Visualizing the Tradeoff of Higher Hardness

[Steeltoez83]

I'd like to see s60v get a redemption run. I've only used Shawn's heat treat with s60v so I've been spoiled in that regard.

[electro-static]

I'd like to see s60v get a redemption run. I've only used Shawn's heat treat with s60v so I've been spoiled in that regard.

That would be interesting.

[Traditional.Sharpening]

I’d much rather have toughness than edge retention personally. A rolled edge is annoying but easier for a beginner sharpener to fix than a chip

It's not only easier for a beginner to fix a roll than a chip, this is true in almost all cases. In general, if you don't mind using very heavy duty edge geometry (over 15 DPS) and/or limiting to scope of work then this will be offset to a large degree. I do not consider 15 DPS to be an edge that I would choose to use on purpose for most knives so it directly influences the types of steels I like as many of the common steels here are not ideal at lower angles than 15 DPS. BD1N, LC200N, AEB-L, etc., all are an upgrade to me over most any high carbide steel for this reason. There are no better steels, only better suited steels for a given application of knife design and use.

[Synov]

Not sure how I missed this topic and charts back in February. In any case, better late than never.

I hope that you do not mind that I snagged the images.

10V at 61 to 62 HRC seems to be the most balanced high edge retention steel. I'd be satisfied with it in a Spyderco Native Chief for self defense. I do not think it is going to snap and it will definitely stay sharp for whatever needs must be met.

I don't mind at all. Just remember that this chart only shows a limited selection of steel for which sufficient data is available. It's more about showing the trendlines than it is about choosing steels. Here's an early draft where I sketched the data onto Larrin's graph and added labels for most of the steels:



Yes, 10V at 61 is a nicely balanced steel, with similar toughness to very popular knife steels but much more edge retention.

[RugerNurse]

I’d much rather have toughness than edge retention personally. A rolled edge is annoying but easier for a beginner sharpener to fix than a chip

It's not only easier for a beginner to fix a roll than a chip, this is true in almost all cases. In general, if you don't mind using very heavy duty edge geometry (over 15 DPS) and/or limiting to scope of work then this will be offset to a large degree. I do not consider 15 DPS to be an edge that I would choose to use on purpose for most knives so it directly influences the types of steels I like as many of the common steels here are not ideal at lower angles than 15 DPS. BD1N, LC200N, AEB-L, etc., all are an upgrade to me over most any high carbide steel for this reason. There are no better steels, only better suited steels for a given application of knife design and use.

The only knife I have a 15° per side is my VG10 Delica. But it’s used for light stuff. I think my LC200N is set to 17°. Why do high carbide steels break?

[Steeltoez83]

I've tested Bd1n on the polestar Gen 2 in terms of its wear resistance/toughness relationship. I have to agree with where Dr Larrin set his toughness value for Bd1n from the testing trialsI have personally done. To me Magnacut has one of the best blend of toughness and wear resistance relationships but I've yet to test a spyderco product with it.

[Synov]

The only knife I have a 15° per side is my VG10 Delica. But it’s used for light stuff. I think my LC200N is set to 17°. Why do high carbide steels break?

Large carbides are crack initiation points, like impurities in the steel. High density of small carbides allows already existing cracks to propagate easily. See the carbide section of this article for more detail: https://knifesteelnerds.com/2018/05/28/ ... -of-edges/

[RugerNurse]

I’ve never ventured into the high carbide steels. I might do K390 but that’s it. H2 would be plenty tough for my needs for outdoor stuff I think. Or LC200N

[weeping minora]

I’d much rather have toughness than edge retention personally. A rolled edge is annoying but easier for a beginner sharpener to fix than a chip

It's not only easier for a beginner to fix a roll than a chip, this is true in almost all cases. In general, if you don't mind using very heavy duty edge geometry (over 15 DPS) and/or limiting to scope of work then this will be offset to a large degree. I do not consider 15 DPS to be an edge that I would choose to use on purpose for most knives so it directly influences the types of steels I like as many of the common steels here are not ideal at lower angles than 15 DPS. BD1N, LC200N, AEB-L, etc., all are an upgrade to me over most any high carbide steel for this reason. There are no better steels, only better suited steels for a given application of knife design and use.

The only knife I have a 15° per side is my VG10 Delica. But it’s used for light stuff. I think my LC200N is set to 17°. Why do high carbide steels break?

