What's the toughest powdered metallurgy stainless steel?

ALLHSS said:
I just feel like as a stainless steel, s30v should be pretty tough per its make up. Am I wrong?
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The fact that it is harder to grind does not make it tough in terms of impact resistance and edge stability. That just means that it is hard to grind.
 
The question is kind of pointless since virtually no production companies make knives in the premium stainless steels where 'impact' capacity would even matter, that is to say, large fixed-blade bowie styles or machetes. I think Bark River makes a few 4-5 inch blades in S35V. 'Impact' isn't really a factor for a folding knife, and if it is then I know for sure that my Manix XL in S30V is all anyone could ever need.

As for edge retention, a youtuber, Smokeeater908 did a very impressive string of videos comparing the cutting performance of CTS-XHP, M390, S30V, S35VN and Elmax. Besides Elmax, all the other steels were Spyderco Millie/Paramilitaries. In his tests, ZT Elmax failed miserably, being comparable to a 'Smith&Wesson' knife. S30V easily outdid S35VN and just barely traced CTS-XHP and M390.

I'm a knife newb, but even so I'm educated. The prevalent S30V hate on this forum just reeks of counter-fanboyism.
 
Bugout Bill said:
The fact that it is harder to grind does not make it tough in terms of impact resistance and edge stability. That just means that it is hard to grind.
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Yeah I didn't say anything about how hard to grind it is. S30v is a tough steel. Period. Not the toughest, but tough.
 
ALLHSS said:
Yeah I didn't say anything about how hard to grind it is. S30v is a tough steel. Period. Not the toughest, but tough.
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Compared to what and what sort of geometry?

I'm not saying S30V is a chip fest, far from it. I have subjected my Spyderco Military to convince me it is a good steel. But it isn't 3V or 5160 by any means.
 
evosbu1 said:
The question is kind of pointless since virtually no production companies make knives in the premium stainless steels where 'impact' capacity would even matter, that is to say, large fixed-blade bowie styles or machetes. I think Bark River makes a few 4-5 inch blades in S35V. 'Impact' isn't really a factor for a folding knife, and if it is then I know for sure that my Manix XL in S30V is all anyone could ever need.

As for edge retention, a youtuber, Smokeeater908 did a very impressive string of videos comparing the cutting performance of CTS-XHP, M390, S30V, S35VN and Elmax. Besides Elmax, all the other steels were Spyderco Millie/Paramilitaries. In his tests, ZT Elmax failed miserably, being comparable to a 'Smith&Wesson' knife. S30V easily outdid S35VN and just barely traced CTS-XHP and M390.

I'm a knife newb, but even so I'm educated. The prevalent S30V hate on this forum just reeks of counter-fanboyism.
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Well I do have a large bowie in s35vn and its done very well chopping and general camping chores.
 
Bugout Bill said:
Compared to what and what sort of geometry?

I'm not saying S30V is a chip fest, far from it. I have subjected my Spyderco Military to convince me it is a good steel. But it isn't 3V or 5160 by any means.
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Of course not. Sure, other steels exist that are tougher. I'm out.
 
Bugout Bill said:
Aebl?
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AEB-L is an ingot steel.

CPM-3V/Z-Wear/Vanadis 4E should be the top contenders, but you sacrifice corrosion resistance. If corrosion resistance is important combined with higher alloy content...heck I dont know. It becomes a gray area for me but I know carbide volume becomes important.

From crucible:

Recommondationsfromcrucible_zpsdc94dbb8.jpg


The main constraint to higher alloy content is the volume of primary carbides.

Crucibles patent information on CPM-3V shows the following graph:

CPM-3V_zps1acb61fa.jpg


Powdered/Particle/Spray formation improves higher carbide containing steels, however, in industry High Strength Low Alloy steels still have greater toughness than steels with higher percentage carbide volume. That is why L6 is still used for jackhammer bits and other high impact uses.

If you want stainless and toughness 12C27 (not a PM steel) is one of the best available IMO as it is a low alloy steel with small carbides. Most custom knife makers I have talked to run their 12c27 at HRC of 60-61.

http://www.smt.sandvik.com/en/produ...ge/different-steel-types/fine-carbide-steels/
 
Nathan the Machinist said:
Elmax at HRC 60 and 13 degree per side can cut nails. Wanna try that with S30V? Elmax with an edge thickness before sharpening of only .025 can be driven point first through a cinderblock. Name another stainless steel that can do that. And at 1.7% carbon and 3% vanadium it's not just tough, it holds an edge in abrasive materials and has good fine edge stability. What's not to love?

[video=youtube_share;NO3pmcyr8wA]http://youtu.be/NO3pmcyr8wA[/video]

There are a few big manufacturers using it and doing the HT themselves and at least one of them isn't doing a great job. If you've tried Elmax on a production knife and weren't impressed you might try a custom, it will blow your mind.

S30V isn't even in the same ballpark.
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Which manufacturer isn't doing a great job? And, I assume the custom makers do the heat treat themselves, so won't it vary in quality ?
 
jac_solar said:
Which manufacturer isn't doing a great job? And, I assume the custom makers do the heat treat themselves, so won't it vary in quality ?
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A lot of custom makers use commercial HT companies, as thermal processing of steels like elmax and the SxxV series of steels requires lot of precision and equipment that really aren't feasible for an individual.
 
I'm sorry, but judging a knife on its ability to cut through nails and cinder blocks is like judging a hammer by its ability to spread jam on your toast.

I know it's for the sake of a toughness test, but I'd rather see more practical knife tests. In no situation would I ever need to use a knife to pound through nails and a cinder block with a hammer.
 
