Top contenders of the toughest steel?

I feel that CPM-3V usually gives knives the upper limit of practical toughness and thus far it's the toughest knife steel by far with such excellent wear resistance. In most cases, the big improvements in wear resistance of 3V over S7 seem to usually justify 3V as the better choice. While 3V is not as tough as S7, it's still dramatically tougher than A2, and yet it holds a much better edge. I was also surprised how well 3V resists corrosion as my expectations were that it would rust like crazy, which it has not at all. I also expected it to be a nightmare to sharpen, which it has not been at all, either. I can understand why some makers offer both S7 and 3V options given the differences, but I think that for most users 3V is a better match.

Like CPM-3V, INFI also has excellent wear resistance relative to its outstanding toughness. Additionally, INFI has improved corrosion resistance. The combination of extreme toughness, good wear resistance, corrosion resistance, and sharpenability make it a very popular steel (and hence Busse a very popular company.) Some of the destruction tests of Busses are almost shocking given how much intentional abusive effort it takes to severely damage the knife.

If looking at impact toughness, 3V at the lower spectrum of its hardness range is dramatically tougher than many popular steels which are already really tough (like CPM-M4 and A2, which are super-tough steels themselves.) So I dare say for 99.999576% of knife usage that CPM-3V gives far more toughness than the usage will ever demand.

My experience with 5160 is limited, but it seems to be really good steel for larger blades as well, plus a great steel for cutting tools designed to cut with impact force, like axes.

With a few new ZT Hinderers coming out in VANADIS 4 Extra, we may find that this is a great candidate in this category as well IMO.
 
Vanadis 4 Extra has a lot more Mo. On paper it looks to be tougher and more wear resistant than 3V. Also some Si. for strength.
 
FFK said:
On paper it looks to be tougher and more wear resistant than 3V.
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I'm fairly sure your comment is not meant to be taken literally (i.e., actually cutting paper).

So what I interpret your comment to read is that your opinion is only based on what you have read or might have heard about the steels being discussed.

"On Paper" many things appear quite different then actual performance.


Personally, I have been quite please with my testing on CPM-3V.

I have a lot of experience A2 and 5160, but feel comfortable going with a thinner cross-section with a 3V blade.



Big Mike
 
Ran across these videos & thought they belonged here. On the first one a maker tests A2, O1, & 3V clones.


[video=youtube;TSVs2LCZ-TQ]https://www.youtube.com/watch?v=TSVs2LCZ-TQ[/video]


1095 vs 5160 in another maker's torture test for machte blades:


[video=youtube;02u7X6Mb_RM]https://www.youtube.com/watch?v=02u7X6Mb_RM[/video]


A video about CPM3V not being the toughest out there:

[video=youtube;if1d8JEBy-0]https://www.youtube.com/watch?v=if1d8JEBy-0[/video]
 
FFK said:
Awesome chart........I am a S7/S5 fan as well. What is your opinion of S5. Has a lot more Si vs Mo. in it. S7 has the opposite, more Mo. than Si. Depending on the chart it appears that S5 is tougher and more wear resistant.
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HELLO Mike!
Have you made any knives or tested any production/other makers knives made from S/7 or S5? Please share your test finding's with use.
 
Heard this theme again and again.
"Best for the knife I make and available in the sizes I need to make it."

Making a slicing knife that's going to get wiped clean after every slice? Go with the hardest thinnest edge you can produce in the material that will allow you to get there.

Making an entry tool/emergency tool/rock crusher? Go with the thickest, steepest bevels and material that will still perform the job, in a material that will allow you to get there.

Making a knife for the buyer who what's the "latest thing" in "wonder steel"? Find the most exotic thing you can get your hands on and make a knife in whatever size that steel comes in.

I'm not trying to squash any arguments or start anything, just pointing out that there is no "best" steel or "toughest" steel. It really depends on the job the tool is designed for.

There is and will never be a "universal" shaving sharp pry-bar that weighs 5oz and is 15" long in a mirror finish that can flex to 90 degrees and return to true without taking a set, while at the same time resisting rust completely and being affordable.

I look at it this way:

1. An OK steel will give you one of the top five things you want.
2. A good steel will give two of the top five.
3. The best steel will give you 3 out of five.

