps this was a case where oxide inclusions were reducing toughness slightly in the Crucible version. Erasteel MagnaCut even roughly matched the new Bohler K888 steel, advertised for its high toughness, and tested better than steels like Vanadis 4 Extra. One thing to note is that toughness differences are basically on a “log scale,” meaning that differences at small values are bigger than those at large values. So the difference between 5 and 10 ft-lbs is about the same as between 10 and 20 ft-lbs.

One difference I noted in toughness testing is that using an austenitizing temperature of 2150°F (1175°C) and then tempering to desired hardness led to better toughness than lower austenitizing temperatures. With Crucible MagnaCut the optimum property balance was with 2050°F (1120°C).

You can see that for a constant toughness of ~20 ft-lbs that the hardness can be higher for that same toughness with a higher austenitizing temperature, about a 2.5 Rc increase.

Summary and Conclusions

The MagnaCut now being produced by Erasteel matches or exceeds the properties of the previous Crucible version. Specifically the toughness showed an improvement. We will continue to monitor the properties of the new material to ensure the performance meets expectations with the new manufacturing partner.

The post Testing Erasteel MagnaCut (vs Crucible Original) appeared first on Knife Steel Nerds.

Pop’s ProCut – A New Carbon Steel for Knives

By: Larrin
4 June 2025 at 22:38

My steel research is supported through Patreon. Patreon supporters saw the news on Pop’s ProCut before anyone else. There is currently an article about the upcoming MagnaMax only available on Patreon.

Video

Here is a video version of the following information:

Development

In March 2024 Joey Berry of Pop’s Knife Supply called me and said he wanted to develop a new steel. He said that their most popular steel was 80CrV2 and so he wanted to make “80CrV3.” “You mean 80CrV2 but with a little more vanadium?” He said no but some kind of “sequel” to 80CrV2 that would be more exciting. I told him that doesn’t give me much to go off of but I would think about whether I had any good ideas along those lines. I thought about gaps in the market in the area of low alloy knife steels (“Carbon steel”) that would also be usable by the knifemaker that is buying 80CrV2. It occurred to me that our selection of high nickel steels is very limited; 15N20, L6, and 8670 are pretty much it. These steels are high in toughness and offer good hardness to go with it, but have no real wear resistance to speak of. 80CrV2 is in a similar position just without the nickel. I thought if we added some tungsten and vanadium to a high nickel steel we could make the steel more balanced; give it some wear resistance along with the high toughness. Those carbide pinning elements would mean that the steels are more beginner friendly for forge heat treating. 15N20, for example, already sees grain growth around 1500°F (815°C) and so its toughness drops very rapidly even when only slightly overheated. If the tungsten and vanadium were kept in check the forgeability, grindability, and polishability would remain high. This would also offer an alternative to other tungsten/vanadium steels like Blue #1, V-Toku2, Wolfram Special, 1.2519, and others. Those steels don’t have much toughness to speak of, so we could combine the best of the nickel steels with the best of the tungsten/vanadium steels. Another exciting element with the high nickel is the possibility to use the steel in pattern-welded Damascus as a “bright” layer. This gives an option for a higher wear resistance steel with better edge retention for that component of the Damascus. I told Joey about my idea and we decided to move forward with it.

We took the composition I came up with to a steel mill in Europe and they agreed to make it. I spent a bunch of time working on optimal annealing for the somewhat similar 15N20 based on the limitations of their production annealing process. Based on that we generated an annealing procedure to make the steel respond well to forge heat treating.

Composition and Tungsten/Vanadium Carbides

Here is the composition of Pop’s ProCut compared with other grades in its category. The far right column says “MC (%)” which is a calculation of how much total vanadium and tungsten carbide each steel contains after heat treating. One thing you will notice is that since tungsten is a heavy element it does not contribute as much to the MC as you might expect. For example, CruForgeV with 0.75% vanadium has more MC than Wolfram Special which has ~2.25% tungsten. ProCut uses a combination of vanadium and tungsten in a similar fashion to O7 and 1.2519 steels. So it has similar MC to steels like Blue #1, 1.2519/O7, and Wolfram Special, and more MC than Blue #2 and O1. The other nickel nickel steels (15N20, L6, and 8670) of course do not have any MC. These very hard carbides give the steel wear resistance.

