Blade steels - what's wrong with improvement?

[Ankerson]

For the latest Spyderco Mule, Sal ships the USA-made Crucible Industries CPM-S110V steel directly to the Taiwan plant.

This Mule steel is 0.119" thick, flat-ground, and is 0.020" just behind the edge. I suspect it will slice like a laser.
A mule that I've been hoping for...for a long time. I love it. And...you can buy ready-make G10 scales from Halpern...a no-brainer.
Sonnydaze

Yeah it's a cutting machine, mine was .015" -.018" behind the edge.

 

[JParanee]

For me it depends on the maker

Some just have their heat treats so right

Example

Hartsfield A 2

Knight W2

These makers really make these steels sing

On folders I'm really digging ELmax but I welcome the new steels

 

[cujobob]

Elmax has 18% chromium. Must fall apart in your hand.

 

[KennyB]

Elmax has 18% chromium. Must fall apart in your hand.

Lol yup, brittle as glass dang it.

But seriously though...

Couldn't you make a machete just as tough as one made in 1075 carbon steel out of 3V ( and for that matter, much much tougher )?

 

[marthinus]

I find it interesting in that they seem to leave out certain scientific facts backed up by research that don't benefit their positions.

Like I always say science is great as long as it's used in the proper way.

Leaving out key elements of research that doesn't support the position doesn't do anyone any good except for those who have that certain position.

One has to look at all of it combined to see how it all really works together or the big picture is never seen.

Forest through the trees....

Please post your references to scientific journal articles on edge wear, stability, toughness etc. I would love to read them.

My posts tend to be a wall of text with referenced articles and photographs so I wont bore you with that again.

 

[Bo T]

A much tougher machete can be made out of S7, but $$$$$$. The reason that the typical lawn mower blade is made out of low to medium carbon steel is that it can be made for much less $$$ than one made out of S7 or 3V. You can get a 20" mower blade for @ $10. The S7 blade could run $ 100 or more. The s7 blade will hold up better than the low carbon boron blade but, depending on the number of mole hills and rocks you hit, it will require a lot of work at the end of the season. This is one place where the argument for using 1075 steel holds up. Not because it is better, it isn't, but because it is usually more cost effective for the type of work it is being used for.

 

[Ankerson]

Please post your references to scientific journal articles on edge wear, stability, toughness etc. I would love to read them.

My posts tend to be a wall of text with referenced articles and photographs so I wont bore you with that again.

Same books that everyone else reads or references, most of them have to be purchased or go to the library to read them.

Likely a whole section of them them in the library, I know there is in more than one I have been too.

Nothing new really.

 

[sodak]

Someone send me a knife in say 1095 at 64 HRC at .010" or less behind the edge, 5" blade, flat ground with a 1/8" spine to test and I will make a point compared to some of the super steels that I have on hand in like knives on abrasive materials.

I will put a 10 DPS edge bevel on it and cut with it.

And I will show people how fast it goes dull, and it will be very fast when compared to the super steels, there is no way around it..... Even at 64 HRC.....

I made the challenge, it's out there, any takers?

I doubt it.....

Because they already know how it will turn out......

I did that several years ago, M2 HSS 66 HRC. It is 0.1 inches thick at the spine, full convex (that's as close as I have to FFG). I'll send it back to you if you promise to test it, I'd like to know how it stacks up. The gauntlet is down! IIRC, the convex grind caused problems?

No, I am not interested in seeing flexibility, I am interested to see toughness.

Toughness is the resistance of the knife to cracking. Cracks always start at a weak point in the steel, such as an inclusion or a large primary carbide.

Every measure of toughness I've seen on these forums is with respect to impacts. Strength is the measure of slowly loading a steel, which I think is what you have been talking about. I hope a metallurgist will clear this up, but I believe you are mixing these two up.

Why is it always an assumption that in comparisons that a knife made of "super steel" is a "monstrosity" and the better designed knife is made of "older" steel? What about a well designed for the task at hand knife with just the steels being different?

It's the same bias that always assumes the "older" steel has optimal heat treat and the "super steel" has bad heat treat in these discussions.

Good catch. A well made knife in a newer steel will blow away the same knife in the older ones. That doesn't make the old ones bad, that's just progress. I wish someone with a Mule in 52100 and K390 would perform a head to head...

