laminated steel related questions

[chippermonky]

Hi, (currently) hobbyist woodworker / toolmaker. I especially love Japanese woodworking tools and by extension Japanese knives.

I'm interested in making my own tools and knives. Sure I'd love to learn how to forge but also that's another hobby I don't need so I'm hoping to stick to just stock removal. I've also recently come to learn all the wonderful details around modern steels.

I had a couple questions I couldn't quite find answers too. Hoping folks might fill me in:

1. Is there a source I can find single side laminated steel blanks for making single bevel knives and woodworking tools (most of which are single bevel)? Mostly interested in just buying a few pieces for small one-off projects but eventually I may want to buy a whole bunch for production.
2. Is there a source where I can find laminted PM steels, like magnacut or CPM-10v.
3. Why are laminated PM steels not more common? It seems like a win-win-win. Less use of the super expensive metal, better toughness from softer cladding, easier to sharpen. I hear folks talk about monosteel like it's a good thing.
4. Is there a guidance around thickness for laminated hard steel? On Japanese woodworking tools I've always noticed the hagane (hard steel) part can be quite thick and I never quite understood why.
5. Can you forge laminate powder metal (PM) steels? That seems to be how people do it? Does the heat not dissolve away all the tiny PM carbides? Because my understanding (from knifesteelnerd) is that normalizing is to dissolve carbides so that they can reform more evenly and forging will go well above normalizing temps.

 

[esoo]

Why are laminated PM steels not more common? It seems like a win-win-win. Less use of the super expensive metal, better toughness from softer cladding, easier to sharpen. I hear folks talk about monosteel like it's a good thing.

I'll address this one as I had a discussion recently with a maker it and I prefer monosteel knives.

Cladding sucks. It either rusts faster than the core (for carbon) or it scratches way too easily (for stainless).

Cladding doesn't change how tough the edge is going to be - that is determined by the core steel.

Cladding doesn't help sharpening. It helps thinning. It also will help in straightening the blade.

Yes, cladding helps reduce material usage of the core steel. But I don't care about that - that's a maker thing, and I'm a user.

 

[blokey]

Cladding line can be beautiful tho

 

[Jovidah]

There's plenty of laminated PM steels, but I guess it's more of a Japanese thing? My gripe with Japanese PM steels is that you see them almost exclusively in san-mai version.

As to san-mai versus laminated:
-Everything esoo said, he covers the most important points; it's mostly easier and cheaper for the maker; steel cost is lower (though that's probably not a huge factor these days), but most of all grinding is easier and that means less time cost and less abrasive cost.
-Sanmai is easier to bend/straighten (again mostly useful to the maker).
-The cutting feedback is different... which one you prefer is really personal preference but for me it's mono.
-Not everyone is a fan of cladding (monosteel carbon is far less reactive than iron-clad, stainless clad feels like wrapping your knife in a plastic bag).

In general I think san-mai is still a hold-over from the past where iron was scarce and it was worth a lot of extra time and effort to stretch quality steel with lesser steel. These days the cost of good steel is a lot smaller, and especially a much smaller fraction of the end product.

 

[MSicardCutlery]

1. Is there a source I can find single side laminated steel blanks for making single bevel knives and woodworking tools (most of which are single bevel)? Mostly interested in just buying a few pieces for small one-off projects but eventually I may want to buy a whole bunch for production.
2. Is there a source where I can find laminted PM steels, like magnacut or CPM-10v.
3. Why are laminated PM steels not more common? It seems like a win-win-win. Less use of the super expensive metal, better toughness from softer cladding, easier to sharpen. I hear folks talk about monosteel like it's a good thing.
4. Is there a guidance around thickness for laminated hard steel? On Japanese woodworking tools I've always noticed the hagane (hard steel) part can be quite thick and I never quite understood why.
5. Can you forge laminate powder metal (PM) steels? That seems to be how people do it? Does the heat not dissolve away all the tiny PM carbides? Because my understanding (from knifesteelnerd) is that normalizing is to dissolve carbides so that they can reform more evenly and forging will go well above normalizing temps.

This is sort of a deep rabbit hole but I'll try to answer these as simply and directly as possible.

1: Not likely a commercial one, no.

2: Probably not but there are some places that do make them in small quantities.

