Blade steels - what's wrong with improvement?

[RamZar]

I'm impressed by the wear resistance and edge retention of the newer super steels like M390. Also, the introduction of existing tool steels for blades like M4, 3V and Sleipner. Also, taking tool steels and making them more stainless like CTS-XHP and Niolox. I'm sure there are existing metal alloys out there that'll be discovered as great for blades with or without tweaking the composition and heat treat.

 

[marthinus]

Why? Flexibility is a function of geometry. Just grind it thin if all you want to do is show it can flex 90 degrees. It's really not that big of a deal.

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.

http://www.smt.sandvik.com/en/products/strip-steel/strip-products/knife-steel/knife-steel-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/glossaries/mtlgterms.shtml

That is why the blade is examined after the test.

The ABS bending test has nothing to do with cutting performance. It's strictly to see if a smith can differentially HT a blade. Their words, not mine...

And you completely overlooked the other tests done prior to the bend test?

1. ROPE CUTTING: THE PURPOSE OF THIS TEST IS TO TEST THE EDGE GEOMETRY AND SHARPNESS.

2. WOOD CHOPPING: THE PURPOSE OF THIS TEST IS TO DEMONSTRATE EDGE TOUGHNESS.

3. SHAVING HAIR: THE PURPOSE OF THIS TEST IS TO DEMONSTRATE EDGE RETENTION.

4. BENDING: THE PURPOSE OF THIS TEST IS TO SHOW THAT THE APPLICANT IS ABLE TO HEAT TREAT A KNIFE WITH A SOFT BACK AND A HARD EDGE.

Whether or not that's important to you is a matter for a whole different thread, and has been beaten to death long ago.

As has this discussion. But it will come up time and time again as long as there is knife discussion.

Frankly, I prefer hard use blades that neither bend nor break...

That is your personal choice, I wont question you on that. You buy and make what you want and like. Your customers like that and support you.

 

[james terrio]

Thanks for clearing up what toughness means for us. I'm sure that will be very helpful for many folks reading this thread :thumbup:

And you completely overlooked the other tests done prior to the bend test?

Nope. I read the whole thing. I've also discussed it at length in person with a couple JS and MS stamp holders.

 

[shqxk]

because they are usually not all out "better"

high alloy steels trade out wear resistance for massively decreased strength and edge stability. if you want a pocket scalpel that is sharpened flat down on the stone for a tortuously thin, acute edge, you won't go for these new high carbide steels, because they simply can not keep up with a good carbon steel (or rare, low carbide stainless) at these levels of extreme edges.

that said, my personal favorite is cpm m4. but I admit to myself that cpm m4 will have very limited strength, and low edge angle stability compared to some "outdated" steels. it is "better" for me when I want an obtuse thirty degree edge and need to cut up hundreds of yards of abrasive material with no sharpening. but to say it is all out "better" than even the steel in my opinel is being extremely subjective and biased, because the simple carbon steel is equally "better" at other tasks.

Totally agreed.

High carbide = more wear resistance but less strength/edge stability/sharpenbility

To much hype on extremely high carbide steel IMO

I have been used and tested almost every steel some people considered "super" or "exotic" steels like K390, M390, 10V etc. It's sure a great steel for some specific task but I wouldn't rate those as superior steel than the plain carbon one.



Every steel has it place

 

[shqxk]

I use 52100 extensively in my knives and use AEB-L as well. They are an exception as they have the finest grain structures of any steel which is something that makes them perform very well. I absolutely love 52100. I use it in everything from razors to skinners to tomahawks and machetes. Its probably the most well rounded steel out there if you ask me and will excel at everything from fillet knives to katanas.

That said 3V is probably better than 52100 for anything but a razor blade or kitchen knife. It has better edge stability, cuts more aggressively, is significantly tougher at the same hardness and has about 2.5X the edge retention on most things. You can run 3V at 62 and its as tough as 52100 at 57-58.

BUT Its also 3X as expensive and the cost is not worth the increase in performance much of the time. 52100 is amazing and I plan to continue to use it until a better steel comes along at a similar price point.---which hasn't happened yet and probably won't for a long time if ever.

Where did you get those number?

My friends who both a bladesmith and I have ever done a test among three cutting competition style knife. One is 52100 HTed by the recipe of Kevin Cashen, another blade is 3V HTed by Paul Bos and the last one is a cutting blade from Diaz tool which is M4 HTed by Peters.

