Wide Release Date for MagnaMax for Small Knifemakers

MagnaMax will be on sale May 1st, 2026 at 9am on Niagara Specialty Metals’ online store: https://nsm-ny.com/shop/

You can create an account beforehand so that you are ready to buy once the steel goes live. We made the following commercial to get pumped for the release:

Intro

I wrote an article (and created a video) about MagnaMax properties a few months ago. So I won’t be rehashing all of the properties here. Basically, MagnaMax is designed to have enhanced wear resistance and edge retention vs MagnaCut with similar corrosion resistance and hardness potential.

You will also see in the chart above that MagnaMax offers superior toughness and edge retention to the popular M390 and 20CV. It is very difficult to improve both of these properties at the same time, so this is a big improvement. It also maintains similar toughness to grades CPM-154, S35VN, and Vanax, which were formerly the toughest PM stainless steels prior to MagnaCut. So it offers a significant edge retention improvement to those grades, which have had a reputation for good properties in the past.

That property summary article did not have specific heat treatment recommendations because I was waiting on the final material. The initial heat of steel had carbon on the low end of the specification, so it wasn’t as representative of the average material as I wanted. No change was made to the target composition or the specification, it just landed at the lower end for carbon. So now that I have received and tested material closer to the midpoint of the specification I performed a more comprehensive set of tests. Knifemaker Matthew Gregory helped to make the majority of the toughness coupons.

High Level Heat Treatment Summary

Before we get into all of the details I can give a simple summary so you don’t get lost.

With Cryo:

Austenitize 2100-2250°F (1150-1230°C). The baseline temperature for good properties is 2150°F (1175°C).

Plate quench for faster cooling and slightly higher hardness.

After cooling to approximately room temperature, place immediately in liquid nitrogen. The amount of time it sits in the liquid nitrogen doesn’t matter that much, it just needs to reach the temperature. An hour is fine. What does matter is not wasting time before putting it in the liquid nitrogen. You don’t need to check the hardness beforehand.

Temper 300-450°F (150-230°C) twice for two hours each time. 350°F (175°C) is a baseline temperature for good properties.

Without Cryo:

Use your household freezer. It is a myth that it doesn’t have any effect. There is no reason to do no cold treatment. Everybody has or can get a freezer. Dry ice is even better, but despite being about 100°F colder than a freezer often behaves closer to a freezer than to liquid nitrogen.

Austenitize 2050-2100°F (1120-1150°C). 2100°F (1150°C) is a good temperature. It might be possible to go somewhat higher but I worry about excess retained austenite.

Plate quench for faster cooling and slightly higher hardness.

After cooling to approximately room temperature, place immediately in the freezer or dry ice. The amount of time it sits in the freezer doesn’t matter that much, it just needs to reach the temperature. An hour is fine. What does matter is not wasting time before putting it in the freezer. You don’t need to check the hardness beforehand.

Temper 300-450°F (150-230°C) twice for two hours each time. 350°F (175°C) is a baseline temperature for good properties.

Austenitizing hold times:

The required hold time changes with temperature. This is the soak time required after the piece reaches the temperature. It rarely hurts to add extra minutes, it is more common to have an issue with undersoaking.

2050°F (1120°C): 20 minutes

2100°F (1150°C): 15 minutes

2150°F (1175°C): 10 minutes

2200°F (1205°C): 5 minutes

2250°F (1230°C): 5 minutes

Hardness and Cryo

I first made a series of coupons to test the hardening response, including with the addition of a freezer or liquid nitrogen treatment after quenching. I used the soak times in the section above.

You can see that with no cold treatment the peak hardness was 2050°F (1120°C) after tempering at 300°F (150°C). Hardness drops with higher temperatures from excess retained austenite. Hardness rose when using liquid nitrogen all the way to 2250°F (1230°C). It would be unlikely to keep rising much beyond this temperature and the possibility of melting grain boundaries starts to become more of a danger. The freezer also rose all the way up to 2250°F but to a lesser extent. Because the increase was small beyond 2100°F (1150°C) this is why I limited my recommendation for the freezer to that temperature. That makes me think both the retained austenite and hardness of the martensite were increasing beyond that temperature, leading to relatively flat behavior. Excess retained austenite can lead to worse sharpening behavior when deburring. Overall this hardening response is not radically different than MagnaCut.

Nothing too crazy showed up in the tempering. You can see that a cold treatment leads to less hardness loss in tempering. Compare 2050°F with and without a cold treatment, or 2100°F with liquid nitrogen vs the freezer. Note that I have a single curve for both freezer or liquid nitrogen from 2050°F, and this was because the two were sufficiently similar to have a single line. Plus don’t want to make the chart too busy.

You will also notice that the hardness reaches an initial minimum at 600°F (315°C) and then rose to a secondary peak around 900°F (480°C). This is known as “secondary hardening.” I don’t recommend tempering in that range, especially with stainless steels, because it reduces corrosion resistance. For example see two Vanax coupons below, both sprayed with 1% saltwater. The one of the left was tempered at 400°F (200°C) and the one on the right was tempered at 1000°F (540°C).

Toughness

We also tested a series of charpy toughness coupons for this heat of MagnaMax. I used my standard coupon which is quarter size (2.5 x 10 mm) and unnotched. Three coupons were tested for each condition. We used liquid nitrogen in the heat treatment of all of these coupons directly after the quench. We used austenitizing temperatures of 2000-2250°F (1095-1230°C) and tempering temperatures of 300, 350, and 450°F (150, 175, 230°C).

The hardness was slightly lower than the small hardness coupons I showed results from before:

Looking at the resulting toughness, it rose from 2000 to 2050°F (1095 to 1120°C), was relatively flat up to 2200°F (1205°C), and then dropped somewhat up to 2250°F (1230°C). This is why I recommended a baseline austenitizing temperature of 2150°F (1175°C) as this appears to be roughly the peak hardness-toughness, though an argument could also be made for 2200°F (1205°C), in part due to a couple of the 2150°F results being on the low end and a couple of the 2200°F being on the high end. This is likely due to statistical variability of testing.

You can also see that toughness increases with tempering temperature as we would expect, which also corresponds to a hardness decrease. Lower hardness generally correlates with higher toughness.

There was a greater increase in toughness between 300 and 350°F (150-175°C) than between 350 and 450°F (175-230°C), which is why I recommended 350°F (175°C) as the baseline tempering temperature.

Hardness-Toughness Balance

But what we would like to maximize is the highest toughness for a given hardness. So I plotted hardness vs toughness below.

