We have to get over this thing about super steels because there has been one around for ages but no one wants to know about it.
When it comes to marketing, the knife world could win hands down. Well maybe a close competitor would be marketing connected to car sales or the mobile phone industry. However, the world of knife marketing has something which neither of the aforementioned has, and that is it is driven mostly by the consumers who are all that is needed to market the brands they quest after. In other words they convince themselves they must have it and what they are buying is the best because it is the hardest toughest meanest (just joking) knife steel out there. forget applications, just worry about the edge and how to sharpen it LOL!
Ok all jokes aside!
Let me explain.
There are 2 basic categories when it comes to cutting blades: 1) Industrial Purposes, and 2) non industrial.
Let's talk about food.
Cutting implements produced for sole purpose of cutting food to be directly consumed.
A) Non Industrial usage, for which many of us are familiar with, for example domestic home usage.
Domestic Usage , ie cutting tools for the purpose of direct eating, for example one's knives (of the knife and fork routine) for those who use a knife and fork-remember many do not). As far as latest and greatest knife steels for this sector, it's a done deal as pretty much 18/8 stainless steel has been the choice for countless years due to ease of manufacture and the relatively cheapness of the raw materials, plus the longevity and durability over generations. There is simply no need to introduce anything more complicated, it works, as it satisfies all of the consumers requirements including final finish and yes, dishwasher safe!
There is a slight cross over between home usage use in the Commercial Kitchen/Restaurant/Cafe. In the latter case, slightly higher grades of high carbon stainless steels and or carbon blades start to appear, however basically the dominant knife steel grades are those of high chromium and ease of resharpening. The important thing to remember is that these are areas of high product abuse.
Also note here it's not just about steel compositions and hardness it's more about being made "food safe" in terms of design and that means dishwasher proof against harsh corrosive high alkaline detergents.
B) Industrial (2 categories)
(i) Cutting blades for the food processing industry.
This is an industry where blades must perform vast numbers of repetitive actions without failure and where the steel must also satisfy the requirements of food safety. These steels must have a good balance between high corrosion resistance (often the environment is "wet" and be able to maintain an almost service free cutting edge. Here we start to see higher grades of steels being used such as but not limited to: the 200, 300 and 400 grade stainless steels, with the 400 series producing longer lasting cutting edges. All of these grades must make the food grade standards ie not to leach any contaminants into the food being processed. There are of course international standards in place that need to be satisfied in order to allow one to manufacture cutting implements that can be used with food. For example: EC 1935/2004 for European standards. ISO 22000 Food safety management, this is a global food safety management standard. GB 4806 is the Chinese standard for within China. These are but several standards in regards to standards for food cutting implements.
(ii) Steels developed for industrial cutting and high hardness wear resistance applications. (no food stuffs involved).
These are steels used to cut any material other than food items. The properties of these steels (hence the cutting edge) are the following: resistance to: impact; corrosion resistance, high hardness, high hardness at high temperature operation without loss of temper; high durability, ie high toughness; relatively cost effective dependent upon the tooling applications and the end products.
High hardness applications which do not involve cutting implements such a bearing production.
It is the above industry which has driven the development of new knife steels as we know it and it is this same industry where the majority of metallurgical research and development has and is occurring.
I purposefully include the above table because a certain knife steel notably 440C which had it's origins in industry especially in the bearing world, made it's way into the general public as this super knife steel, highly resistant to corrosion and able to maintain a very good edge. It made a huge appearance in the scuba diving world with countless dive knives being manufactured with it. A high carbon, high chromium "new" knife steel was introduced which had been around for ages in the industrial world.
Today 440C is still around in the knife world and despite what many would tell you, 440C is still an excellent knife steel for many reasons, those reasons proven countless times within industry. Of course there has been a plethora of other knife steels developed since the 1960's. I can remember as a kid in Australia 440C being touted a great knife steel back in the mid 70's!
Since then, as mentioned above, there have been many "new" knife steels introduced with probably the next "great knife steel" was ATS 34 developed by Hitachi in Japan,
which featured approximately X5 the amount of Mo compared with that of 440C and hence making the steel tougher and hence knives being able to be made harder than HRC 59 eg ATS-34 and retain good toughness of which can be reliably hardened up to 60-61 HRC.
Two other knife steels in common usage throughout the general public, have both "migrated", you guessed it, from industry, they are of course D2 (12% C, sometimes erroneously referred to as a "semi stainless steel")
Air hardening D2, a proven knife steel
[and variations such as K340 (8%Cr)- actually 8%Cr is WAYless than 12% Cr] and N690 (stainless high Cobalt, high Chromium).
Now D2 needs no introduction other than to say it is a commonly used steel for the production of dies and cutting tools and despite it's "common" ranking amongst knife aficionados, also makes for an excellent outdoor knife steel. The same is for K340 with a relatively recent introduction to the outdoor knife world (circa 2016 where Russian companies were pioneering the use of this steel outside of industrial processing). Today, we see companies such as Halfbreed Blades using the same premium ISO DUR version of K340
K340 ISO DUR is manufactured using an electro slag process
(Halfbreed Blades- if you ever read this please please make some models uncoated, K340 is ok not coated!)
as their "GEN 2" versions of their military and outdoor knife production. In fact for this company the majority of their products are manufactured with K340 ISO DUR.
Some other tool steels
Another popular tools steel today is Japanese made SK 85, a tools steel with exceptional edge holding capacity and can be tempered as flexible as a sword (check products by Work Tuff Gear!)