Austenitizing, Tempering, and Hardness

A major goal for this grade was to be “easy” to heat treat with a forge. This requires a wide range of austenitizing temperature where full hardness is achieved while avoiding a toughness drop with higher temperatures. 80CrV2 steel varies a lot with starting microstructure, and two of the mills that make the steel lead to very different heat treating response:

So we wanted to avoid this issue that 80CrV2 sees. We did this by keeping the chromium low and also working with the manufacturer to dial in the annealing procedure so that carbides aren’t too coarse (making them difficult to dissolve). I also compared the austenitizing response with my recommended anneal (described later):

You can see that the hardness reaches its maximum around 1475°F and then does not change above that temperature. If using the anneal I recommend the microstructure is a bit finer and so this can be dropped even further to 1375°F. Thus for heat treating in a forge you can heat the steel to “a shade brighter” after reaching nonmagnetic and the steel will fully harden. If you forge and follow the recommending normalizing and annealing procedure you can even quench from nonmagnetic if you wish.

If the steel is austenitized in that range (1475°F or higher) the tempering is roughly the same regardless of the austenitizing temperature. Here are datapoints for both 1550°F and 1625°F:

You can see that the hardness is relatively high, still 64 Rc after tempering at 300°F, which is generally as low as I recommend for tempering most any steel. With a 450°F temper the steel is still above 60 Rc.

Toughness

Austenitizing

In our heat treating and toughness experiments we found three different regions of toughness behavior:

Below 1500°F, the steel shows an increase in toughness with increasing temperature. From 1500-1575°F the toughness is roughly flat. 1625°F and above shows a big jump in toughness where it is flat again up to at least 1675°F. The reason for this behavior we figured out by looking at the microstructure. These images were taken by knifemaker Shawn Houston of Triple B Knives:

1425°F, 400°F temper

1475°F, 400°F temper

1600°F, 400°F temper

You can see that the carbide content is significantly reduced by austenitizing at 1475°F as opposed to 1425°F. This significant change in cementite (iron carbide) raised toughness. Then when the temperature is further increased to 1600°F and above, virtually all of the cementite is gone and all that remains is the small volume of hard vanadium and tungsten carbides. The presence of these small carbides is what prevents grain growth even at high temperatures. The carbides “pin” the grain boundaries.

15N20 and L6, in contrast, show a drop in toughness at much lower temperatures because they do not have those carbides to pin grains. The steel 1.2519 does have the W/V carbides but it sees a drop in toughness above 1500°F because it gets excess carbon in solution, leading to plate martensite. The carbon content in ProCut is controlled so that the matrix carbon does not reach excessive levels even at high temperature. This gives ProCut a very wide austenitizing range.

Tempering and Toughness

Like many other knife steels, ProCut sees a peak in toughness with a tempering temperature of around 450°F (230°C). Above that the toughness drops due to a phenomena called “tempered martensite embrittlement” which happens in all steels. There is lower toughness with tempering at lower temperatures as well, of course, corresponding with the higher hardness. The behavior of toughness with tempering temperature is roughly similar whether using the higher or lower austenitizing temperature range.

Hardness vs Toughness

This creates two different heat treating ranges, where the steel can be austenitized high (1625-1675°F) to max out toughness with some cost to wear resistance and edge retention, or austenitizing lower (1475-1575°F) to retain more carbide for wear resistance. The steel still maintains a toughness advantage vs previous tungsten/vanadium steels due to the nickel addition and controlled carbon content with the lower austenitizing range. However, with the high austenitizing range it achieves levels of toughness similar to 8670, 15N20, and L6 but with enhanced wear resistance due to the small tungsten and vanadium carbides.

To compare with other steels you can look at the following chart:

Grinding and Polishing

I don’t have a quantitative test for grindability. Reports from knifemakers so far say that grinding and polishing is very easy with the steel. Some low alloy steels developed for higher wear resistance like CruForgeV are more difficult to polish due to relatively large vanadium carbides that are found relatively frequently. This steel we controlled the W/V content to try to avoid large carbides. Because of the limitations of standard steelmaking (as opposed to powder metallurgy) there are still very occasional larger carbides but they are much rarer than a steel like CruForgeV. So far those few carbides don’t appear to be affecting polishing and finishing.