You will notice that the maximum hardness-toughness combinations were generally 2150-2200°F (1175-1230°C) and tempering at 350-450°F (175-230°C). The exceptions include: 1) 2100°F (1150°C) with 450°F (230°C) because that combination gave the best properties for lower hardness. And 2) For maximum hardness you need 2150-2250°F (1175-1230°C) in combination with the minimum tempering temperature of 300°F (150°C). I next overlaid those best heat treatment conditions on top of the similar non-stainless steels K390, Vanadis 8, and CPM-10V:

Erasteel MM#1 is the first heat that was shown in the prior article about MagnaMax properties, and Erasteel MM#2 is the final tested material above. You can see that both have a similar hardness-toughness balance, though the new one is skewed to somewhat higher hardness, as expected from more carbon. You will also see that the toughness is very similar to K390 and Vanadis 8, an excellent result given that MagnaMax is a stainless steel with similar wear resistance. So we greatly improved corrosion resistance over those steels while maintaining their other properties. I next plotted those hardness-toughness values vs other stainless powder metallurgy steels:

You can see that MagnaMax has superior hardness-toughness than virtually all of the powder metallurgy stainless steels apart from MagnaCut. This includes steels with a good reputation for toughness including Vanax, XHP, S35VN, and CPM-154. And below I have the more complete graph of stainless steels which is a bit busy:

Corrosion Resistance

I compared the final higher carbon version of corrosion resistance to the earlier and both passed the 1% saltwater corrosion test. Showing a picture of two clean samples isn’t very interesting, so here is the earlier image of MagnaMax vs other steels:

Each of those was austenitized from 2150°F (1175°C). MagnaMax (and MagnaCut) were designed for all of the chromium carbides to be dissolved around 2050°F (1120°C). After the chromium carbides are dissolved the corrosion resistance doesn’t appreciably change with even higher temperatures. This is different than most other stainless steels which have chromium carbides all the way up to the melting temperature. But using even higher than 2050°F does provide some factor of safety, better ensuring the chromium carbides are fully dissolved.

The other main factors for corrosion resistance are quench rate and tempering temperature. I mentioned in the tempering section that tempering above about 750°F (400°C) leads to a reduction in corrosion resistance and I showed a test with Vanax to illustrate that. Quenching isn’t an issue unless it is very slow, which leads to carbides precipitating on the grain boundaries which can reduce corrosion resistance.

Edge Retention

The primary factors for edge wear resistance are carbide volume, carbide hardness (controlled by type), and steel hardness. While the carbides are very important when comparing different steels, there is less of an impact within a given steel. It is true that austenitizing higher dissolves a bit more carbide but this effect is generally drowned out by the increase in hardness. So in general, achieving a higher hardness results in greater edge retention, and there isn’t much point in worrying about the exact austenitizing and tempering temperatures that were used to get there. I have the graph below of CATRA results I tested previously to show where MagnaMax lands and the effect of hardness on the results:

Summary and Conclusions

So I have shown the majority of the heat treatment data that I generated and my reasoning for the different recommendations. I am overall happy with how the heat treatment response ended up. If you want to see the simplified heat treatment recommendations, scroll back near the top where it said “High Level Heat Treatment Summary.” Hopefully that is simple enough for everyone. If not then ask questions in the comments. MagnaMax will be on sale May 1st, 2026 at 9am on Niagara Specialty Metals’ online store: https://nsm-ny.com/shop/

The post How to Heat Treat MagnaMax Steel appeared first on Knife Steel Nerds.

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.

Thanks to my Patreon supporters for supporting knife steel research. Patreon supporters saw this interview a couple of days ago. You can see the latest results of my testing early if you join at Patreon.com/KnifeSteelNerds

Video Interview

Transcript

I made some tiny edits for clarity and removed a lot of “um”s and “you know”s and repeated words but otherwise I left the interview alone.

Larrin Thomas:

I’m Larrin. This is Knife Steel Nerds. I have with me Bob Shabala of Niagara Specialty Metals. And we have a lot to talk about in the wake of the Crucible bankruptcy, and a lot of things that are happening right now. So, Bob, could you start out by telling us your position at Niagara and some of the history of Niagara Specialty Metals?

Bob Shabala:

Sure. Yeah, thanks for having me on. I’m the president and CEO of Niagara Specialty Metals. I’ve been here for 31 years. Niagara Specialty Metals started in 1982 by two gentlemen, Barry Hemphill and Lou Valery, primarily as a mill to service the tool steel industry. They bought slabs of steel and hot rolled it into sheet or plate. Quickly, it grew into more of a service company where people would send them material to roll and ship back to them. Then over time, we expanded capabilities to be able to process stainless steels, aerospace alloys, titanium, maraging, and the cutlery grades that are of interest here today.

In 2009, Crucible was our biggest customer. They went bankrupt the first time, and we came to an agreement where they would supply us with all the CPM alloys, and we could market them and sell them to whoever we want.

So from 2009 until present day, they were our sole supplier of PM alloys. They were great to work with, they were very responsive. But we could see the writing on the wall starting last year that things weren’t going well and that they were in trouble. So that’s when we started reaching out to other suppliers to, uh, to get us the steel we need for, for this market.

In addition to that, we have 40 employees. In 2004, Barry Hemphill was the remaining sole owner of the company. He essentially gave it to the employees. He turned it into a 100% ESOP (Employee Stock Ownership Plan). So everybody working here is an owner of the company. So when they retire, we buy the shares back from them, and it’s worked out very well for all the employees that are here. So when it comes time to fill positions, it’s not easy, but it’s easier than most places. And typically, once we get somebody in here working and they understand the value of the ESOP and working for a small employee-owned company, they tend to stay for a long time, which is great. We have very minimal turnover, so we can take our time training somebody because it takes three to five years to train somebody on all the jobs we have here. So the model has worked out very well for us.

Larrin:

So you mentioned PM alloys. That refers to powder metallurgy alloys, or specifically (in this case) steels for the knife industry. And Crucible invented that technology back in the late 60s, early 70s. And so they had a great legacy of making those steels. You know you had other suppliers for regular conventional steels, which are ingot cast, right? And so, powder metallurgy, a lot of the best knife steels are made with powder metallurgy. So anything with a CPM in front of it was powder metallurgy. So many of the best steels like S30V, S35VN, MagnaCut, you know, those are all powder metallurgy. So, Crucible going away is kind of a blow.

Another thing I want to hear about a little bit is the unique capabilities of Niagara. There’s really not any competitors in the USA for what you’re doing, right? What makes it so challenging to hot roll steel for knives?

Bob:

So for our initial rolling operation, we would just call it the plate mill. It’s in a fairly small area compared to most big mills. So we have the unique ability to reheat. So, take a grade like Rex 121 or Rex 76, we might have to reheat those plates every two or three passes. So we’re able to do that, whereas some mills, once you take it out of the furnace, they can only roll it so far and then that’s it. It’s also a hand mill, so we can take anything from 100 pounds up to 3,000 pounds and roll that into a different dimension. When we buy slabs, they start out anywhere from three to six inches thick. So if we’re rolling down to anything less than a half inch, what we do is roll it to an intermediate size. Then we anneal it to soften it back up. We’ll de-scale it to clean the surface, send it down to our sheet mill where we then reheat it again, finish roll it to size, anneal it, flatten, and ship.

I guess people don’t do what we do because the quantities are relatively small. We take on anything from one piece to a truckload, and our ability to deliver on time and relatively quickly is hard to beat. So that’s why we have this small segment of the market kind of, not to ourselves, but, why we’re doing well with this kind of product.