I think it always comes down to:

1. Intended design.
2. Availability of materials.
3. Affordability of materials.
4. Limits of design and materials.
5. End-users use of the intended design.

I'd love to see a more comprehensive set of standards for typical knife designs that knife makers could adhere to and be judged against, rather than just resorting to hammering knives through various types of media... I mean really, when was the last time you actually took a hammer and hit ANY of your knives. Ever. For any reason? I know I don't. I get a saw if I want to cross-cut wood, and a chisel if I want to take gouges. I get that the "survival" theme means abuse the hell out of whatever you've got in your hand... but even there. I'd like to see some global standards for abuse.

Look at how most tools are made. Typically for ONE purpose. And when use for that purpose they work as well or better than intended. And when used for other things, they're not expected to perform.

I think we need to get away from "how much abuse" can our knives take, and work towards actual "use standards". I mean lets face it, if you want the best survival tool available, read a book, go for a hike, train your reflexes, learn about weather, and physics and chemistry and plant pathology. Become the survival tool, don't expect any one thing to do it for you.

Rather than saying "the best knife is the one in your hand when you need it" say "I've learned to survive without a knife".

Just thinking out loud.

- Hal Zucati
 
It's always dangerous to rely entirely on a chart like that, especially when it's been compiled from various other charts and/or datasheets of unknown (to me) origin. But it does seem to jibe with what I can corroborate about the various steels, and I appreciate that you listed hardness values for each one. For instance, you show 3V at 60Rc, which is a good spot for it... but at 58Rc 3V is dramatically tougher and still has almost the same wear-resistance. To put together a truly representative chart would require at least 2 or 3 test pieces of each steel with the same geometry at various hardnesses, a Charpy tester, a Rockwell tester, a CARTA machine, re-testing/peer review, thousands of dollars and probably weeks if not months of lab time. Ain't no one got time for that.

halzucati said:
I made the following chart after researching this issue of "toughest steel. I used close to 20 separate graphs and countless articles to compile the data that I used to come to the conclusion that for my purposes S7 was the Tough/Price/Availability sweet spot.

65962_1541132516114900_5806160483216506614_n.jpg
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The "1095 is toughest" crowd ain't gonna like it too much, though :D

Again, all those steels are "tough enough" for most relatively sane people who use knives to cut, slash and chop things. And as you mentioned in your next post, you can make up for less toughness with sturdier geometry - thicker spines, less-keen bevels and stout edges. You and I seem to be very much in agreement that many factors - including intended use - should be considered and balanced. :thumbup:
 
The_Knife_Man said:
With everyone wanting a folding pry bar nowadays; who would be top contenders of the toughest steel?
Next comment will be "define tough"...
So, tough as in, can beat the hell out of it and not thing twice about it. Use to pry stuff if necessary.

Ya, ya, I hear ya. Using a tool not for its intended purpose.
For discussion sake; is it M4, 3V, perhaps something else.
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Ill start off that I don't have much steel experience. And really use my knives in the "pry bar" sort of way and personally I prefer being able to put a edge on in the field and then being able to hold that edge.

I'd say a 1095 with a good heat treatment. I don't have any experience with much of the super steels but I doubt that it'd be much better than a good 1095, especially for the price. 5160 is pretty good too, considering that it is spring steel. I have a few knives in it, just haven't had a chance to really use them yet.
 
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I'm a little surprised that D2 is tougher than 1095 according to the chart. I always thought it was the other way around. And I thought that L6 would rank higher. Oh well, I guess you learn something new every day
 
C_Becker said:
I'm a little surprised that D2 is tougher than 1095 according to the chart. I always thought it was the other way around. And I thought that L6 would rank higher. Oh well, I guess you learn something new every day
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For those reasons, any charts like that are pretty suspect. There is no reason to think that 1095 is less tough than D2 unless there is something wrong or the hardnesses are not comparable.
 
me2 said:
For those reasons, any charts like that are pretty suspect. There is no reason to think that 1095 is less tough than D2 unless there is something wrong or the hardnesses are not comparable.
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Just as a reference, Crucible uses charts, graphs and a ton of text when talking about this subject... They mention a lot of the areas I brought up and note that compromise is the name of the game when using their products.

