N690 and Its Shelf Neighbours

N690 is a martensitic stainless steel with cobalt, made by Böhler-Uddeholm. In the kitchen world it is less well known than the Japanese grades with the word “gold” in their names, but in European knife production it holds a solid place.

What has been done to it

In composition N690 roughly matches 440C, but it contains more molybdenum plus an addition of cobalt. Hence the nicknames: “Austrian 440C”, “Austrian cobalt stainless”.

Cobalt makes the structure of the alloy uniform. The same purpose is served by rolling the sheet in both the longitudinal and the transverse direction. The practical result: very high corrosion resistance, hardening to 60 HRC, good resistance to impact loads and easy sharpening.

That combination is rare. Normally you pay for chip resistance with edge retention, and for easy sharpening with wear resistance. N690 does not top any single column, but it does not fail in any of them either.

Where you meet it

Mostly in long outdoor blades and tactical knives: where a blade has to hold an edge and also survive impacts, side loads, prying and twisting. Many European firms make knives from it.

In the kitchen it turns up less often, and the logic is the same. Its strong points — corrosion resistance and toughness — matter less on a cutting board than they do in the woods or on a boat.

Neighbours on the shelf

N690 has a crowded neighbourhood of steels with similar compositions, scattered across different national designation systems:

• VG-10 (Japan) — the closest analogue, but with a higher content of molybdenum and chromium;
• AUS-10 (Japan);
• Z100CD17 (France);
• Sandvik 12C27 (Sweden);
• X102CrMo17 (Germany);
• 95Kh18 (Russia).

The reference book this list comes from ends it categorically:

All of them, however, fall short of Böhler N690 in their qualities.

A claim like that should be treated as the opinion of a man who has held those knives, not as the result of measurements. Something else in the list is more useful: one and the same metallurgical idea lives under six different stamps. A buyer choosing between “Austrian” and “Japanese” steel is often choosing between two lines in different standards.

Further along the shelf: the nitrogen steels

Next to them stands a family that went a different way — replacing part of the carbon with nitrogen for the sake of corrosion resistance.

X15TN is a French steel patented by Aubert & Duval. It was developed not for knives but for the medical industry and for jet engine ball bearings. A martensitic stainless with a high nitrogen content, remelted for optimal structure; on paper it corresponds to EN 1.4123 (X40CrMoVN16-2) and UNS42025. Benchmade puts it into saltwater and diving knives.

Cronidur 30, also known as X30CrMoNi15-1, also known as LC200N, Z-FiNit and N360 — depending on who is selling it. A tool steel with a high nitrogen content (about 0.40%), developed in the late 1980s for bearings. Widely used in aerospace; excellent corrosion resistance combined with high toughness even at hardness up to 60 HRC. Spyderco uses it in several models, Henckels in limited-run knives where the price tag goes past 800 euros.

H1, made by the Japanese company Myodo Metals, stands on the same shelf from the other side: it goes into saltwater and diving knives. Benchmade used it and later switched to X15TN.

What this whole shelf has in common

Not one of these steels was created for knives. Bearings, medicine, aviation, tooling — that is their real biography. Knife production is too small for anyone to develop and roll separate grades for its sake; it takes what has already been made for other industries.

The practical conclusion is simple: the properties knife marketing boasts about were most often the requirements of somebody else’s technical specification. The nitrogen in X15TN appeared for the sake of a bearing in an engine, not for the sake of your fish knife. That it also saves the blade from salt water is a happy coincidence, not a design goal.

Who needs this

N690 makes sense where a knife works in the wet and against bone: fish, hunting, a boat, a kitchen in a humid climate. For a domestic cutting board the difference between N690 and VG-10 is mostly on the stamp.

The nitrogen steels are a narrow tool. If your knife does not spend its working day in salt water, paying extra for corrosion resistance buys a property you will never once use.