When people try a Phil Wilson (and there are many others as well) with a well designed knife in K390 or CPM 10V, and then finally realize this knife will cut 10 or 20 times longer than an equivalent knife in one of the older steels, they start to understand.

For the latest Spyderco Mule, Sal ships the USA-made Crucible Industries CPM-S110V steel directly to the Taiwan plant.

This Mule steel is 0.119" thick, flat-ground, and is 0.020" just behind the edge. I suspect it will slice like a laser.
A mule that I've been hoping for...for a long time. I love it. And...you can buy ready-make G10 scales from Halpern...a no-brainer.
Sonnydaze

Custom level performance possible with a newer steel at around $100. Truly mind blowing.

 

[Ankerson]

I did that several years ago, M2 HSS 66 HRC. It is 0.1 inches thick at the spine, full convex (that's as close as I have to FFG). I'll send it back to you if you promise to test it, I'd like to know how it stacks up. The gauntlet is down! IIRC, the convex grind caused problems?

I ran that one.

Polished edge though.

You could send it back if you want and I will run it coarse edge to see what it does in comparison to the cutting data I have on the other customs.

No hurry.

 

[Ankerson]

Polished edge, customs....

M2 - 66 - Baseline - 0%

ELMAX - 62 - + 72%

M390 - 62 - + 109%

CPM 10V - 64 - + 162%

 

[marthinus]

Every measure of toughness I've seen on these forums is with respect to impacts. Strength is the measure of slowly loading a steel, which I think is what you have been talking about. I hope a metallurgist will clear this up, but I believe you are mixing these two up.

It appears you are correct. Had to look into some references again. Strength does however become interesting.

The simplist definition I could find is:

Strength
- Simple description: To resist deformation or rolling.
In depth: Strength is most greatly controlled by the Rockwell hardness scale, abbreviated Rc, though different steels can have different yield or tensile strength even with the same Rockwell hardness. The things that factor into this are grain size and alloy in solution. According to Takefu steel (the makers of VG-10) Cobalt strengthens the matrix of steel, regardless of Rockwell hardness. Carpenter steel offers tensile and yield strength numbers of their steels at various hardnesses and the variety of strength numbers while at the same hardness for different steels can be observed. Generally strength and toughness are opposed to each other, raising the hardness lowers toughness. Only decreasing grain size increases both strength and toughness. Higher strength means the edge can be thinner, because the edge is less prone to rolling.(Auth. Larrin Thomas)

http://zknives.com/knives/articles/glossaries/mtlgterms.shtml

Best reference I could find quickly is the following:

"A short list of the important types of mechanical properties includes:
• Hardness, as a measure of resistance to indentation
• Linear elastic constants that relate to strain under tensile, compressive, and shear loads
• Yield strength (under tensile, compressive, and shear loads), indicating the stress level required for the onset of permanent (plastic) deformation
• Ultimate strength (under tensile, compressive, and shear loads), indicating the maximum engineering stress that the material can withstand without fracture. Ultimate tensile strength (UTS) typically is associated with the onset of necking of tension-test specimens (Fig 3.2).
• Fatigue strength, indicating the levels of cyclic stresses that cause fracture due to metal fatigue over time
• Impact toughness, indicating energy absorption from loads that cause very high strain rates (i.e., impact)
• Fracture toughness, indicating resistance to fracture with preexisting flaws or stress raisers in the geometry of a part
• High-temperature creep deformation and stress rupture, where high temperatures cause metals to permanently deform as a function of time
• Damping properties
• Wear-resistance properties (due to wear
mechanisms such as galling, abrasion, and
erosion)"

Arthur C Reardon, 2011, Metallurgy for the non-metallurgist, second edition-Materials Park, Ohio ASM International. Page 50.

From reading the previous sentiment again:

Toughness is the resistance of the knife to cracking. Cracks always start at a weak point in the steel, such as an inclusion or a large primary carbide.

http://www.smt.sandvik.com/en/produc...eel-knowledge/

- Simple explanation: Ability to resist chipping or breakage.
In depth: Toughness is controlled by amount of carbon in solution, the hardness the steel is heat treated to, the carbide size and volume, and the other alloy in solution. High amounts of chromium weaken grain boundaries (though generally carbide size and volume is the limiting factor as far as toughness in stainless steels). Nickel and silicon in moderate amounts increase toughness without effecting strength. Carbide size and volume are probably the greatest controlling factor for toughness. (Auth. Larrin Thomas)

http://zknives.com/knives/articles/g...tlgterms.shtml

Toughness relates to carbide size and strength relates to grain size.