Larrin:

So I know for the steel that I developed, MagnaCut, a major reason why I was able to make it happen is because I got your buy-in early on. Crucible was a bit skeptical of trying a grade that I designed since I had not designed any tool steels or stainless steels before. So I know you guys have had a big commitment to the knife industry. Getting steels from other companies is often challenging because a lot of times, they’re sitting around in several-inch-thick pieces. So I think that’s awesome that Niagara has been so good. And the reason why we have a lot of these awesome grades is because Niagara is able to roll them and deliver them, at a good pace, like you said.

So Crucible, you hear, they’re maybe not doing well. So, what was your approach next? What did you start doing to make sure that we weren’t losing out on everything?

Bob:

Sure. Yeah. So last January, January 24, we started increasing our inventory with Crucible. So we started ordering more than we needed to, to kind of boost the inventory. And then, last fall, just in discussions with Crucible, we knew they were for sale. They had announced that. And I asked the president of the company in my position, should I start looking for other places to buy steel? And he said, yes. So I give him a lot of credit that he didn’t try to hide the fact that they were in a desperate time.

So we already had relationships with Carpenter Technology. We’ve processed millions of pounds for Carpenter and Erasteel for other industrial customers. So we, we reached out to both mills, explained our situation, and they were happy to help. So they both right away started looking into the ability to make MagnaCut. Because that’s our most popular grade right now. Erasteel already makes a version of CPM 154. So we ordered test heat of those grades from both mills. And they’ve been fantastic. You know they basically have delivered when they said they were going to deliver. We know the quality is good. It’s just a matter of ensuring that chemistries from different mills, you know, certs are, they don’t read right or they don’t read exactly the same. There might be some offset between mills. So, before we start releasing anything to the public, we want to make sure that it performs like it should. And we really should have everything ready to go here in the next next quarter or so.

Larrin:

So what you’re talking about is that different mills have different equipment for measuring the composition of the heats. And those pieces of equipment can be calibrated somewhat differently. And so one mill might measure 14% chromium and another might read 14.5% chromium for the same thing. And so if you’re then trying to transition grades over between companies, it might behave slightly differently if they have the same composition target. So we’re trying to work on any offset that might be necessary. Not that there would be a problem with a grade with a slightly different composition, but if all of your customers are used to heat treating at specific temperatures, and then it starts heat treating as if you’re 25 or 50 degrees hotter, you know that could be an issue for them if all the steel’s coming out different.

But the quality is high from Erasteel and Carpenter. They have a good reputation for making powder metallurgy steel.

Bob:

Yeah. Yeah. For years, Carpenter would send us their cutlery alloys in addition to aerospace and tool steel. So I think all of the XHP that’s ever been processed and sold to the market has been rolled here in Niagara Specialty, and we’re now stocking it. They felt that they would have better success or move more XHP if they would just sell us the steel and let us sell it to whoever we want. So that’s starting to take off. We also have their version of S90V, 10V, M4. So, yeah, it rolls really nice. There’s really no issues with it at all.

Larrin:

Well, I know XHP, which is a powder metallurgy stainless steel used in knives, that it has had a reputation for being difficult to obtain or having inconsistent availability. And I do think that’s one thing that Niagara has maybe been the best at is just having steel in the sizes that you want available to buy. When you call up these steel companies and they say, yeah, we can get you XHP, just you need to order many tons of it, and then you need to wait a year, it’s not very enticing. And if you’re a small custom knife maker, then obviously it’s just a total no-go. It’s impossible.

So what about our ability to make new alloys? We’re trying to make a new steel with the same concept of MagnaCut, but with improved wear resistance called MagnaMax. Are we going to be able to make that happen now that Crucible is gone?

Bob:

Yeah. So that’s a grade that, thanks to you, we had a prototype heat or an initial two heats made at Crucible, and the feedback’s been great. So, we patented it with you. We also trademarked it. So that gives us the ability to buy from both mills. And they both are getting ready to make it. So by, I think, the fourth quarter this year, we should have heats from both mills ready to go. As far as future alloys go, it’s something we’ll have to discuss with them. You know, our primary concern right now is getting the grades that we’ve always sold and making sure they test out and we get them locked in. And then we can have discussions with them about making new grades as you develop them.

Larrin:

So I guess we haven’t said explicitly that Erasteel bought the IP of Crucible CPM alloys, so all their powder metallurgy alloys. So that includes trademarks and also patents. Though there’s not very many patents remaining because all of the patents date back to before Crucible’s first bankruptcy in 2009. Is there any chance that Crucible will come back, or are they just Erasteel now?

Bob:

I think they’re just Erasteel. I don’t know all of the particulars of what’s going on inside the Crucible facility, but I just don’t see that getting started back up. In fact, I don’t see any domestic companies getting ready to atomize iron-based alloys that would be used in cutlery. There’s atomizing for nickel alloys and maybe titanium, but, um, iron base, I think, is just such a small portion of the overall steel industry. Nobody’s going to put the kind of money into it that they would be required to, and to bring that back on shore.

Larrin:

Well, that would be very disappointing. Nickel and titanium alloys, they have higher profit margins, which might explain why they prefer to make those, even if they have atomization equipment.

So, are we going to continue to make all these grades? I mean, Crucible had… a ton of grades, S30V, S35VN, S45VN, S90V, (etc.) there are so many. Are we going to be able to keep all of those, or are we going to need to simplify the portfolio?

Bob:

We could, in theory, buy them all. Except for 15V, I think that the atomizing temperature on that is higher than what Carpenter or Erasteel can do in their atomizing furnace. They both have said that they can’t make 15V. So until we come up with an alternative there, I think that grade’s going away. But yeah, everything else we could buy. I mean, I think that once MagnaMax comes out, we will take a look at the existing grades in our portfolio and decide if some should be obsoleted. You know, we tried to bring S6 V back a few years ago. We bought a small heat and half of that heat is still here. That didn’t work out. Sales of 20CV have slowed down. So that might be a potential candidate to not buy anymore. But we still sell a lot of CPM-154, S30V, S35VN, S45VN. So I don’t see any of the major grades going anywhere anytime soon. And they’re all on order. We have all those grades on order with Erasteel at this point.

Larrin:

So, how is branding going to work going forward? Are you going to use the same names, or are some grades going to have different names?

Bob:

Yeah, so anything we buy exclusively from Erasteel will retain the CPM grade name. We’re not going to enforce (the prefix) CPM. So if people want to buy S30V, I think we’ll just be calling it S30V. And that satisfies everybody. CPM CruWear, because of an existing agreement they have with another company, we’re going to have to rebrand that. You know, that’s still a big moving grade for us. They currently make that same composition. They have been making it for years. So we’re going to buy that, and it would just be rebranded NSMWear, unless somebody can give me a better name. S90V is not a real big grade for us. And we have a lot of that in stock from Carpenter that we bought during COVID as a way to let Crucible focus on cutlery grades. We had placed orders for industrial grades with Carpenter. So their name for that is CTS 420CW MOD.

Larrin:

And that is not a good name.

Bob:

And I don’t see anybody putting that on a knife blade. So I think we’re going to rebrand that as NSM90 and just try to make sure everybody understands it’s the exact same composition, or virtually the same exact composition, as CPM S90V. So those two grades we’re going to rebrand and see how it goes. And that gives us the ability then to buy from both mills and be single source like we were with Crucible.