After cut so many 2x4 by 3 men we can't really tell the difference between M4 and 52100 while 3V edge has noticeable taken much more damage than the others.

 

[leghog]

I wouldn't want to skin a bunch of wild boars with a knife in AEB-L or 52100 (Would be sharpening it a lot)...

Seriously? Just how often does one skin "a bunch of wild boars with A knife"?

 

[Bo T]

There is a very large spread in cost in even 1095 blades, from like $10 to thousands depending on the knife and who made it.

Especially those 'collector' knives. But, If I can find an equivalent pattern to the Green River belt knife in S125V (for $15), that has a good HT, I'll buy it. Heck, I'd pay $30 for just the blade! But, it would be difficult (mentally) for me to pay much more than that. For most people it comes down to desire more than need. The 'modern' steels will give a user better edge retention, greater strength for a given profile (given a good HT), and better corrosion resistance. All this comes with, as noted, an added cost.

 

[chiral.grolim]

...Edge stability is a wonderful thing, but all of that in the world won't help if you can't cut anything with the blade because it dulled too fast.

And that is the difference, especially when cutting abrasive materials, if the alloy content isn't there, it's just not there.

And all the 50X magnification and or 500X magnification isn't going to make any difference because it just doesn't matter because one blade still cuts and the other is bone butter knife dull.....

Yeah that high edge stability is great, nice and smooth, can't cut anything with it, but it's got great edge stability......

That's what happens when the scope is narrowed down too much, you miss the forest through the trees......

While scientifically correct and backed up with all sorts of literature and pretty pictures from a number of places by some very smart people.....

One still can't get around dull vs still cutting....... No matter how it's slanted to show the point one is trying to make and how technicality correct it is.

:thumbup: ^This is the key point often missed in discussions of edge-stability, that in cutting abrasive material (e.g. cardboard) the fine 0.1 micron apex diameter is lost almost immediately and the ultra-fine 52100 blade is just as dull as the CPM-10V blade within the first meter or so, and after that first meter the CPM-10V blade holds its apex-diameter (i.e. sharpness) and even ends up with a more jagged (toothy) profile while the other continues to thicken and smooth out, i.e. "dull", "can't cut". This can be mitigated by stopping to strop the edge now and then to keep the lower-carbide steel at optimum sharpness, but it will lose it again just as fast as before.

I have shaved with CPM-3V and M390, they can certainly be brought to a fine enough edge for the purpose, but studies suggest that M390 at least will not keep that fine face-shaving edge as long as 52100 or AEB-L, collapsing to an excellent "working edge" for other purposes ... just not shaving. So if you don't need a very-fine apex ... *shrug*

 

[Ankerson]

:thumbup: ^This is the key point often missed in discussions of edge-stability, that in cutting abrasive material (e.g. cardboard) the fine 0.1 micron apex diameter is lost almost immediately and the ultra-fine 52100 blade is just as dull as the CPM-10V blade within the first meter or so, and after that first meter the CPM-10V blade holds its apex-diameter (i.e. sharpness) and even ends up with a more jagged (toothy) profile while the other continues to thicken and smooth out, i.e. "dull", "can't cut". This can be mitigated by stopping to strop the edge now and then to keep the lower-carbide steel at optimum sharpness, but it will lose it again just as fast as before.

I have shaved with CPM-3V and M390, they can certainly be brought to a fine enough edge for the purpose, but studies suggest that M390 at least will not keep that fine face-shaving edge as long as 52100 or AEB-L, collapsing to an excellent "working edge" for other purposes ... just not shaving. So if you don't need a very-fine apex ... *shrug*

It's not missed, it's just not allowed to be be discussed due to being covered in data, walls of text, photos, and links to technically correct information.

Because the discussion is usually slanted in favor of the lower alloy steels so the data, usually tons of it, has to be narrowed down to a very specific area to support that position. And it is VERY NARROW because it has to be...

In all of that what is forgotten is a knife is supposed to actually cut stuff so that part is left out or buried under tons of research because that's not the point that is being made.

So while scientifically correct and backed up by research the key element is often left out that will bring it all back to reality.

And anyone who mentions it will be covered in walls of text etc......