A lower magnification image of ProCut showing that large carbides aren’t observed most of the time

One of the rare large carbides in ProCut

A micrograph of CruForgeV showing large carbides. Notice there is a magnfication difference vs the ProCut images.

Quenching, Oil Selection, and Hamon

The “hardenability” of ProCut is relatively high, which I also found in testing of 15N20. The high nickel content gives it this hardenability. Air cooling from 1600°F with 1/8″ steel resulted in 60.7 Rc, though from lower temperatures like 1350°F the hardenability is lower (I measured 35.3 Rc). This means that ProCut can be quenched in virtually any quenching oil, even canola, and with relatively thick cross-sections.

This high hardenability means that ProCut is not well suited for developing a hamon. The best choices for a hamon are low hardenability steels like 1095, W2, and 26C3. I won’t say it is impossible to develop a hamon but there are better choices. It is likely still fine for other differential methods like an edge quench.

Forging, Thermal Cycling

Maximum forging temperatures are most greatly affected by the carbon content. High carbon steels are easier to overheat, leading to crumbling while forging. The carbon content of ProCut is limited to ~0.87% so this is not a huge factor with ProCut. For safety I put in the datasheet to limit forging to 2200°F (1200°C). Some knifemakers, especially Damascus makers, push the boundaries of forging temperatures and this can be dangerous. Like with other steels, if you continue to forge when the steel gets too cold this is also a danger in terms of cracking. I haven’t heard a lot of feedback in this area so let me know how the steel behaves for you. The high hardenability means that the steel can sometimes harden in air while cooling from the forging temperature. This can lead to cracking if there are stress risers in the blade.

The “thermal cycling” procedure for ProCut is relatively simple. Like with other steels I prefer to do a single normalize and anneal, so only two steps. I have written about this procedure in past articles. The normalizing step is for dissolving any undesirable carbides and other structures. For this steel it would be in the range of 1600-1650°F where the cementite is dissolved. With a furnace you can hold at this temperature for 10-15 minutes before air cooling. With a forge by eye you just need to heat somewhere into that range or a bit higher.

The annealing procedure is then done by heating to nonmagnetic and slow cooling. I recommend faster cooling rates than is typical for datasheets and this type of anneal is called a “Fast DET” anneal. For simple heat treatments you can slow cool either in a furnace or in an insulating media like vermiculite (available in the garden section of home improvement stores). I tried a range of cooling rates in my furnace. I held the steel for 30 minutes at 1350°F and slow cooled at different rates to measure the annealed hardness. At 50°F/hr cooling the resulting hardness was 23.9 Rc. After 500°F/hr the hardness was 24.5 Rc. I also tried setting the furnace to 1000°F/hr but it only maintained that cooling rate until about 1250°F and slowed from there, the average rate of cooling was about 680°F/hr. That resulted in 26.2 Rc, which is plenty soft enough. Shawn Houston did an anneal with 250°F/hr and he measured 21.2 Rc. Here is the microstructure after normalizing and annealing at 1350°F for 30 minutes, and cooling at 250°F/hr:

Normalized and “Fast DET” annealed microstructure of ProCut (21.2 Rc)

“As-received” annealed microstructure of ProCut (12 Rc)

You can see that the faster annealing procedure results in a finer microstructure which is why the austenitizing response was different (see the prior as-quenched hardness chart). The toughness was still relatively similar despite the very different starting microstructure (see the toughness vs austenitizing temperature chart). Those datapoints were generated using a 100°F/hr anneal which is what I recommended in the datasheet. Somewhat faster and slower cooling rates would have a similar result.

Use in Damascus

The high nickel content means that ProCut is a good replacement for 15N20 or L6 as a bright layer in pattern-welded Damascus. This gives an option for providing higher edge retention whereas 15N20 and L6 have almost no wear resistance apart from their hardness. An initial forging experiment with 1084 and ProCut resulted in excellent contrast:

Edge Retention

Pop’s ProCut did surprisingly well in the CATRA test. The heat treatments performed were 1650°F with a 450°F temper (61.2 Rc), and 1500°F with a 300°F temper (64 Rc). As I have written about before, CATRA is not the best for low alloy steels because the sand particles in the test media are harder than cementite (iron carbides). Even with different media they wouldn’t be at the top of the chart but they would be a bit better. It could be that the relatively low amount of cementite in ProCut helped for the CATRA test. But even if that were the case if we compare with another steel with low cementite content like 8670 or 1095, there was a significant boost to edge retention through the tungsten and vanadium additions. Perhaps with the lower carbon compared with other W/V steels meant that there was less of tungsten and vanadium found in the cementite, allowing them to form more of the hard WC and VC carbides.

