“Toughness, edge retention, corrosion resistance—pick two.” Is this still the case today?

Deino said:
Wear resistance is generally about hardness. Most metals by themselves, including iron, are quite soft. The hardness comes from the amount of cementite and crystal structure formed using carbon (carbide) or other elements. Nevertheless, the harder they get, the more brittle they become. Cast iron is extremely high carbon (by steel standard) iron alloy, it is hard, but can't be used to make blade as the edge will break into small dust easily, due to the tiny chipping.
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Wear resistance has more to do with carbides than hardness. The reason wear resistance and toughness are on opposite sides of the scale is because as you add to wear resistance with carbide volume, you are also adding weak points in the steel matrix that are more prone to break and crack leading to chips etc.

Hardness can add to edge stability to a point, but also reduces toughness.

This is my understanding anyway.
 
chalby said:
Wear resistance has more to do with carbides than hardness. The reason wear resistance and toughness are on opposite sides of the scale is because as you add to wear resistance with carbide volume, you are also adding weak points in the steel matrix that are more prone to break and crack leading to chips etc.

Hardness can add to edge stability to a point, but also reduces toughness.

This is my understanding anyway.
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Carbides are what create the hardness in steel most of the time, no? Vanadium carbide and Wolfram carbide are harder than Chromium carbide, hence they have more wear resistance and the alloys using them have higher usable hardness.
And if the high carbides steel is not heat treated to the hardness (more to do with heat if I'm not wrong, but still all related) where the carbides form, they are not better than "lower grade" steels.

Edit: Nvm, I remembered the Blue Super... super hard, but low wear...
 
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The hardness of the carbides matters for wear resistance. But you can have a steel with lots of vanadium carbide heat treated anywhere between 30 and 63+ Rc so the hardness of the carbides and the steel are not the same thing.
 
Bkicks333 said:
If I can’t sharpen it in the field with the basics I’m not really interested.
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That’s why there’s nothing wrong with the old proven ones like 1095 and 5160, IMO. Not the best performance by modern standards sure, but they’re sturdy and reliable. As long as I keep them oiled and away from water, I never had any major corrosion issues.

Not cool when knife companies overprice them though. 😅
 
DangerZone98 said:
That’s why there’s nothing wrong with the old proven ones like 1095 and 5160, IMO. Not the best performance by modern standards sure, but they’re sturdy and reliable. As long as I keep them oiled and away from water, I never had any major corrosion issues.

Not cool when knife companies overprice them though. 😅
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I remember wanting the latest and greatest super steels until it came time to sharpen in a pinch 😂 After a few bad experiences I’m with you and prefer the simplicity of a nice carbon steel for an actual user. It’s still fun to use some 110v to cut paper and hairs at the office though… what a flip flop🔪
 
My knives mostly see light duty so I don't need crazy edge retention. It's nice to have extra but decent is acceptable to me. Corrosion resistance is mostly a seasonal concern but I appreciate a high hedge. Honestly, I could be okay with 14C28N for the rest of my life.

Since we are blessed with options, Elmax strikes an attractive balance on the higher end. I'm interested in S45VN but haven't seen a knife I love in it yet. Following the story, appreciating Larrin Larrin 's goal, and being fascinated by the chemistry; I was very excited about MagnaCut. Now I have some and I'm glad to use it. Of course, it's splashed into an already huge EDC rotation and that's another thing. When my knives are competing to get carried once a week, high edge retention can border on infinite edge retention. 😜
 
I value high toughness with good edge retention most. If heat treat is good, some of the simpler tough carbon steels such as 80crv2 or 5160 well done provide me with more than adequate edge retention. I like the convenience of a steel being stainless but it comes after the other 2.
 
1095 works just fine for me, and I work my knives hard. Ease of sharpening in the field is a big factor for me.
 
Officer's Match said:
I don't claim to have the knowledge/education/background of the maker of that graph, but I find (from my own experience) it extremely dubious to claim - as the graph does - that M390 is equal in "toughness" to 154CM.
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You think M390 might be even worse?
 
Larrin said:
You think M390 might be even worse?
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I have found 154CM to be pretty tough, especially compared to M390. I have to screw up pretty bad to chip 154CM, whereas I have seen plenty of chipped edges in M390. Don't get me wrong, I love both for their particular set of attributes, but my experience with both puts them fairly far apart in toughness (and edge retention for that matter).
 
The Cedric & Ada charts rate M390 a 6 for toughness and 154CM a 5. I do not know how that testing was done.
docs.google.com

Cedric and Ada Steel Comparison Ratings

Graphs @dropdown 413 edge retention tests with 112 different materials 261 knives from 100 makers 121 Worksharp edges (20 degree) 115 KME edges 68 Factory edges 109 other edges (Tormek, Edge Pro, stones, or sharpened by others)
docs.google.com docs.google.com
 
I remember when NASA introduced their disastrous "faster, better, cheaper" motto, forgetting to properly quantify those things when making motto a priority for engineers to work with. You can certainly focus hard on one, but even when you focus on getting the most of two you're starting to lose the higher end possibilities. Like a lot of things in this life, design and material choice mostly comes down to specialization and compromise. You have need of something that is great for n, but now you need to measure how much compromise you're willing to accept in other facets of performance.

We're at a point now in material science, where you can order materials to purpose, instead of being always forced to plug and play with what's available. The problem is that unless you have material scientists on the payroll and have some pretty deep pockets, you're still going to have to compromise at some point. I might be able to get a knife material that would do all three, better than anything else on the market, but that knife might also cost $30 million each and possibly require that I wear protective gear to avoid getting cancer from even occasional handling. You could continue sparking a super steel arms race, even more than what we've seen in the last decades, if the knife industry employed more material scientists and funded research. At some point though, there has to be the business realization that the vast majority of knife sales are still going to be gas station knives and budget blades.
 
jstn said:
I’d say no. I guess it depends on how much of each property you need, but something like Cruwear has a good balance. Good edge retention, pretty tough, and decent corrosion resistance. I value well- rounded steels in my collection, and Larrin’s Magnacut has supplanted all else for me. It’s plenty tough for anything I do with a knife, I find the edge retention to be very good, and I haven’t gotten it to stain even when trying to do so on purpose. For folders and small fixed blades, it’s as perfect as it gets imo, at least until Larrin comes up with something else lol. Plus, it’s really not hard to sharpen, even at 63-64 hrc.

After my first few Magnacut blades, the composition of my collection underwent an overhaul. I sold most of my knives and started tracking down comparable knives in MagnaCut. I’ve been very pleased. I don’t know that I’d want a sword made of Magnacut (though Dawson makes them), but I have no use for a sword anyway.
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Curious as to whose magnacut you've tested and were pleased with? I am looking forward to trying some magnacut but here of companies running it soft and getting average results 👎🏻
 
Another Shepherd said:
The Cedric & Ada charts rate M390 a 6 for toughness and 154CM a 5. I do not know how that testing was done.
docs.google.com

Cedric and Ada Steel Comparison Ratings

Graphs @dropdown 413 edge retention tests with 112 different materials 261 knives from 100 makers 121 Worksharp edges (20 degree) 115 KME edges 68 Factory edges 109 other edges (Tormek, Edge Pro, stones, or sharpened by others)
docs.google.com docs.google.com
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Well, certainly others far more qualified than myself have had different results. I suppose other factors (particularly HT) are involved.
 
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