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Cassull said:
I'm sorry, but judging a knife on its ability to cut through nails and cinder blocks is like judging a hammer by its ability to spread jam on your toast.

I know it's for the sake of a toughness test, but I'd rather see more practical knife tests. In no situation would I ever need to use a knife to pound through nails and a cinder block with a hammer.
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Don't disregard physical characteristics because of the test used to demonstrate them. Abuse tests like that may not show the typical or practical use of a tool, but it does show the toughness to some degree.

If someone is asking about toughness, they don't want people cutting paper as a method of demonstration. Typically, in situations like this, someone is looking for a material that has such impressive capabilities that they never have to worry about exceeding them.

It's one of the reasons I keep eyeing the Warcraft Tanto and the Survive GSO 5 - big, beefy knives made out of unobtanium. It's hard to beat the knowledge that you are carrying something that could be hammered through a pipe without suffering catastrophic damage.
 
I personally love Nathans tests. IMO if a knife can go through a cinder block and not have much edge damage. You shouldn't have to worry much about edge damage using it as a camp knife. It's nice to know it can hold up to major abuse.
 
It's a non-contextual test, so its meaningless. Its like those .45ACP owners who demonstrate the magical stopping power of a .45 by shooting steel plates and fawning over the louder noise and how much more the plate sways compared to a 9mm, and this is coming from a .45 owner. Doesn't change the fact that a 9mm will kill a human just as surely as a .45ACP, which after all is the purpose of that technology.

At least for us average joes who ask such questions like OP, knifes are for cutting. Hammering a knife through "a pipe". Where and why would I ever do this? Whatever isolated potential that may exist is meaningless if it doesn't contribute to the purpose of a tool, but here it's cherry-picked to justify more S30V hate. Spine-whacking folders is a similarly foolish idea.
 
Cassull said:
I'm sorry, but judging a knife on its ability to cut through nails and cinder blocks is like judging a hammer by its ability to spread jam on your toast.

I know it's for the sake of a toughness test, but I'd rather see more practical knife tests.
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Oh yeah, absolutely. They're documented in this thread: http://www.bladeforums.com/forums/showthread.php/1161651-Cut-testing-3V-heat-treat-ELMAX-D2

Those tests are slow and tedious and don't really need video documentation but they are very important and are the more "scientific" tests.

And even then, taken out of the context of a long series of numerous tests involving many different knives even those tests are fairly meaningless. That test was only evaluating a tweak in the heat treat of 3V. Elmax was thrown in for curiosity's sake. But, during the course of that evaluation Elmax did exhibit what, in my experience, represents a very unusual level of durability for a stainless. And since it was documented and relevant to this discussion I showed it to you. I acknowledge that, in of itself, it proves nothing.

Cassull said:
In no situation would I ever need to use a knife to pound through nails and a cinder block with a hammer.
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A person should never assume that their point of view or way of seeing things is the only valid point of view. While you may use your knives to spread jam on toast some people find themselves using their knives to pry open glove boxes and open holes in walls. And they're not "knife enthusiasts" testing a knife for fun, they're people who carry knives in their gear and wouldn't hesitate to beat them to death under certain circumstances.

Regardless, the OP asked what is the toughest stainless steel. And while tough can mean energy absorbed in an impact test, where unhardened 18-8 tableware cutlery would probably reign supreme with the highest charpy impact numbers. I think most of us understand that blade durability in real word use boils down to more than a number and edge durability often goes contrary to gross blade durability. So in a complex matrix like that where laboratory tests are not always more meaningful than real world use and abuse one might find themselves cutting nails in controlled comparison tests (that don't generate numerical values) to evaluate an alloy or heat treat compared to other standards. And in these kinds of tests I've been very impressed with properly heat treated Elmax.
 
evosbu1 said:
It's a non-contextual test, so its meaningless. Its like those .45ACP owners who demonstrate the magical stopping power of a .45 by shooting steel plates and fawning over the louder noise and how much more the plate sways compared to a 9mm, and this is coming from a .45 owner. Doesn't change the fact that a 9mm will kill a human just as surely as a .45ACP, which after all is the purpose of that technology.

At least for us average joes who ask such questions like OP, knifes are for cutting. Hammering a knife through "a pipe". Where and why would I ever do this? Whatever isolated potential that may exist is meaningless if it doesn't contribute to the purpose of a tool, but here it's cherry-picked to justify more S30V hate. Spine-whacking folders is a similarly foolish idea.
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You wouldn't abuse your knife. But you would use it to open a case of beer. And when the edge clinks against the glass bottle it will flatten ever so slightly. So if one alloy or heat treat has better edge stability than another, it probably still matters to you. And there is a correlation between cutting a nail (which you would never do) and bumping your edge against something hard, which you probably do more than you realize. Wouldn't you prefer the manufacturer who made your knife gave some attention to these things with tests like this:


7.jpg~original


Same steel, same hardness, same edge geometry (13 degrees per side), same nail you would never cut. The difference was in the timing and sequence of events during the quench. It makes a difference. And just because you don't test your airbags by driving your car into a wall doesn't make that a meaningless test.
 
Nathan the Machinist said:
And in these kinds of tests I've been very impressed with properly heat treated Elmax.
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You touch on an excellent point…….Correct heat treat. Whatever steel one chooses the heat treat is critical.

There are far to many knives being made from hi tech steels that are incorrectly heat treated because the maker simply did not follow the manufacturers spec or they do not have the facilities for the correct heat treating procedure.

If you are going to order a hard use knife it pays to ask some probing questions about the heat treating process and subsequent results.
 
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