3: A: They're more difficult to weld, forge and have very tight forging parameters. B: the expense saved by using a cladding will likely never exceed the expense incurred by the cladding process except on an industrial scale or with the very highest wear resistance steels (on grinding belts and so on)

4: Not as far as I know of. Without a nickel layer there will be carbon diffusion, so having too thin a core can mean that the core has lost enough carbon to have diminished properties compared to a monosteel blade, so that might be a consideration.

5: A: Yes, I've done it with a few different ones in the context of san-mai (Zwear, MagnaCut, S90V, and M4). B: PM/high alloy steels are a different animal than low alloy steels. They don't get normalized after forging, (if they get forged at all), they just get annealed, and most of them have carbides that would remain undissolved up to the melting point of the steel. And in the PM steels carbide distribution is about as good as it's going to get. Forging is unlikely to improve the properties of them at all. There was some observable change in conventionally made 154CM from forging, in the context of damascus steel (see Larrin's recent article on damascus steel testing), but it was not significant.

Also, I've had a few failed billets in PM steels that separated to essentially become ni-mai. I'm pretty sure I have 1 each in Z-Wear and S90V, maybe 2 in one of those steels. DM me.

-Matt

 

[esoo]

Cladding line can be beautiful tho

It can be. And cladding can create a beautiful kasumi finish.

But in the long term, as I use my knives all that goes away when I leave a knife wet on the board and eat dinner.

 

[chippermonky]

Thanks for the detailed responses everyone! Very helpful information.

 

[chippermonky]

There currently only a handful of tool makers making PM steel tools and only zen-wu makes them laminated (they use their own steel but it seems to perform on par with other PM steels)

With woodworking tools, you need to sharpen them frequently so good edge retention and ease of sharpening tend to be more important.

One more question I forgot to add. I heard a few times in many places when talking about woodworking tools that the high alloy steels don't take as "fine of an edge". So blue steel is used for wear resistance but you would prefer a pure carbon steel like white #1 to get a fine edge. Does anyone know why this is? Do folks care about this in cutlery? At my current skill level in woodworking/sharpening (which I do freehand), I haven't noticed a difference albeit I haven't really tried either.

Someone at a woodworking forum did a few tests and it showed the W1 chisel outperforming (subjectively) other PM steels in end grain shaving right after sharpening https://www.inthewoodshop.com/ToolReviews/ChiselParing.html (it didn't fair so well in edge retention)

 

[Jovidah]

Someone more qualified me can probably make a better explanation than me, but I'll give you the amateur version first:

It's a theoretical thing that can occur if you have carbides that are harder than your sharpening stones (so for example having a fancy steel loaded with vanadium carbides that you're trying to abrade with a softer aluminium oxide stone).
If you have an abrasive that can properly abrade the carbides like diamonds it shouldn't be a problem, though there's still the potential issue of carbide popout.

It does get mentioned and talked about here, and for example in high end-single bevel fish slicing it might even make a noticable difference (and this is why most single bevel yanagibas are in white steel), but for general kitchen use hammering away with a gyuto I don't think it's something that really plays a big role after the first few chops.

If you really want to get into the nitty gritty of these kind of things you should spend some time on Larrin Thomas's blog: Knife Steel Nerds - Metallurgy and Testing of Knives and Steel
Short of getting a degree in metallurgy or reading a bunch of dedicated books on the subject I don't think you're going to find a better source. He's even a member here!

 

[esoo]

Edge retention is a complicated subject as it depends in part on personal preference. For many, they like the fresh off the stones feeling of a sharp blade from a White steel, but that edge will last only so long. On the other hand, many here dislike VG-10 as it is tough to get that super sharp edge and loses it quickly, but will remain functionally sharp much longer than other steels. In a certain use case, each steel would have a certain degradation - how long till it loses the fresh feeling, how it long it lasts until you consider it not sharp, and how it goes from sharp to dull (does it stay sharp and then drop off a cliff, or does it slowly dull over that time). And those characteristics would change depending on the product - cutting onions vs tomatoes vs lemons.

The other item affecting edge retention desires is the user. For the average home user, edge retention is a meaningless topic - it can be measured in day/weeks/months. For the pro user however, who can cut more in a shift than a home user in a year, retention is something different. Ideally for them, a edge needs to stay sharp to their desires for at least 1 shift. In the middle of service, they don't want to deal with a dull knife. @stringer has had some good threads about knife use in a pro kitchen - IIRC his day could start at 50# of onions and go on from there.