In a nutshell: Carbide size, volume and distribution, and steel hardness, along with end-line-user usage.

Carbide size, volume, and overall percentage, coupled with the hardness of the steel can tell you when a steel is expected to be more brittle (hint: the larger, greater, or higher the numbers are, the less tough the steel will be). Higher steel hardness increases strength (i.e. stability, which is the steels capability to withhold its shape and resist permanent failure, or fracture when enduring stress loads). Whilst there are undoubted "super" charachteristics that high alloyed steel posseses over low alloyed steel, there are trade-offs and limitations to everything.

I do believe that most folks grossly overexaggerate the brittleness of high carbide steels (in usage), along with the need for such intense toughness from their pocket knives. Maxamet being a prime example of a steel that gets harped on for being insanely brittle. This really has more to do with either A) a faulty or non-adequte heat-treatment, which I believe is excessively rare coming from Spyderco (especially these days), or B) user usage and maintenance habits, of which I am more inclined to say is the greatest factor at play when it comes to negative performance reports. Synov linked to a great read over at KSN, which will also help understand why some folks will shun high carbide steels, versus looking deeper at their own potential habits initiating such poor performance (e.g. improper sharpening or misuse/abuse of the given steel). Whilst I believe the article describes some instances and potential causes of negative reports regarding poor performance from high carbide steels that can happen, I still believe to a (much) greater degree that the ELU is the largest and most important variable to consider.

[sal]

I'd like to see s60v get a redemption run. I've only used Shawn's heat treat with s60v so I've been spoiled in that regard.

Hey Steeltoes,

What knife did you use with Shawn's heat treat of S60V?

sal

[Steeltoez83]

I'd like to see s60v get a redemption run. I've only used Shawn's heat treat with s60v so I've been spoiled in that regard.

Hey Steeltoes,

What knife did you use with Shawn's heat treat of S60V?

sal

He gifted me a blank of his sport trapper pattern with it Sal. I assumed s60v was no longer in production so I never posted anything about it. To me I had a piece of unobtanium on my hands.

[sal]

Hi Steeltoes,

Was if finished? Did you use it?

sal

[Deadboxhero]

Hi Steeltoes,

Was if finished? Did you use it?

sal

Sal, I'll just make ya one and you can test it.

[Steeltoez83]

I have used that knife sporadically throughout the years Sal. I keep a 400 grit edge on it to match the cutting patterns I find myself doing. I believe it has a hardness value of 65 hrc if I remember right. Obviously a sample to test is the best way to evaluate properly. I've had no problems with apexing, chips, rolls, or negative experiences with mine.

[sal]

Hi Steeltoes,

Was if finished? Did you use it?

sal

Sal, I'll just make ya one and you can test it.

Love to Shawn. Almost like a new steel, and one that I chose for our introduction of powdered metals into the production market.

I'd like to pay for it or trade you something. If it works well, we might add it to the Mule queue?

Sorry to hijack your thread synov. Back to it.

sal

[ChrisinHove]

I didn’t enjoy sharpening the s60v in my Starmate one little bit. It would be very interesting to see what effect an updated HT would have.

[Synov]

No problem Sal, I enjoy reading about your process for choosing steels.

The data makes me wonder if we are missing out on high edge retention steels that get better toughness from not being as extremely hard as Maxamet and Rex 121. It seems like that space is somewhat unexplored.

[James Y]

I didn’t enjoy sharpening the s60v in my Starmate one little bit. It would be very interesting to see what effect an updated HT would have.

My first Military was the CPM-440V version. I loved the design, but I never used it much, because I'd heard how much of a bear 440V was to sharpen.

I've never had any problems sharpening S30V.

Jim

[Mister Coffee]

@ Synov: Good post. Thank you.

[Naperville]

Hi Steeltoes,

Was if finished? Did you use it?

sal

Sal, I'll just make ya one and you can test it.

I thought that I would ask you. You have had time around Larrin's equipment.

When the graph says Total Cards Cut in mm, I am not sure how to visualize that.

The stack of cards cut has a height in mm? I'm making an assumption here that is what the chart is showing. But the stack of cards to be cut has a width too...is it 2cm to 4cm? So the stack cut is for example, "500mm high x 2cm wide" ?

What is the totality of material being cut? We could be talking about quite a large number...meters of material.