Pros and cons of composite steel blades

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DangerZone98

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Dec 7, 2019
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Greetings. My apologies if this has been asked before. What do you guys think about composite blades such as the one on the Kershaw Dividend? What does a composite steel blade offer that gives it an edge over a regular ole S35VN blade? Gimmick or legitimate?

Admittedly, I know next to nothing about composite steel so this caught my attention.
 
co556guy said:
The monosteel m390 will blow the composites out of the water.

The composite blade is about the visuals, not performance.

Not a criticism really, just an observation.
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Mmm, I see. I’m coming from a point of ignorance, but does the composite characteristic make the blade weaker?
 
To my understanding, the goal is to put a steel with great edge holding capability along the edge, while using a more flexible steel for the majority along the back side and spine. It's intent is to try and get the best of both worlds... How it actually performs in real world application is up for debate, but the theory is you get a great edge holding steal, with overall improved lateral toughness of a softer steel... Obviously you still can't put the full lateral pressure allowed by the softer spine steel across the entire blade, because the harder edge side will still be affected by it's own limitations, but that's the theory as I understand it. Similar to a good hamon heat treat, where the edge is treated to a higher hardness for edge retention, and the spine side is treated to be left softer for better toughness, and the hamon line shows the separation in heat treated areas...
While that theory still holds true, Sometimes (oftentimes) it is also applied simply for cost effectiveness... I have a set of budget friendly Shun kitchen knives that are composite vg10 edges, with (much cheaper, but tougher) 420 spines. Theory does still apply, but the goal was also cost effective, as 420 is far cheaper then vg10, and 3/4 of the blade steel is 420, but the vg10 edge are far superior in edge holding then 420 would be...
...
And they look cool...
 
Laminated blades are nothing new. Mora has offered them as an option for over 100 years on the Number 1 and Number 2. (at a higher price than a plain carbon steel or stainless steel blade.)
I believe other Scandinavian Pukkoo makers offer laminated blades as well.
If a gimic, I think it would have died out long ago.
 
I think the composite blades from Kershaw are welded/ brazed together at that neat looking
geometric "hamon" where the two metals meet. The traditional "composite" blades most would think of are
forge-welded sandwich style in a technique called "san mai" or simply "laminated steel"
The Kershaw blades look like something all together new and different from the traditional laminating process.
I don't know enough about physics and metal to tell if you'd actually get the same benefits as traditional lamination, but
it would make sense if it's still a hard edge supported by softer, tougher steel.

If you haven't seen Kershaw's Dividend commercial....it's epic :D
I need one for my next Overland BMX Snowboarding AR-15 excursion.
Lots of little EDC tasks that might come up :cool:
 
Differential heat treating, laminated blades, the original, actual purpose of Damascus steel... the trade off between a blade that flexes and an edge harder than woodpecker lips. This is for the same, perennial purpose.

Not sure which is the best, cheapest, easiest to accomplish. I'll leave that for more knowledgable folks.
 
Don't quote me on this one, though, I remember that the composite blades couldn't actually reach the higher hardness for certain steels because the filler couldn't reach the required high austenitizing temps for those steels.

IIRC, the S110V portion of the composite blades were lower than ideal hardness. This could be explained that the filler material for the brazing is some form of copper. Copper has a melting point just a little lower than 2000F; S110V requires austenitizing temp of greater than 2000F (2150F per spec sheet). Well, you can see the issue.

It was either that or the temps required for brazing messed could have mess with the tempering if they combined the blades post HT. Though, again, there was a process required that would have changed the HT process for that particular main blade steel.

Definitely a cool proof of concept. However, like some folks mentioned here, a homogeneous high alloy PM steel with thin edge geometry and higher will perform better and the "need" for a more "durable" spine becomes nonexistent.

If you want a real "composite" steel that performs and looks nice, Damasteel could be your jam. It's PM damascus and the tech behind it is pretty cool. They even make a layered damascus with nearly a corrosionproof high nitrogen steel. Haven't seen too many makers use it, though.
 
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davek14 said:
Differential heat treating, laminated blades, the original, actual purpose of Damascus steel... the trade off between a blade that flexes and an edge harder than woodpecker lips. This is for the same, perennial purpose.

Not sure which is the best, cheapest, easiest to accomplish. I'll leave that for more knowledgable folks.
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The utility of composite blades has been reduced not because laminated blades all of a sudden became bad......

They have been usurped by steel quality of more advanced monosteels that provide good hardness and toughness. Doing a sanmai on a carbon steel like m4 would be interesting though, for corrosion resistance, for example. But for strength, m4 is likely actually stronger/tougher without the cladding (of equal total blade thickness).
 
To quote Marge Simpson: "I just think they're neat."

Obligatory photo, taken in my kitchen:

nsqqR7Y.jpg
 
co556guy said:
The monosteel m390 will blow the composites out of the water.