Larrin:

So we’re going to have continued availability. Niagara, they’re a great American company specialized in rolling these difficult grades to thin sizes that we need for knives. Everything is in motion to continue. Is there a chance that there is a gap in availability, or is it going to be a smooth transition?

Bob:

Yeah, there’s going to be some disruptions, almost certainly. I think once people found out that Crucible is going out of business, there’s some panic buying. So hopefully everybody has what they need for the next five or six months, but everything except for a CPM-154, MagnaCut, we still have plenty of stock to get us through for the next several months. It’s just a matter of getting in these initial heats, getting them approved. And once that happens, it’s full speed ahead. So I think that the next quarter or so, there are going to be disruptions almost certainly. But once approved, I think that Erasteel and Carpenter both are really looking forward to participating in this in a meaningful way. And they’re here to support us and the whole knife community.

Larrin:

Well, that’s great. I am biased, but I think Niagara is an awesome company and a major reason why we have so many knife steels available in a good range of sizes.

Bob:

Thank you.

Larrin:

So I’m happy things are continuing. I’ve gotten messages from a bunch of knife companies that are freaking out, worried that stuff isn’t going to be available anymore. I keep telling them that Niagara is going to keep stuff going and not to worry.

So hopefully we can quell some of those fears. Supply is going to continue. I think people didn’t always realize that, yes, like Crucible was making the powder and sending slabs to Niagara, but Niagara is the company processing all this steel and selling it all. So hopefully we can get the word out that Niagara is a great company that is delivering all these steels, and Niagara is still here and Niagara is doing well and continuing to make these steels.

Bob:

Yeah, we’re financially very sound. You know, the people we have working here, they’re awesome. I mean, they really make it happen. You know when we have something important, like a new heat of MagnaCut coming in from Erasteel and we need to get it approved, they’re right on it. Literally unloading it from the truck and putting it on the saw and cutting it into blocks to get it rolled the next day. So they really are invested in (the) success of the company and the industry as a whole. So yeah, we’re here for the long haul.

Larrin:

And Niagara’s made some upgrades in recent years, right?

Bob:

Yeah. We did our biggest project ever last year. It’s still in process, but for us it was big. I mean, it is about a $7 million investment. So we added about 15,000 square feet to our sheet mill building. And then we had six small electric box furnaces that they did the job for several years, but the heat in them could be uneven. The elements were delicate and expensive to replace. And it was a bottleneck. The guys could work faster than the furnaces. So lots of times they’re just waiting for the steel to heat up. So once we got the building built, we put in a continuous gas furnace. So now the sheets are in the furnace for 25 to 35 minutes instead of three hours. And the temperature on the blanks is really uniform from front to back and side to side. So the gauge coming off our mill is much more even and easier to control. The surface is a lot cleaner. There’s no scale because it’s not in the furnace as long.

And then the last step of the process is going to be a new housing for the rolling mill itself. So the housing is essentially the structure that holds the rolls and the rolls are, rotating and feeding; that’s where the steel goes through to get reduced. The new housings are complete, but we’re not ready to put them in here yet. We need another month to get all the wiring in place and control panels. So around Labor Day, we’re going to install that. So there we’re going to increase our separating force. There’s going to be some machine learning on it so we can put in recipes. Right now, we just turn the dial and get it to where we think it needs to be, and then we have to check the gauge. So in the end, once that comes in, with the much stronger housing, it should be higher throughput, even more uniform gauge from piece to piece.

So that was a real big investment for us. In addition, we’re getting ready to put on another, I think about 12,000 square foot building for our grinding operation. We have a Blanchard grinder for grinding our sheets to size that’s starting to get a bit of a bottleneck. So we already bought another Blanchard grinder, 84 inch diameter that’s in storage until the building gets built.

We have a fiber optic laser that we can cut up to about 3/8 of an inch and we use high-pressure nitrogen in that. So we cut a lot of knife blanks for the industry now. And that’s starting to get busier. So we cut for small shops that give us a DXF file, we can cut their blanks for them. And (that) saves them shipping whole sheets to a laser shop and then taking the blanks to their place. So kind of a one-stop shop here. So with that filling up, we want to get another laser to put in the new area. And then outside of the cutlery industry, we do a lot of bandsaw cutting. So we roll a lot of big heavy plate, or people send us their plates, and we saw cut it into either small rectangular shapes or strips or full-size plate. So over the past couple years, we’ve spent two to three million dollars in in bandsaws just upgrading our cutting capabilities.

Larrin Thomas

Wow, on bandsaws.

Bob

Yeah. There we have two of them now, they’ll cut in two directions. So all of our bandsaws to date either just cut along the length of a plate or across the end. These two axis ones, we can cut the ends first, then the head goes back, and then it’ll just strip it out. So just put the plate on there one time and you’re done, essentially let the machine do the work. So it just makes it easier to get accurate cuts. The guys like it cause it’s safer, a lot less handling moving plates around. So, yeah, that’s been a big part of our business.

Larrin

Well, thanks, Bob. Hopefully, we answered people’s questions and didn’t just add to the confusion. So we’ll have to bring you back on if we get a lot more questions based on the interview. But thanks for joining me and talking about Niagara and the whole plan for keeping knife steel going.

Bob

All right, anytime. Thanks, Larrin. I appreciate it.

The post The Future of Knife Steel with Bob Shabala of Niagara Specialty Metals appeared first on Knife Steel Nerds.

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Update: Artisan Cutlery posted to their Instagram confirming our findings:

View this post on Instagram

A post shared by ArtisanCutlery (@artisancutlery)

Video

There is also a video of the following information:

AR-RPM9 Announcement and Name

AR-RPM9 was first announced in June 2020 on the CJRB Instagram, though oddly their Instagram doesn’t seem to go back that far now. I have a screenshot of it here:

CJRB is another brand owned by Artisan Cutlery. AR-RPM9 stands for “Artisan-Rare Powdered Material 9 Element Steel.” That is a very odd name so let’s break it down one element at a time. Artisan makes sense, it refers to Artisan Cutlery. But why “Artisan-Rare”? Just to have an oblique reference to AR rifles? I honestly don’t know. Then “Powdered Material” is odd, generally when we say “PM” steel that means “Powder Metallurgy” or “Particle Metallurgy” but not “powdered material.” In my original Patreon post about this steel I hypothesized that perhaps they were using weasel words for some other process that isn’t powder metallurgy but then they released a video in September 2020 where they specifically called it “powdered metallurgy” process, but we will come back to that. Then “9 Element Steel” which is a good lead-in to the composition discussion.