 

[precisionshootist]

After reading posts from steel experts on this thread it still sounds to me like steel qualities are mostly a trade off. If you gain in one area you will lose in another. So to go back to the original question "what's wrong with improvement" I would say nothing when there is actual improvement but the posts from steel experts indicate increased performance when the steel is matched to the task. That's not "improvement", that's "optimization" which is something I can't do for a knife I'm going to be carrying around in my pocket or on my belt and will be used for an unlimited myriad of tasks.

Lastly, I still have my doubts about being able to tell the difference in day to day use. Take a hypothetical test of say ten Spyderco Enduras of which five are made from any new super steel and five are made with outdated ATS34. Have the tester start using them and see if they can separate the knives correctly into piles of each steel based on performance. I don't think the results would be consistent.

 

[Ankerson]

After reading posts from steel experts on this thread it still sounds to me like steel qualities are mostly a trade off. If you gain in one area you will lose in another. So to go back to the original question "what's wrong with improvement" I would say nothing when there is actual improvement but the posts from steel experts indicate increased performance when the steel is matched to the task. That's not "improvement", that's "optimization" which is something I can't do for a knife I'm going to be carrying around in my pocket or on my belt and will be used for an unlimited myriad of tasks.

Lastly, I still have my doubts about being able to tell the difference in day to day use. Take a hypothetical test of say ten Spyderco Enduras of which five are made from any new super steel and five are made with outdated ATS34. Have the tester start using them and see if they can separate the knives correctly into piles of each steel based on performance. I don't think the results would be consistent.

ATS-34 isn't outdated, it the same as 154CM and that is still used as is the PM steel CPM 154.

Everything is a trade off, and that has been discussed a number of times over the years.

It all comes back to my 1st post in this thread...

Wants and needs...

 

[Gator97]

My argument is simply that there is no be all end all of steels. I used the ABS test as a simple example.

Mine was the same, no matter how old and well tested alloy is, there are always new and better ones coming up, no need to get stuck in the past. I wasn't proposing to use 10V for everything, it has its purpose just like 3V or whatever else. Same is true for 10xx, 440C and whatever else. Some alloys might be more versatile than the others, but I don't see that as an argument against new alloys.

 

[chiral.grolim]

Steels like 440C or D2 or the 'low-end' powder steels like S30V are ones I question being used in a knife for any reason other than cost of manufacture or limited skill of the maker. They are less wear-resistant, less tough, less corrosion resistant, less "edge-stable" - Inferior on all counts, no? But the gains in each of those attributes is simply insufficient to justify the added cost of production to the average user...?

 

[Gator97]

My problem with the "super steels" is I see very little VERIFIABLE difference in performance. I have my doubts if anyone could consistently tell the difference with identical unmarked knives between high quality stainless steels in real world performance.

There is a lot of it too. Difference between 10xx or 52100 and high vanadium alloys at high RC will be easily detected during sharpening phase, and even sooner during cutting abrasive materials, e.g. cardboard. Especially with thin edges, which is one of the benefits of new alloys, nobody really mentions.

The trade off is harder steel stays sharp longer but by definition will take equally longer to sharpen.

Not at all. Like Ankerson said, and I can only confirm that fro number of high alloy, super hard knives that's not the case at all. Bringing dulled edge back is as easy or sometimes even easier that on the low alloy knives. If you to same amount of cutting, 10xx will suffer a lot more damage, because it gets dull faster, dull knife means you need to exert more fore, and induce more edge deformation and damage, etc. So, you will spend more time restoring that edge. If you try to keep up with 110V or 125V then you have to sharpen 10xx steel few times more ofter. In short, unless you are grinding a knife form a blank, or rebeveling the edge "equally longer time" is never the case.

 

[bdmicarta]

steel qualities are mostly a trade off

Yes, but newer steels change the nature of the tradeoff, allowing you to improve one of the properties without detracting from the other. You still have to choose which property is most important to you and choose a steel accordingly, but it is getting better.