Fineness of the edge on a kitchen knife again comes down to the user, the technique and the product they are cutting. Certain techniques excel with certain edges. For general work, I would say the saying "refined yet toothy" seems to be a good starting point. Super fine edges (like the kind you get from high grit stones on simple carbon), tend to work better on slicing type work like sushi. This is a specialized edge where there is little board contact so again edge retention gets measured differently. As well, sushi chefs working with carbon also tend to have a requirement to keep their blades looking pristine (no patina) so working on their blades is a daily part of the job.

It's complicated by the fact that no one knife does it all. A rock chopping chef using a gyuto prepping a mirepoix on a poly board vs a chef tap chopping tofu with a chuka bocho on a wood grain board vs a sushi chef slicing sashimi on a rubber board all have different requirements for edges and steel.

 

[Troopah_Knives]

@chippermonky I just wanted to clear something up because there has been some mixing of terms in this thread.

PM steels are simply steels made using the Powder Metallurgy method which leads to very fine carbides due to fast solidification times. They don't have inherent properties like high wear resistance or poor grindability. Those are all determined by the exact alloy composition. In fact, for a given alloy a PM production of the steel will lead to better grind ability due to its finer carbides. The conflation of PM and high wear resistance comes from the fact that many steels with high V, and Nb contents need to be produced through PM in order to have acceptable toughness. There are plenty of PM steels that can be sharpened with conventional abrasives like CPM 154 and CPM-D2.

High alloy steels can generally be described as steels with >3.5% Cr content. This Cr addition makes it difficult (but not impossible) to laminate/forge weld due to the formation of oxides on the surface of the steel when exposed to air. There are quite a few high-alloy steels that are made into laminates and used.

MC carbide steels are steels with either 1. low Cr and significant additions of W (and sometimes Mo) or 2. significant additions of V or Nb. These steels form extremely hard MC-type carbides which can present issues during sharpening as the carbide is harder than conventional abrasives. The amount of MC carbide is usually a good predictor of the extent of the problem but size also plays a role. These steels can be conventionally produced, like Apex Ultra and M2, or produced through PM methods like CPM MagnaCut and CPM 10V.

As a whole there are very few high alloy steel laminates produced, the most common ones you see are things like SG2 and D2 laminates, both very well-established alloys used at large scales. I would suspect the reason you don't see other laminates very often is due to the relatively low demand for these steels in the first place and the difficulty in making them preventing their production at a smaller scale.

 

[chippermonky]

Thanks for the info and clarification Troopah. I've definitely been conflating the two. Lee Valley uses PMV-11 for their tools which is suppose to be very easy to sharpen.

 

[Troopah_Knives]

Thanks for the info and clarification Troopah. I've definitely been conflating the two. Lee Valley uses PMV-11 for their tools which is suppose to be very easy to sharpen.

hmm. I should pick up some for micrographs. I haven't seen anyone else image it.

 

[blokey]

I know this kind of graph are usually very exaggerated but damn it looks good, interested to see what kind steel is it
https://www.leevalley.com/en-us/discover/woodworking/2020/september/the-pm-v11-story

 

[Troopah_Knives]

I know this kind of graph are usually very exaggerated but damn it looks good, interested to see what kind steel is it
https://www.leevalley.com/en-us/discover/woodworking/2020/september/the-pm-v11-story

I have no idea what it is but that graph seems optimistic. For the low cost of 16.50+ shipping, we can find out.

 

[blokey]

I have no idea what it is but that graph seems optimistic. For the low cost of 16.50+ shipping, we can find out.

Would love to hear your find!

 

[JustAnotherJoe]

I have no idea what it is but that graph seems optimistic. For the low cost of 16.50+ shipping, we can find out.

So... I may have shot a sample with an XRF analyser already....
This model can't detect elements lighter than magnesium, so the carbon content remains a mystery.

Edit: ignore the "cronidur3". That's just what the gun thinks it is.

 

[Barmoley]

From this it looks like 440C or slight modification of it not exactly a revolutionary steel or even close to anything like M4. Let's see what @Troopah_Knives comes up with.

 

[JustAnotherJoe]

Whoa there buddy, this is definetly not an old school stainless. There is enough carbon in it to reduce the dissolved chromium to sub stainless levels and it can reach much higher hardnesses. There probably wouldn't be a reason to PM 440C, as it doesn't suffer from huge carbide formation reducing toughness.