Toughness-Edge Retention Balance

With the high toughness plus the unexpectedly good CATRA numbers the ProCut looks very good compared with other low alloy steel options:

Corrosion Resistance

This is a non-stainless steel and should not be expected to be stainless. People say that the 2% nickel in 15N20 gives it somewhat better corrosion resistance than carbon steels but I have not developed a test for comparing corrosion resistance of low alloy steels.

Cryo

There is a certain lore out there with knifemakers claiming that some steels “need” cryo and other steels “don’t benefit” from cryo. Part of this lore is that low alloy and carbon steels are in the “don’t benefit” category. Simple carbon steels and low alloy steels still see an increase in hardness with cryo, typically 0.5-2 Rc depending on the steel and the heat treatment. There is a small cost to toughness because of the increase in hardness. ProCut is the same. As an example of another low alloy steel we experimented with see 52100. I did experiments from 1500°F and 1650°F and found, as expected, that hardness increased. The higher temperature led to a bigger bump from cyro which is also typical. None of the edge retention or toughness tests I showed in the article so far used cryo in any of the heat treatments. But if you want even higher hardness for edge retention and strength you can add a cryo step after quenching.

Comparisons to Other Steels

1084 and 15N20

These steels are relatively “easy” to heat treat in that you can heat them up and quench them and get full hardness. However, they are very easy to overheat leading to grain growth and a drop in toughness. They also have almost no carbide thus having very little wear resistance.

80CrV2

This steel is also lacking in wear resistance though overheating is not much of an issue because of the vanadium addition. It also varies a lot between manufacturers and needs more temperature prior to quenching making it more difficult to perform a forge heat treatment.

52100

In the lower austenitizing range (for higher wear resistance), ProCut compares favorably with 52100 in terms of properties. 52100 has a very good combination of toughness and wear resistance. ProCut is easier to heat treat for an amateur knifemaker and also has the option of the high toughness heat treatment.

O1 and 1095

These are old standard steels. O1 has the benefit of being “oil hardening” so it is easier to quench. I have found both to be very sensitive to overheating because of excess carbon in solution. See my article on O1.

5160, 8670, and L6

These steels have significant chromium additions so they are more difficult to heat treat in a forge. They also don’t have any carbide left over after heat treating and thus their wear resistance is very low.

Blue #2, Wolfram Special, 1.2519

These steels have similar wear resistance for edge retention but significantly lower toughness and do not have the benefits of being beginner friendly.

ApexUltra

This is another low alloy steel I helped develop. It has significantly higher wear resistance and attainable hardness than ProCut, which also means lower toughness. I would recommend ApexUltra for those looking for maximum performance in the “carbon steel” category. Though I wouldn’t call it a difficult steel, it is best for makers that have a bit of experience first.

Heat Treatment Recommendations

In a Forge

Heat to “one shade brighter” after reaching nonmagnetic, quench in oil (most types are fine), and temper twice for one hour each time at 300-450°F (150-230°C) to desired hardness.

In a Furnace

Maximum toughness: 1650°F (900°C) for 10-15 minutes.

Higher edge retention: 1500°F (815°C) for 10-15 minutes

Quench in oil (most types are fine), and temper twice for one hour each time at 300-450°F (150-230°C) to desired hardness.

Thermal Cycling after Forging

1625-1675°F for 10-15 minutes, air cool. Without a controlled furnace, heat into that rough range and establish an even temperature distribution prior to cooling.

1350°F for 30 minutes, cool at 100°F/hr to 1100°F. After that it can be cooled more rapidly. Without a controlled furnace, heat to nonmagnetic and slow cool such as in vermiculite.

Summary and Conclusions

I am happy with how Pop’s ProCut turned out. It offers good balanced performance when compared with other low alloy non-stainless steels. Better edge retention than 1095, O1, 80CrV2, L6, 15N20, etc. And depending on the heat treatment its toughness approaches 8670, 15N20, and 5160. And on top of this it is beginner friendly, being easy to heat treat, grind, and finish.

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