Composition of AR-RPM9 (Why it should actually be called AR-RPM7)

Artisan Cutlery revealed the composition of the steel in that September 2020 video. I was excited to see what it might be since they claimed to have designed a “new exclusive steel” designed specifically “with our…knives in mind.” Plus nine elements is quite a bit, so they must have gotten very creative in the design of the steel. Unfortunately, the reveal was quite underwhelming. The composition they specified was identical to the common 9Cr18MoV, the same steel as the European 1.4112, and very similar to American 440B. There were a few oddities in the description. One of the elements the video said was part of the 9 was “less than 0.4% nickel.” That is the same maximum allowable nickel content in 9Cr18MoV. Having a maximum allowable content means that it isn’t intentionally added; there is no minimum requirement. This is because nickel is present in a lot of recycled stainless steel. For example, I measured between 0.16 and 0.28% nickel in stainless powder metallurgy steels from Crucible, Carpenter, Bohler, and Uddeholm. So we are already down to 8 elements not nine.

Measurements of nitrogen, copper, nickel, cobalt, and tungsten in a range of powder metallurgy steels

Another oddity in the Instagram video was that he said there were “rare earth elements” in the steel, with elements plural so potentially we are back up to 9 or maybe even more. Before saying what those rare earth elements were, the Instagram video cut off. Rare earth elements are used in some steels and include elements like lanthanum and cerium, used for a couple different reasons in the steelmaking process. So a pretty unusual addition, especially to announce publicly, as often they are used without advertising to the public, in part because it is a trade secret and in part because they are used in very small amounts. Fortunately, Artisan Cutlery later clarified to Knife Newsroom shortly after what these elements are, and even later in December they uploaded a full version of the cutoff instagram video to YouTube. The answer was baffling: phosphorus and sulfur. Phosphorus and sulfur are not rare earth elements. I have never heard anyone say they are rare earth elements. Those are common impurity elements that are often specified with a maximum allowable content. They are not desirable, and are not considered an addition to the steel. So now we are down to 7 elements. We need to rename the steel AR-RPM7.

The only potentially relevant change is cobalt, which they said is 0.3%. 9Cr18MoV doesn’t have a cobalt specification, and 0.3% is a very small amount, so an argument could be made that it would still fit under the 9Cr18MoV spec. Cobalt is also present in a lot of recycled steel, so there is generally at least a small amount of it, though usually less than 0.3%. Furthermore, an addition of 0.3% cobalt to a steel would have a very minor effect on properties. Even with controlled testing of properties with and without 0.3% cobalt I’m not sure a metallurgist could come up with which is which. So maybe this is the change to 9Cr18MoV that they thought was enough to be a “new steel.”

I measured the composition of the steel with Optical Emission Spectroscopy (OES) and the elements were within expected ranges. Of course other trace elements were present which is also expected but I have not included them so as to not confuse anyone.

Powder Metallurgy? (Why we can’t call it AR-RPM7 either)

In my original Patreon article in June 2020 I expressed skepticism about AR-RPM9 being powder metallurgy. Artisan Cutlery already misunderstood how many elements were in their steel and apparently have no idea what a rare earth element is, so the chances they know what powder metallurgy is seemed small. Furthermore, there are several steels made in China using “Sprayform” which is a different technology than “Powder Metallurgy.” One example that has come out since AR-RPM9 is Twosun Knives YJ01-V1 which is a sprayform version of a slightly modified M390. This steel is made by Foshan Fenghe PSF (Precision Spray Form).

What is Spray Form?

Sprayform is an intermediate technology in between conventional casting and powder metallurgy. In conventional casting, the liquid steel is slowly cooled in a mold to form an ingot. The slow cooling leads to alloy segregation and large carbides. With powder metallurgy the liquid steel passes through a nozzle and is sprayed with nitrogen gas to rapidly solidify (gas atomization) the steel into fine particles (powder), which is then placed in a canister under high pressure and temperature called hot isostatic pressing (HIP) to create a solid ingot. The steel is then forged and rolled like normal. I previously wrote about powder metallurgy in this article.

Sprayform is somewhat similar to powder metallurgy in that the liquid iron is sprayed with nitrogen gas, but instead of fully solidifying, the partially solidified steel is sprayed onto a table which lowers during processing to create the entire ingot. This leads to an intermediate microstructure which is not as fine as powder metallurgy but also not as coarse as conventional steelmaking. I have an article comparing D2, sprayform D2, and powder metallurgy D2. Below are micrographs showing the difference in D2 microstructure with the three different technologies:

Conventional D2

Sprayform D2

Powder Metallurgy D2

As one more example, here are micrographs from Fenghe PSF showing their ripoff of M390 made with sprayform (right) compared with the powder metallurgy version (left):

Powder Metallurgy M390 (left) and Sprayform M390 (right)

You can see that the carbides in a sprayform steel are in between powder metallurgy and conventional. Sprayforming is done because it is lower cost vs powder metallurgy, eliminating the HIP step.

What Technology is Used for AR-RPM9?

So Shawn Houston of Triple B Handmade and I bought a couple knives from Artisan Cutlery to investigate the microstructure.

High Magnification (same as prior D2 micrographs)

AR-RPM9 Medium Magnification

Here is Sprayform D2 for comparison:

Sprayform D2 Medium Magnification

It is evident immediately that this is certainly not a powder metallurgy steel. There are many large carbides that I have never seen in any PM steel. I don’t believe that it would be possible to make a PM steel with carbides that large. With the largest carbides being around 10 microns I think sprayform is the most likely, though I could almost be talked into it being a conventionally produced steel. To compare the carbide size with 9Cr18MoV, the conventional version of this steel, we looked at edges of knives in both steels:

AR-RPM9 knife with relatively small carbides visible

9Cr18MoV knife with relatively large carbides visible

The carbides appear larger in the edge of the 9Cr18MoV knife when compared with the AR-RPM9. And the carbides in the AR-RPM9 look much too large to be powder metallurgy. So I think sprayform is the most likely production technology.

Changing the Name of AR-RPM9 to ASF7

We already discussed how the “9” should actually be a “7” in AR-RPM9, but let’s analyze the rest of the name: “Artisan-Rare Powdered Material 9 Element Steel.” We can leave the “Artisan” since that is the company selling the knives. The “rare” part I take some issue with, so we can drop that from the name. And I have discussed how “Powdered Material” is misleading so we can drop that. So we will rename the steel “Artisan Spray Form 7 Element Steel” or ASF7 for short. There, we fixed it. No more false advertising.

Properties of AR-RPM9

So now that we have discussed what AR-RPM9 likely is (and what it isn’t), what are the properties of the steel? Sprayform technology does improve toughness, though not to the extent of powder metallurgy. You can see an example with D2, sprayform D2 (PSF27), and powder metallurgy D2 (CPM-D2):

So we would expect a similar improvement over 9Cr18MoV, which would have similar toughness to 440C which I have already tested:

With 440C being around 6 ft-lbs at 59 Rc, we would expect AR-RPM9 to be in the 8-12 ft-lbs range. Nothing too spectacular but that’s what the main improvement would be over 9Cr18MoV. In terms of hardness, edge retention, and corrosion resistance, any differences would be minimal. You can read an article where I compared the edge retention of conventional and powder metallurgy 154CM to see why I think so (they performed the same). If you want to estimate the edge retention of AR-RPM9 vs other steels in my big CATRA chart you can look at 440C, or possibly a bit less.