Wood working tools are a bit of a desert when it comes to quality steels. The vast majority of tools are just really crummy heat treats of O1 and A2. Its already revolutionary in that they gave a damn long enough to do some testing and QC.

I hope I'm not comming off as rude or combative.

 

[blokey]

Whoa there buddy, this is definetly not an old school stainless. There is enough carbon in it to reduce the dissolved chromium to sub stainless levels and it can reach much higher hardnesses. There probably wouldn't be a reason to PM 440C, as it doesn't suffer from huge carbide formation reducing toughness.

Wood working tools are a bit of a desert when it comes to quality steels. The vast majority of tools are just really crummy heat treats of O1 and A2. Its already revolutionary in that they gave a damn long enough to do some testing and QC.

I hope I'm not comming off as rude or combative.

Interesting, can't figure out the carbon content since the variation between alloy percentage is bit large, looking forward to see what Troopha finds. I saw some of those Tungsten heavy high speed steel tool before, would them be too coarse to work with?

 

[Barmoley]

Whoa there buddy, this is definetly not an old school stainless. There is enough carbon in it to reduce the dissolved chromium to sub stainless levels and it can reach much higher hardnesses. There probably wouldn't be a reason to PM 440C, as it doesn't suffer from huge carbide formation reducing toughness.

Wood working tools are a bit of a desert when it comes to quality steels. The vast majority of tools are just really crummy heat treats of O1 and A2. Its already revolutionary in that they gave a damn long enough to do some testing and QC.

I hope I'm not comming off as rude or combative.

You are, but that is ok all good. I am guessing based on what was posted and the general accuracy of these guns with small amounts of elements. @Troopah_Knives already corrected me, but I will let him chime in.

 

[TB_London]

PMV is supposedly cpm154 with a rebrand

 

[Troopah_Knives]

Whoa there buddy, this is definetly not an old school stainless. There is enough carbon in it to reduce the dissolved chromium to sub stainless levels and it can reach much higher hardnesses. There probably wouldn't be a reason to PM 440C, as it doesn't suffer from huge carbide formation reducing toughness.

Wood working tools are a bit of a desert when it comes to quality steels. The vast majority of tools are just really crummy heat treats of O1 and A2. Its already revolutionary in that they gave a damn long enough to do some testing and QC.

I hope I'm not comming off as rude or combative.

I agree that it's probably not 440C. I have a good guess at what steel it is but I want to do my own testing to confirm first.

There is definitely a reason to make PM 440C as it forms very large primary carbides which can be greatly refined through PM

PMV is supposedly cpm154 with a rebrand

The above composition seems to preclude that as the Cr is too high and Mo is too low. I'm fairly certain its not a stainless steel.

 

[JustAnotherJoe]

There probably wouldn't be a reason to PM 440C, as it doesn't suffer from huge carbide formation reducing toughness.

You know, I think this is what "foot in mouth" looks like. My apoligies, I probably should have looked up a micrograph.

The accuracy of these hand held XRF guns are really dependent on the material your working with. As you can see those 3 sigma values can be pretty big for low alloy additions. They also have a tendency to thow out some BS readings, like I sincerely dout there is any nickle in or on that steel, but damn are they amazing!

The only laminated plane blades for western planes I know of are vintage or the ones that workshop heaven sold.

 

[blokey]

Any update on this？

 

[Troopah_Knives]

Any update on this？

I have the steel. Will do the analysis in early 2024. I've got to finish up testing for the 2053 and 9V articles.

 

[blokey]

I have the steel. Will do the analysis in early 2024. I've got to finish up testing for the 2053 and 9V articles.

Thank you for doing all this for us!

 

[Troopah_Knives]

Hey folks, I haven't forgotten about this. I have the sample and micrographed it but I haven't shared anything because my results make zero sense.

 

[jedy617]

Hey folks, I haven't forgotten about this. I have the sample and micrographed it but I haven't shared anything because my results make zero sense.

I forgot, did you get any strix or sg3 to test? Really curious about those

 

[Troopah_Knives]

I forgot, did you get any strix or sg3 to test? Really curious about those

nope. I'm hoarding Patreon funds. If you see a cheap knife with it give me a ring.