Hard vs. wear vs. tough.

They even show in one of their charts what was mentioned by James that 3V is tougher at lower Rc hardness levels... again compromising.

Also I think we should be careful in assigning meaning to the term "tough". Crucible is careful to site specific tests as their definition of tough is described. Using that as a reference, how often are you going to subject your knife to that type of stress as is used in the various tests? Like, cut a notch in the steel then whack it with something? Not likely. Only one of those tests is even remotely real world outside of extreme outside cases.

Lastly, lest this become a competition or honor based comparison of who's steel can beat up whom... I think based on the specifics outlined in Crucible's article there is no other conclusion that under those specific circumstances 1095 IS less tough than D2 or S7... but in a real world situation?

As noted before, you'd have to setup a whole new series of tests, and as I suggested, you'd need a whole new set of standards and then lots of time, money and data to develop another set of test-specific results.

Very interesting read:

http://www.crucibleservice.com/eselector/general/generalpart1.html

After you've read through this, see if it changes or updates you opinion. Perhaps its time to make your own steel, like Busse's INFI and garner a whole crowd of folks who believe that IT is the new king of steel. Sometimes the sizzle IS tastier than the steak, sometimes not.

- Hal Zucati
 
I have used most of the steels mentioned but not all. S7 has been the "toughest" so far. I have owned several Busses and like Infi but it is not S7.
 
I've read that before. It helped form my current opinion. You'll get no arguement from me that S7 is tougher than D2 and 1095. However, there is no reason to think 1095 is less tough than D2, or L6 less tough than A2, particularly at lower hardness, unless there is something wrong with the 1095 or L6. For that reason, charts like that, particularly in isolation, are questionable.
 
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me2 said:
I've read that before. It helped form my current opinion. You'll get no arguement from me that S7 is tougher than D2 and 1095. However, there is no reason to think 1095 is less tough than D2, or L6 less tough than A2, particularly at lower hardness, unless there is something wrong with the 1095 or L6. For that reason, charts like that, particularly in isolation, are questionable.
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Well said.
 
me2 said:
For those reasons, any charts like that are pretty suspect. There is no reason to think that 1095 is less tough than D2 unless there is something wrong or the hardnesses are not comparable.
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I find that 1095 has a lot of variation in toughness. Many of the charts that show it as having lower toughness seem to rank 1095 heat treated to a higher hardness.

The chart above shows 1095 at 58 HRC. My Ontario RAT5 is 55-57 and to my understanding 55-56 is more like it. At least thus far, I've never used a D2 knife that I would consider remotely comparable in toughness to the 1095 on my RAT. It may exist, but I have not encountered it. (And on the flipside, my RAT does not have wear resistance that I would consider remotely comparable to any D2 I have used.)
 
I have used INFI hard, and hit targets that I did not mean to hit. Chopped a small stone in half on my chopping block. I have also hit many rocks in the ground when chopping limbs without a proper backrest. It does very well for impact, shock and flexibility. It is not quite as tough as the shock steels, but pretty much stainless for my uses, and holds an edge longer, than the S7 that Scrap yard used to use. Their SR101 (52100) is fantastic too.

There are a lot of other high end steels that I have not tried, though.
 
C_Becker said:
I'm a little surprised that D2 is tougher than 1095 according to the chart. I always thought it was the other way around. And I thought that L6 would rank higher. Oh well, I guess you learn something new every day
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And I thought 5160 at 58 RC would be tougher than O1 at 58 RC ;)
 
me2 said:
Is anyone out there making knives out of 4140 or 4340? I have seen it for axes and hawks, but not knives.
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I'm pretty sure that Casull uses 4140 for their revolvers. I'm not sure being proof tested to 90K psi qualifies for knife toughness though. :D

I've done lots of non-scientific chopping, and in my collection, CPM 3V is on top, and INFI is second to it, both in toughness and edge holding. Toughness is fairly close, 3V's edge holding is noticeably better. Both are very good, however. I would be comfortable with either steel if I needed toughness.

Has anyone send an INFI knife off for testing? It would be interesting to see how it stacks up in a lab.
 
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