 

[singularity35]

Good catch. A well made knife in a newer steel will blow away the same knife in the older ones. That doesn't make the old ones bad, that's just progress. I wish someone with a Mule in 52100 and K390 would perform a head to head...

Yep, and we need to specify bevel angles.

 

[Bob6794]

As much as I love seeing the progress we have made with knives I can't keep up with buying all these supersteels and honestly have no need to. Right now if I were to build a requirement for my ideal EDC blade steel it be something that I can get extremely sharp and hold it decently long. Not exactly a large set of requirements for me, but I still don't mind experimenting with different steels but I buy my knives mostly based on overall design of the knife more than blade steel or materials. I will admit I do like how certain steels behave more than others but when I am actually cutting something I honestly don't care. I only care about such things when I am testing it or sharpening.

Though one notable exception was the Mule Team 18, I don't think I ever see a chance to test out the S110V or anything like it for such a price and always considered it well out of my price range so when I saw it for sale I jumped at the opportunity. I will own up I bought that knife purely for the blade steel. I still need to reprofile it so I can see what sharpening this type of steel is really like, but for now I am going to try to dull it down which so far looks like it may take awhile.

Out of the 3 more common blade steels I put through it paces recently it would include Opinels carbon steel, SAK stainless, and Rough Riders 440a I would say Opinels carbon steel is easily my favorite followed by the SAK. The 440a just doesn't want to take as good as an edge for me and it loses a good amount of sharpness quite fast and stays at that working edge in terms of sharpness I guess you can say after I cut through 1-2 cardboard boxes, I find it's more noticeable with this steel far more than the other 2.

As you can imagine from my list of blade steels I am not much of a steel snob, but I am trying to focus on my ability to sharpen knives right now. Way I figure it is if I master the ability to sharpen my knives I cut down majority of the reason for me to buy these supersteels and can focus more on buying knives I like for their design than the the materials their made out of.

 

[GatorFlash1]

I never said super steels are a monstrosity, just that some of the knives they are used in seem heavy and cumbersome.

I use super steel blade knives if the rest of the knife is easy and comfortable to use. Cru-wear and M290 are ones I own, S90V also. Great knives made by a great knife maker, Spyderco. Great handles, weight, and blade shape.

 

[cchu518]

I love change and modernity! With that said i personally dont need an Elmax blade to cut my peach at work or that little piece of silk hanging from my tie or the cord that I use to keep my tomato plants from falling down in the summer. I dont make any illusion to what I do with knives vs my two box cutters,, heavy duty cutting shears, camp axe etc
..etc... I also like with the regular steels I can sharpen anything from dull to very sharp in less than a few minutes. Btw 440a is terrific for very light duty work! I have some Chinese knives from rough rider that can cut the crap out of a piece of looseleaf like nobody's business. Also great for cutting loose threads from my shirt, mail, tape on boxes you know like normal regular everyday cutting tasks.

 

[sodak]

Polished edge, customs....

M2 - 66 - Baseline - 0%

ELMAX - 62 - + 72%

M390 - 62 - + 109%

CPM 10V - 64 - + 162%

I got spanked! Ouch! If you want it for a coarse edge reference, I'll send it, but no worries either way. Get well first!

 

[sodak]

Toughness relates to carbide size and strength relates to grain size.

And every time I think I remember the difference between carbides and grains, somebody reminds me that I remembered it wrong. I wish I had time to do this full time.

 

[Sonnydaze]

Although much of the relevant material references found within this thread may be found piece-meal in other places, it might serve well to make it a "sticky."

I know that it didn't take me long to copy this thread link to my Microsoft Word, so that I have easy reference to it in the future.
Thanks to the OP and all of you fine contributors...a veritable wealth of information that is interesting enough to me to plow through seven pages...
Sonnydaze

 

[MattBPKT]

How do you guys define "super steel"? I hear that reference a lot.
Also, I put together a reference table of the composition of the most popular steels for my blog readers. Let me know if I'm missing any big ones!
Thanks

 

[sodak]

I would add CPM 3V, O1, 52100, and 1095.