Summary and Conclusions

AR-RPM9 is very poorly named, having only 7 elements and likely being made with sprayform but not powder metallurgy. It is essentially a sprayform version of 9Cr18MoV. Despite their claims, this steel isn’t “new” nor is it particularly exciting. The sprayform technology likely improves the toughness somewhat but wouldn’t impact much else.

The post AR-RPM9 Knife Steel is False Advertising appeared first on Knife Steel Nerds.

Thank you to all the new Knife Steel Nerds Patreon supporters! Your support allows me to do new exciting experiments on knife steel. Some exciting ones coming up in the coming months!

Video

I also have a video which covers the same information (more or less) in this article.

Intro

Jim Sutton of Zapp Tooling Alloys contacted me recently to talk about testing their Z-Wear. Zapp has previously purchased their powder steel from a USA company, and they are adding a European steel company as another source. They wanted to compare the properties between the two suppliers to ensure they are equivalent, and/or to determine if one is better than another. Some companies have claimed that their powder metallurgy process is better than other companies, notably Bohler and Uddeholm (of the parent company voestalpine) claim their process is “3rd generation” for a finer powder size and lower “inclusions” in the steel [1]. I previously compared the inclusion content and properties of Bohler, Uddeholm, Crucible, and Carpenter powder metallurgy steels in this article. Bohler-Uddeholm has previously claimed that Erasteel uses “2nd generation” technology, though Erasteel has since made improvements to their process which they call Dvalin which makes similar claims to reduction in inclusions to Bohler-Uddeholm:

Common impurities in steel include sulfur (S), phosphorus (P), and oxygen (O). My testing found P and S to be similar among the manufacturers, but oxygen content to be somewhat lower for Bohler and Uddeholm, Carpenter to be the worst, and Crucible in the middle:

That prior article also has micrographs of polished specimens of each where you can look at the impurities themselves. None of them looked particularly “clean” but you can look at the micrographs and decide for yourself.

However, these differences did not lead to a difference in measured toughness, as M390 and 20CV had the same toughness:

As a side note, I found this austenitizing temperature of 2140°F to be too high leading to inflated toughness, which you can read about here. Also the reported finer powder size did not lead to an obvious difference in carbide size:

M390

20CV

A much bigger effect than powder size is carbide type. The similar CPM-4V (Crucible) and Vanadis 4 Extra (Uddeholm) have only vanadium carbides, and their average carbide size is much smaller than either M390 or 20CV:

Vanadis 4 Extra

CPM-4V

And when testing the toughness of those two grades there was no advantage to the Vanadis 4 Extra. In fact the CPM-4V had greater toughness in the one condition that was the same between the two (1975°F austenitize, 400°F temper, transverse testing direction). However, this was due to small composition differences between the two grades. The CPM-4V had lower carbon so resulted in slightly lower hardness but better toughness.

The only comparison between manufacturers involving Erasteel I have performed was of RWL34 (Erasteel) and CPM-154 (Crucible) which are basically identical. In this case the Erasteel had slightly higher toughness. This was part of a study of Damasteel stainless Damascus which you can read here.

However, all of these tests were done with my normal average of 3 or 4 toughness coupons. Perhaps the difference in toughness would only show up with more coupons tested, looking for one-off coupons with a large oxygen inclusions, so I suggested to Zapp that we test 9 coupons from each manufacturer and determine if there were any clear differences between the two.

Z-Wear

I previously tested Z-Wear, which you can read here. That study was done with knifemaker Warren Krywko, and we found a few key things:

1. A “low” temper of 400°F led to a better balance of hardness and toughness than a “high” temper of 1000°F.

2. Cryo led to an increase in hardness with little or no change to toughness. Increased cryo time beyond 1hr did not affect the properties.

3. The powder metallurgy versions, Z-Wear and CPM-CruWear, have significantly better toughness than the conventional version, CruWear. This is due to the finer microstructure from powder metallurgy.

CruWear (ingot, not the CPM version)

Z-Wear (Powder Metallurgy)

4. When tempering at 400°F, there was no change in properties with more than 2 tempers:

New Z-Wear Testing

So the new test used a 1950°F austenitize for 30 minutes, plate quench, cryo in liquid nitrogen, and a double temper at 400°F for two hours each time. 9 coupons were produced and tested from each of the two manufacturers.

The USA version ended up 1 Rc harder but one ft-lb lower in toughness. I didn’t get any one-off low toughness coupons that would suggest that one version or the other has large carbides or inclusions leading to lower toughness. The standard deviation of the toughness of the European version was slightly higher, but that could just be random, plus higher toughness coupons tend to have a bigger spread than low toughness coupons, so I wouldn’t read anything into that. To determine the reason for the higher hardness of the USA version I measured the composition of the two using OES (optical emission spectroscopy) along with combustion. Combustion tested carbon, sulfur, nitrogen, and oxygen. OES cannot test oxygen, and the carbon and sulfur values from combustion is somewhat better than OES, so both are presented in the table (listed as LECO C or LECO S at the bottom).

The LECO carbon values were a little lower than the OES, but both tests showed the USA version having higher carbon, which is probably the primary reason that steel came out with higher hardness. The P and S content were similar between the two, phosphorus a little lower in the USA version but sulfur a little lower in the European version. The oxygen content of the European version was similar to the Bohler and Uddeholm stainless steels I previously tested. However, somewhat surprisingly the oxygen content of the USA version was the lowest result I have yet had for any PM steel. Perhaps something about the composition of the stainless steels led to somewhat higher oxygen content such as the high chromium content. I am not sure if the USA oxygen content was so low in this case due to variability between heats of steel or some improvement to their process since my last test. Either way I think the results of both of these steels look good.

Because the hardness was different between the steels I wanted to compare against the previous Z-Wear results to see the “normalized” toughness for a given hardness. To see if 1 ft-lb toughness is as much improvement as we would expect based on roughly 1Rc lower hardness. So I plotted them all on the same chart:

The new USA material tests roughly fall on the same trendline as the previous Z-Wear testing, while the new European material falls a bit below the trendline. I believe this is likely due to the small composition differences, or perhaps a difference in annealing (resulting in a different response to the same heat treatment). I would consider these materials to be basically equivalent.

Summary and Conclusions

While there has been significant marketing from the European powder metallurgy companies that they have superior powder metallurgy technology, I have not found a difference when it comes to impact toughness testing. Whether other types of tests would reveal a difference I can’t say, but in general I think performance-wise the composition of the steel matters more than the company making the powder.

---

[1] Tornberg, C., and A. Fölzer. “New optimised manufacturing route for PM tool steels and High Speed Steels.” In Proceedings of the 6th International Tooling Conference: The Use of Tool Steels: Experience and Research, vol. 1, pp. 10-13. Karlstadt Sweden, 2002.

The post USA vs Europe – Powder Metallurgy Knife Steels appeared first on Knife Steel Nerds.