 

[Big Chris]

In day to day tasks that involve cutting I can honestly say that I can pick an O1 knife from a 3V in around 5 minutes of use. Now to distinguish between 3V and M4 or 10V may take a little longer, but believe me it will show and you will notice a lack of cutting ability. I know this because I have done the comparisons numerous times. I have worked with almost all the steels mentioned in this thread and all that I work with work differently, cut differently, and dull differently. I have EDC'd knives I made from O1, 3V, M4, S90V, 10V, M390, ELMAX, 4V, CPM 20CV, D2, CPM D2, and PSF 27 to name most. I cut a lot of cardboard, paper, wood and plastic on a daily basis and differences show up very fast, especially in cardboard. In my use O1, ELMAX, and D2 dull the fastest. They would be the first separated into a pile. The PSF 27 and CPM D2 are very hard for me to tell apart in use, but they will last almost as long as the 3V. In multiple tests it could be difficult to pull the 3V knife from these other 2. The next group will include M4, 4V, 20CV, and M390. Finally you are left with S90V and 10V. I really do not see how anyone who has used these 2 steels can say they are not well rounded steels or that 52100 or AEB-L can stand next to them. I have used both 52100 and AEB-L and I would never make such a claim with a straight face. I have chopped 3/8" Poly-Carbonate sheet with S90V and experienced no edge damage. I have batoned both 10V and S90V through golf ball sized and larger cedar knots with no major edge damage. I have cut more cardboard with an S90V knife than any other and I usually run out of cardboard before the edge stops cutting. I have made several 10V hunting knives that were ground to .008" at the shoulders and used to process game. At a high hardness of 63 to 64 Rc there is plenty of edge stability to hold that fine edge. No, I would not recommend sticking the edge in a joint and prying sideways, but I would not do that with any steel. A few cuts around the joint and it separate on it's own. I do not just make knives, but I try to use them hard too. I try to push the edge geometry thin till it fails and then thicken it up till no failure occurs. These super steels might not like to bend and flex like the spring steels, but they were never intended to do so either. I just found out the other day that 10V was designed in the '70's to cut very large stacks of cardboard and paper. It is intended to be hard and stiff, but not brittle. I doubt that a spring steel that will bend and flex would make dead straight cuts or as many cuts as a 10V blade. 10V has an equal toughness to D2, it is just not found in larger blades because of the cost to produce.
Sorry about the ramble, I do not normally make posts this long. Yes the super steels are more expensive and you could get by with a piece of cheap Chinese surgical stainless. A new truck is also expensive when the old Ford Pinto or Chevrolet Chevette will get you to your destination. Advancing technology, improved performance, and bragging rights all play a part in our purchases. An old Colt 45 will shoot as good as a new Colt 45 but neither will be as accurate or perform as well as a Les Baer. O1 or 1095 will get the job done but will not perform as nice as a well made knife from CPM 10V.

 

[Gator97]

Where did you get those number?

Toughness and other properties generally are in the alloy datasheet, which is distributed by its maker.

After cut so many 2x4 by 3 men we can't really tell the difference between M4 and 52100 while 3V edge has noticeable taken much more damage than the others.

Dunno. Too many factors to consider. 3V is tougher by specs, and I don't believe in voodoo either.

 

[Anarkistic]

Most knives us enthusiasts collect are military/bushcraft/survival blades. ESSENTIAL QUALITIES of a blade made for such a purpose is TOUGHNESS and EASE OF SHARPENING.

Carbon is superior to stainless regarding these two qualities.

There's a fundamental problem with stainless, when you start throwing a sh*t load of chromium into steel, it becomes brittle and that's bad news.

 

[KennyB]

Most knives us enthusiasts collect are military/bushcraft/survival blades. ESSENTIAL QUALITIES of a blade made for such a purpose is TOUGHNESS and EASE OF SHARPENING.

Carbon is superior to stainless regarding these two qualities.

There's a fundamental problem with stainless, when you start throwing a sh*t load of chromium into steel, it becomes brittle and that's bad news.

Except that modern alloys contain enough other elments that they're often much tougher than a non-alloy simple carbon steel while also being stainless, even at 60+ HRC hardness levels so they'll also be much more wear resistant at the same time.

 

[marcinek]

Most knives us enthusiasts collect are military/bushcraft/survival blades. ESSENTIAL QUALITIES of a blade made for such a purpose is TOUGHNESS and EASE OF SHARPENING.

Carbon is superior to stainless regarding these two qualities.

There's a fundamental problem with stainless, when you start throwing a sh*t load of chromium into steel, it becomes brittle and that's bad news.

There doesn't appear to be a whole lot of facts in that post.