Tools steels rock, don't be a snob, they are industry proven!
N690 stainless tool steel, is also in common usage in the knife world, especially from the main players in the Italian knife manufacturing scene; a steel which as mentioned made it's debut in industrial milling tools where milling tools needed to be developed with high hardness retention under high temperature without the loss of temper.
N690 also at home in the woods (when it's wet LOL).
N690 also has superior corrosion resistance to the chloride ion and excellent edge retention and can be easily sharpened. It is a stainless steel perfectly suited to harsh wet/humid environments which can be commonly encountered in out of doors applications.
We must remember it IS the Operating Environment which should dictate the knife steel choice for the consumer and not hardness alone, the latter which seems to be obsessed over in a fanatical way by many.
Fast forward to today for another example of specialist treatment and innovations in metallurgical processes we have Nitro X7,
New technologies, new ways of making steels with ESR and above atmospheric ESR are changing the way we look at Nitrogen as an alloying element in knife steels.
a steel which although not produced by the super precise methods of powder metallurgical steel production, yet shows a microstructure comparable if not better than some PM steels!
3V a classic "early" (almost 30 years ago) Powder steel formulation
Classic V3 Powder metallurgical Steel Do I really see a difference in sharpness retention compared with non Powder steels? Answer: No not really and BTW Benchmade were heat treating (to a far greater HRC) way above what Crucible were recommending for 3V!
Nitro X7 (a stainless steel)which can be reliably heat treated to HRC 63!
Nitro X7 builds upon much metallurgical research into the controlled introduction of the element Nitrogen into the steel alloy and retention during and after ingot production.
Nitro X7 the new (proven) kid on the block
Now if we are still not satisfied with a HRC of 63, let us now turn to yet another industry standard high speed milling steel, and that is S600 or M2 and similar. S600 has been a "go to" choice in industry for many years.
S600 has the following properties:
Exceptional wear resistance
High hardness (possible for >HRC 64!)
High thermal stability (ok not so important for outdoor knives)
Ability to withstand high mechanical loads
High resistance to abrasion
High resistance to pressure, deformation and fatigue.
What is S600?
It is a W-Mo-V high speed tool steel commonly used throughout the oil and gas industry.
Let's see what the product manufacturer has to say:
Dirty bark a test for all knife steels
Some basic data regarding S600
"industrial knives", "machine knife","special cutting tools" "twist drills and taps".
Where am I heading here? Well it's clear that certainly based upon industry usage and what's on paper, S600 appears to be a rather excellent choice for those seeking a long lasting (as in super sharp) high Rockwell hardness steel without a brittle edge.
Serious outdoor knives also need a good geometry
Ok so now to meat of this article!
Here's the deal, just the facts. I think I'm probably the ONLY guy who regularly tests knives and outdoor products across the globe.
YES, that's right, across the globe, because my real daytime job (which has about zero to do with outdoor products) allows me to do so, ie travel across both hemispheres and this is clearly (at least to my mind and my astute followers-if there are still any left LOL) shown in the varying environments seen in my videos on https://www.youtube.com/@BushCampingTools
So that being said, I can test products on all sorts of vegetation (dead or alive) under varying different environments to see how do they really hold up. What is comfortable at minus 10C and what is comfortable at plus 30C?; Is it corrosion proof in super high humidity of the jungle or salt spray?
Does it hold an edge after working both northern hemisphere hardwoods and then later southern hemisphere hardwoods? Both northern and Southern hemisphere species are challenge for any knife edge. How long does a knife edge last when working in such natural environments?
Knife testers (on youtube as apposed to "entertainers" for example the Dutch Bushcraft "boys" -their words not mine) solely performing tests indoors do so (I would hope so) to attempt to mitigate the vast variability of the wilds and provide some sort of semi pseudo scientific evidence of the stability of a knife edge.
However, no one is cutting reams of A4 paper, nor kilometres of hemp ropes etc. etc. in the wilds. Nor is ANYONE smashing through a car chassis either.
During real usage knife edges are contacting dirt, rocks, and countless hard objects in the super variable wilds. The thin edges are exposed to chloride ions from sweat and salt spray to food acids and blood and guts, bone, skin, fish scales, dirt impregnated bark et. etc. Knife edges are dragged sideways etc. etc.
Knife users too, during real usage, are not standing by an ergonomic bench or table but could be in any position (or with wet greasy hands), so that handle comfort and ergonomics will definitely play key roles in how useful that knife is to them regardless of the steel but more about geometry of the entire construction.
So in all of these real world adventures with knives, certainly a steel which I have still yet to seriously* sharpen is that on my S600 ONTOS II from the Italian company Extrema Ratio.
Now let's be clear here, it is NOT my go to knife for working in very humid or wet conditions despite the excellent blade coating however all of that being said I personally find little rusting if any along the actual knife edge (the only exposed raw steel surface).
An S600 knife is one you can bash away with, chop away with, hack away with and cut like no tomorrow, simply without the need to resharpen the blade for very long periods in the field. But an S600 knife is not for you if you are lazy and let your knives go blunt before resharpening, because at HRC 64 you will be really putting in the time.
I would choose a blade with more Chromium in solid solution for higher corrosive environments. That being said, wet environments doesn't stop S600 being used in the oil and gas industries. Besides that, one is supposed to clean off their blades after use in the field LOL!
BCT
* I mean sit down with gear probably not intended for field use and spend at least one hour at the job- or even with non bench sharpening tools spend at least 30 minutes on the knife edge.
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