Thanks to the new Knife Steel Nerds Patreon supporters! The newly performed research in this article is all paid for through Patreon funds, such as the purchase of expensive Damasteel. Patreon money is only used for knife steel research. Sara Rempelos, Theo N, Christopher Kuehl, Dirk Hoogenbosch, Nick, nats spawnee, Krisztián Szegi, Todd Ellner, Seth V, Jonathan Graham, Ben Secrist, Drew Certain, Scott Armstuts, Ronald Justin Agee, Jim Darnall, Chris G, Farrell K., Bill Behnke, Paige, Luis Hernandez, clockworkfish, Barry Gordon, KarRawr, Ming Lin, Theodore Loach, Matt Bobchin, Flo, J.T. Pouland, Mark Watt, 愷麒 王, and Nickolay Matershev.

Video

Here is the video version of the following information:

Damasteel History

Damasteel was developed and patented by Pelle Billgren and Kay Embretsen [1]. At the time, Billgren worked for the steel company Erasteel in Sweden and he was looking for new uses of their powder metallurgy steel. He connected with bladesmith and Damascus steel maker Embretsen and they worked together to make what eventually was branded as Damasteel. The original material they patented was a combination of Elmax steel and 304L, but by the time it was advertised in the USA in 1996 it had their final combination of RWL34 and PMC27. Damasteel was unique in that it was two different powders which were layered up with no “solid” sheet component. RWL34 is the same composition as ATS34/154CM, and it the name is a tribute to Robert Waldorf “Bob” Loveless who famously introduced those steels to the knife industry. PMC27 is a powder metallurgy version of Sandvik’s 12C27. You can read more about the history of Damasteel, Kay Embretsen, Damascus steels, and knife steel in general in my new book The Story of Knife Steel: Innovators Behind Modern Damascus and Super Steels. Around 2016, the RWL34/PMC27 combination was renamed DS93X. They also have low carbon austenitic stainless products for non-knife applications, and “san-mai” products with a core steel called Damacore. I previously wrote about Damacore in this article. The rest of this article focuses on the DS93X product with RWL34 and PMC27.

Composition and Microstructure

As shown on the chart, the two steels, RWL34 and PMC27, are very similar to their inspirations, ATS34 and 12C27. I get mixed information on whether 154CM or CPM-154 have a small vanadium addition, it has a very limited effect on properties, as there is so much chromium carbide in RWL34 that those act to keep the grain size small. The high chromium content also prevents significant content of vanadium carbides from forming; instead, the vanadium is found in the chromium carbides. There also are no molybdenum carbides to be found (Mo2C or Mo6C). Instead the molybdenum is found in the chromium carbides (M7C3 or M23C6, where M can be chromium, molybdenum, etc.).

RWL34 is the “bright” layer and PMC27 is the “dark” layer in the micrograph above. Because Damasteel is constructured with layering of powder, there can be somewhat diffuse transitions between the two steels, which on a small scale are not as sharp as in pattern-welded Damascus made with solid sheet steels. This does not appear to have any deleterious effect on the “macro” pattern observed in the final material.

12C27 has a very find microstructure without powder metallurgy due to careful composition design and processing. You can read more about how those steels were designed in this article on AEB-L. With powder metallurgy, the PMC27 remains very fine with very small carbides (the bottom material in the micrograph above). RWL34 has much more carbide than PMC27 (roughly 16 vs 4%) with its higher carbon and alloy content but the carbides remain relatively fine due to the powder metallurgy process. You can compare with the microstructure of many other knife steels in this article with many micrographs.

Heat Treatment

There are a surprising number of things to talk about with Damasteel heat treatment, and I have gotten quite a few questions about the datasheet. Until recently the (old) datasheet recommended an 8 minute hold time for 3.2 mm (1/8″), with an increase or decrease of one minute per 0.5 mm. However, a new datasheet was released this year (2023) which recommends a 15 minute hold time instead. The 15 minute hold is more in line with my recommendations.

Heat treatment instructions from the current Damasteel datasheet.

Adjusting by the minute based on thickness makes sense when using a conveyer belt furnace, but for conventional furnaces this is riding the line too close where different sizes of knives (even at the same thickness) can affect the time for the steel to heat up to temperature. Some knifemakers have tried to ride this line in hopes of a finer grain size; however, grain size is much more greatly controlled by temperature than by time. Instead it is more important that the steel sees enough time, to ensure that carbides are dissolved, sufficient carbon is in solution for hardness, and sufficient chromium is in solution for corrosion resistance. The danger of an insufficient soak is much worse, leading to poor hardness, toughness, and corrosion resistance. While the chances of an overly long soak time are quite low. The changes to the steel in terms of transformation and carbides dissolving will “level off” after a certain amount of time and then changes are very slow after that. So I recommend that the soak is “long enough” rather than trying to make it as short as possible.

Example of change in carbon and chromium in solution with austenitizing time for 52100. With short soak times the changes are great, while after sufficient soaking the behavior is more flat.

Another change between the old and new datasheet is the cold treatment recommendation. The old datasheet said to use a cold treatment for heat treatments IV and V, while the new datasheet does not include this instruction, and says only that “deep freezing is not necessary but completes the martensite transformation and increases hardness.” I do not recommend skipping a cold treatment when using the 1080°C/1975°F austenitze, for reasons I will explain shortly. I recommend sticking to 1050°C/1925°F if only quenching to room temperature.

Hardness values are listed for RWL34 and PMC27 for each of the five heat treatment conditions but it does not specify whether this assumes a cold treatment or a room temperature quench. Whether the cold treatment is included has a strong effect on these final values. Another interesting aspect is that rather than giving a final hardness for the “DS93X” Damasteel combination of the two steels, instead it gives hardness values separately for RWL34 and PMC27, presumably so that the knifemaker can select a heat treatment that works for both alloys. Also the PMC27 look rather low when compared with the data on 12C27 from Sandvik [2][3] as shown on the chart I created below. The RWL34 values are much more in line with reported heat treatment data from Hitachi ATS-34, Latrobe 14-4CrMo, and my own experiments with CPM-154.

Tempering chart for Damasteel from their datasheet.

Comparison of Sandvik 12C27 and Damasteel PMC27 heat treatment data.

In my heat treatment experiments I used the same 15 minute austenitize specified in the current datasheet, a plate quench, and tested either with a room temperature quench (no cryo), or a dip in liquid nitrogen (cryo). Rockwell hardness is affected by both steels, and would not only reflect the harder of the two steels. However, when comparing the resulting “composite” hardness of the Damasteel product, the values are basically the same as RWL34 cryo heat treatments and are not similar to PMC27. For example, in a combination of ~62 Rc 1095 and very soft nickel (approximately 8%), the composite hardness value was only ~51.5 Rc. You can read more in the previous article I wrote on experiments of many Damascus steels.

Note also that the hardness drops without cryo above 1925°F, which is why I recommend limiting the austenitize to 1925°F when cryo is not available. This is in line with other heat treatment data from Hitachi and Latrobe on ATS-34, as shown below. When “overaustenitizing,” the hardness drops from excessive retained austenite. Cryo can transform some or all of this retained austenite so that hardness will climb with even higher austenitizing temperatures. Excess retained austenite, even if the final hardness is acceptable (ie 60 Rc), will lead to poor performance, as the retained austenite is very soft and will lead to deformation at lower stresses than would be seen at the same hardness without the retained austenite. The steel will deform as if it is at a significantly lower hardness. You can read more in this article on cryo.