The composite blade is about the visuals, not performance.

Not a criticism really, just an observation.
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Are you sure about that ?
What about M390 for core and 416 SS from sides ?
What do you mean when you say performance ? Edge retention ?
Toughness ? Rust resistance ?
 
Natlek said:
Are you sure about that ?
What about M390 for core and 416 SS from sides ?
What do you mean when you say performance ? Edge retention ?
Toughness ? Rust resistance ?
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I agree; wrapping a hard but not corrosion resistant or tough core with an outer layer that is tougher and more corrosion resistant clearly has some advantages.
 
evilgreg said:
I agree; wrapping a hard but not corrosion resistant or tough core with an outer layer that is tougher and more corrosion resistant clearly has some advantages.
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Of course that has some advantage .This is my first san mai knife i make .Core is 1 - 1,2mm 1.2519 carbon steel and 64 hrc , for cladding I used 304 or 416 was it i don t remember now.Total thickness was 3.5mm .And I can bet in whatever someone want that this san mai blade is more tough than blade in same thickness from 1.2519 steel in same hardness . And both have edge retention same ..............
Pure Maxamet steel on 70 Hrc is like glass , san mai Maxamet ??
bpojNiU.jpg
 
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Natlek said:
Are you sure about that ?
What about M390 for core and 416 SS from sides ?
What do you mean when you say performance ? Edge retention ?
Toughness ? Rust resistance ?
Click to expand...

If you read my following post, i account for the benefits of sanmai for corrosion resistance, using m4 as an example.

My point is that in the past, laminated/damascus was a way to deal with issues of steel not of the qualities of more modern steel formulations.

I doubt that using a soft, less tough steel as cladding such as sanmai would do anything to improve on the toughness of a steel that's superior in that way.

If you use a cross section of a blade, let's say ffg delica because its commonly known.

Do you think a solid m4 blade will be more or less tough than a m4 blade with a softer stainless cladding (which would necessitate a thinner section of m4 than the solid m4 blade?

Is the stainless cladding in this example doing anything besides preventing oxidization? Is the loss of m4 steel helping or hurting toughness? Since m4 is consdered quite tough, I am of the opinion that logically the solid m4 blade will be tougher, all other variables being equal.....as a result of there being more steel of the tougher material.

With less tough steel, you might find a different outcome. Or brittle steels cladded in more tough steels. Cladding could help keep the very hard yet brittle steel from dealing with stresses as much as a monosteel blade.

At the end of the day, with the steel available today.....it would produce a better knife to use a better monosteel choice than to try to overcome inherent deficiencies in less-optimal steel by using sanmai/damascus/etc.

Does anyone sanmai 3v? I'm pretty sure nathan carothers would sanmai it if it made his knives better. Does anyone sanmai 4v? M4? K390? I can't say I've run across any.

SO, my claim in tl;dr terms is: selecting a better monosteel will provide better performance outcomes (whatever that metric is as long as it's not "visual enjoyment) than using a laminated/damascus process while avoiding the issues inherent to the welding of two different steels.
 
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Laminated/San Mai blades seem to be a good idea on paper. I don't believe I've ever seen any tests with modern steels to really determine if there is a difference in reality. This would be an interesting test to read about.

Downsides? Besides potential cost, I don't like the appearance of a laminated blade with carbon steel core and stainless steel cladding, I prefer that the different materials patina at similar rates.

Now thinking from an engineering standpoint, it seems that the biggest advantage would be to limit potential fracture if you want the edge to be a steel with poor notch resistance. I don't know what steels those might be but Maxamet might be one. OTOH a blade with softer cladding would deform more readily in bending than a blade with hard steel that has good notch resistance. This is simply strength of materials analysis.
 
I thought that composite blades had little to do with laminated blades. My Kershaw Tyrade has CPM-D2 edge and a 154CM backing. They don't say how hard the D2 is. I think it's a cosmetic thing like Damascus.View attachment 1516077
 
Knives like these are just an opportunity for a knife maker to show their skills. Of course knife nuts love them due to the magpie gene.

The San Mai or hard blades clad with a soft steel are in a different category. Still desirable though.

If we all just got the most practical and efficient knife and called it a day this would be a pretty boring place.
 
bdmicarta said:
Now thinking from an engineering standpoint, it seems that the biggest advantage would be to limit potential fracture if you want the edge to be a steel with poor notch resistance. I don't know what steels those might be but Maxamet might be one. OTOH a blade with softer cladding would deform more readily in bending than a blade with hard steel that has good notch resistance. This is simply strength of materials analysis.
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That and saving money . Why you should use 3mm thick Maxamet / with poor toughness/ when you can clad 1 mm Maxamet with some tough steel ?
This is my chopper and recently completed Nakiri .......hard steel is just under that line , rest is soft with very low carbon steel.

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