So why does the steel heat treat like RWL34 if roughly half of the steel is PMC27? The reason is because the two steels do not behave the same as when the two are heat treated separately. When combining two steels in Damascus, contrast is achieved after etching because the alloy contents are different, in this case the biggest difference is in the 4% Mo in the RWL34 which makes that steel resist etching better than the PMC27 which creates the bright layer. However, carbon is a very small “interstitial” element (between the iron atoms), which means it diffuses very rapidly. During the forge welding and forging process the carbon equalizes between the two steels, changing the heat treatment behavior of the two steels. It is slightly more complicated than this because some carbide will still be present in the CPM-154 even at a high forging temperatures such as 2150°F. So the carbon that will equalize will be the carbon “in solution” for the two steels at the forge welding and forging temperature. Using ThermoCalc for that temperature I estimate that RWL34 loses about 0.1% carbon while PMC27 gains about the same amount, resulting in the RWL34 having 0.95% carbon and PMC27 having 0.7% carbon. In this case, the resulting “carbon in solution” of the two steels during austenitizing ends up being very similar to the original RWL34, and thus the hardness values of PMC27 on its own are basically irrelevant to the heat treatment. This would make the PMC27 roughly the same composition as AEB-L, which also has its peak austenitizing temperature at 1925°F without cryo and 1975-2000°F with cryo (see this article). Instead it would be better if the datasheet just showed the resulting hardness data for heat treating the “DS93X” combination of the two steels. Below I have shown a heat treatment summary from my own experiments:

So with 1/8″ material, a 15 minute austenitize works well, thicker material may necessitate longer hold times. Using 1900-1925°F is good if not using cryo, with cryo you can austenitize as high as about 2000°F for higher hardness. Temper to desired hardness.

Edge Retention

The edge retention of Damasteel compared with other Damascus patterns was previously shown in this article on Damascus performance. The Damasteel did very well, comparable to “mid-tier” wear resistance steels such as CPM-3V or CPM-154. We used a heat treatment of 1950°F for 15 minutes, plate quench, liquid nitrogen cryo, and temper at 400°F. Read more about CATRA edge retention testing in this article.

High alloy Damascus combinations tested for edge retention with CATRA

A giant chart of other steels to compare against

The edge retention was tested with the “Hugin” pattern which is essentially a “ladder” pattern which puts a wave into the steel. We found ladder patterned Damascus to have better edge retention than “random” straight layers as shown on the ApexUltra/L6 chart.

Damasteel “Hugin” pattern CATRA coupon

The wavy appearance created in the “edge” of a ladder pattern bar (this is not Damasteel)

ApexUltra/L6 Damascus showed better edge retention with a ladder pattern

However, you will notice that the layers of the Hugin pattern flatten out as they approach the edge, which is not because the patterning doesn’t reach the center of the bar, but rather because of the shape of the initial billet which are layered with powder prior to forging flat (notice how the layers also flatten out as they approach the spine of the test knife). This results in layers parallel to the edges while looking more typical of layered steel in the center. Thus we were somewhat surprised that the edge retention was identical to the ladder patterned steel we tested of AEB-L/154CM, which are nearly identical steels. Could the Damasteel have even better edge retention if the layers “crisscrossed” the edge like traditional pattern-welded Damascus? To test this we made a new coupon using a “dense twist” pattern which does have layers crossing the edge with a higher density.

Damasteel “dense twist” CATRA coupon

Damasteel “dense twist” cross-section

However, when I tested the dense twist the result was largely the same as Hugin. If there was a true increase in performance it is very small. In either case, the edge retention of the Damasteel is very close to CPM-154 (the same as RWL34), despite the presence of a large amount of PMC27 with much less wear resistance (similar to AEB-L on the chart below). Therefore the ladder patterning leads to a significant boost in edge retention.

Thus it appears that the effect of the layers is minimal, and most of the effect comes from the change in shape of the microstructure instead. There is still directionality to the microstructure, especially carbide banding, which would have its shape changed through the ladder patterning. Below is an image of carbide banding:

Carbide banding in high speed steel (rolling direction is vertical) [4]

This carbide banding theory could be confirmed by testing CATRA edge retention of a single steel which was given ladder patterning. We effectively did this test already with the 3125 layer AEB-L/154CM where layers were no longer visible. We also tested layer counts of 25, 125, and 625. However, regardless of the layer count the edge retention was the same, as shown in the chart below:

The reason the layers are not visible is not simply because the layers got so thin they cannot be viewed. When the layers become thin enough, the larger alloying elements (not only carbon) will equalize between the steel leading to a roughly consistent composition throughout the steel in terms of molybdenum and chromium. No pattern was apparent in the 3125 layer steel.

3125 layer AEB-L/154CM steel with no apparent layers.

Toughness

I also tested the toughness of the Hugin pattern Damasteel with two heat treatments:

1. 1950°F for 15 minutes, plate quench, liquid nitrogen cryo, 400°F temper (~61 Rc)
2. 1975°F for 15 minutes, plate quench, liquid nitrogen cryo, 300°F temper (~64.0 Rc)

The toughness of Damasteel was close to the RWL34 on its own, with only a small boost due to the tougher PMC27 (compare with AEB-L on the chart). This was similar to other Damascus steels that we tested, where toughness was largely controlled by the “less tough” of the two steels. In our initial tests of the dense twist patter, we got a surprising amount of variability when compared with the Hugin pattern:

Because of this unexpected behavior, I made four more coupons and retested, and this time the behavior was more consistent. The average toughness did not change that much, however. It appears that when compensated for hardness the toughness was roughly the same between the dense twist and the Hugin pattern.

Summary and Conclusions

Damasteel DS93X is a high quality powder metallurgy stainless Damascus. It showed good toughness and edge retention in our testing. There are a couple issues with the datasheet and I have slightly different recommendations for heat treating, but their most recent datasheet did change their austenitizing time recommendation in what I think is a positive change. For 1/8″ material and thinner I recommend a 15 minute austenitize from 1900-2000°F (1035-1095°C), with a max of 1925°F (1050°C) if not using cryo after the quench. Temper to desired hardness with a minimum of 300°F/150°C. I didn’t test tempering temperatures higher than 400°F to see when tempered martensite embrittlement happens. Generally a 350-400°F (175-205°C) temper gives more balanced properties than maxing out the hardness with 300°F/150°C.

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[1] Billgren, Per, and Kaj Embretsen. “Method relating to the manufacturing of a composite metal product.” U.S. Patent 5,815,790, issued September 29, 1998.

[2] https://www.alleima.com/en/products/strip-steel/strip-products/knife-steel/hardening-guide/hardening-programs/alleima-12c27-batch-hardening/

[3] https://www.alleima.com/en/products/strip-steel/strip-products/knife-steel/hardening-guide/hardening-programs/alleima-12c27-batch-hardening-deep-freezing-70c-95f/

[4] Mesquita, Rafael Agnelli, and Celso Antonio Barbosa. “High-speed steels produced by conventional casting, spray forming and powder metallurgy.” In Materials science forum, vol. 498, pp. 244-250. Trans Tech Publications Ltd, 2005.

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