Have you ever come across knives made from a cobalt-vanadium stainless steel called N690 (N690CO) from Bohler? Have you ever wondered, “Is N690 steel good for knives?”
Well, I was in such a situation, so I decided to get some information about it, the things that are just interesting to know about a steel and crucial for a knife purchase. Things like: the chemical composition of the steel, the hardness, whether it is stainless or a stainless steel, and so on.
Table of Contents
What is Bohler N690 steel?
Bohler N690 steel is a stainless, martensitic chromium steel with cobalt, molybdenum and vanadium additions from the Austrian company Voestalpine Bohler Edelstahl GmbH & Co KG. This high-carbon steel is suitable for hardened tools and components with very high hardness and high edge retention.
We can mention knife blades, surgical cutting instruments, disc knives for the meat industry, corrosion-resistant rolling bearings, valve needles and pistons for refrigeration machines, and scale blades and pans.
Other designations and standards of N690 steel
“N690CO steel” is also available alternatively under these designations:
| Standard specifications | Proprietary equivalents |
|---|---|
| DIN X105CrCoMo18-2 | Panzer36 |
| W-Nr 1.4528 | Aichi ZA-18 |
| Bohler-Uddeholm N692 | |
| Bohler-Uddeholm N690 ISOEXTRA | |
| Lohmann LO-R 4528 |
Bohler N690 steel chemical composition
| Element | Portion | Effect |
| Chromium | 17.30% | Improves wear resistance, heat resistance and scale resistance. It increases tensile strength because it acts as a carbide former. Use of rust-free or stainless steel, as it increases corrosion resistance from a mass proportion of 12.2%. Reduction in weldability. |
| Cobalt | 1.50% | Improve hot hardness, corrosion and wear resistance. Increase in tensile strength and yield strength, but at the expense of toughness. carbide former. |
| Carbon | 1.07% | Increasing hardness and tensile strength. In larger quantities, increase in brittleness and reduction in forgeability and weldability. |
| Manganese | 0.40% | Improves hardness and tensile strength. |
| Molybdenum | 1.10% | Improves hardenability, tensile strength and weldability. Reduction in forgeability and ductility. |
| Silicon | 0.40% | Improves strength. |
| Vanadium | 0.10% | Increasing hardness, increasing wear resistance and improving tempering resistance. |
Bohler N690 steel has a high carbon, chromium and molybdenum content, providing a balance between hardness and toughness.
Is Bohler N690 steel stainless steel? Is it rustproof?
Yes, Bohler N690 is stainless steel because its sulfur and phosphorus content (so-called iron companions) does not exceed 0.025% (see here).
It is also a rust-free steel because it contains 17% chromium and is free of the so-called iron companions phosphorus and sulfur. To be considered rust-free, it must contain a chromium content of at least 10.5 – 13%, depending on the definition, which must be dissolved in the austenite or ferrite.
What is the hardness of Bohler N690 steel?
The hardness of Bohler N690 steel is typically around 58-61 HRC (Rockwell hardness scale). Its high hardness level also makes it resistant to corrosion and wear, making it a popular choice for outdoor and tactical applications. If properly heat-treated and maintained, Bohler N690 can be a reliable and long-lasting option for a variety of cutting needs.
Properties of N690CO steel
What is the performance of N690Co steel in areas such as edge retention, corrosion resistance, toughness, sharpenability, etc.? Let’s take a look.
Edge retention
Due to its hardness, blades made of N690 steel hold their edge very well. The ability to maintain a sharp edge for long periods of time means that a knife is made of N690CO steel. You can use these knives for a long time without having to re-sharpen them. This also makes it a suitable material for outdoor knives.
Corrosion resistance
This is one area where N690CO excels, with a chromium content of 17.3% – far more than the 12.2% required for a stainless steel! I can assure you that Böhler steel will not be damaged by extreme humidity, moisture, or salty/corrosive environments. In other words, an N690CO knife can be used in all conditions without any problems.
Wear resistance
N690co steel has high wear resistance due to the presence of chromium and vanadium. It is also close to “premium” steels and can be used for a long time until it is visibly worn.
Sharpening
N690CO has very good edge retention and the edge stays sharp for quite a long time. However, this does not mean that it will not become duller over time. When it comes time to sharpen an N690CO blade, this will tend to be a rather easy undertaking.
This sets it apart from other hard steels where sharpening takes a lot of time. As a rule of thumb, steels up to 60 HRC are comparatively easy to sharpen, from 60 HRC upwards it takes significantly more perseverance or the use of better tools such as diamond grinding stones or the use of machines.
Machinability
N690CO steel contains molybdenum in its chemical composition, which improves machinability. This means that relatively little force is needed to cut the steel and obtain a good surface finish. In addition, the wear on the machine tools used is comparatively low.
Toughness
Normally, no conventional steel grade that has good toughness is also very hard, as these properties are contradictory. However, this steel is an exception. While N690CO does not offer superior toughness, it does offer good enough toughness to be used outdoors to prevent splintering and breakage, such as in “batoning” – splitting wood with a knife as a splitting wedge and a wooden paddle to drive it into the wood.
My opinion: Is N690 steel good for knives?
A knife made of N690 steel offers excellent edge retention, excellent corrosion resistance, good toughness and wear resistance, so the answer is clearly YES.
N690 steel is an excellent knife steel, especially for hunters, anglers, fishermen and anyone who is out in nature. Bohler N690 holds sharpness well, does not rust, and at the same time is comparatively easy to sharpen, which makes it predestined for a knife for skinning animals, for example.
The Bohler N690 steel will also work well for chefs and divers. However, you have to keep in mind that this is a high-end steel, so a knife made of Bohler N690 may seem a bit overpriced.
Bohler N690 steel equivalent
Since Bohler N690 is a high-end steel with a balanced chemical composition that features edge retention, hardness, toughness, and wear resistance, the steel that probably comes closest to it would be VG10 stainless steel. Both offer excellent properties for hunting, kitchen and fishing knives and are in roughly the same price range.
N690 in direct comparison with other steels
I have compared N690 steel with some similar steels to make it easier for you to choose from:
N690 vs S30V steel
| Criteria | Bohler N690 | CPM S30V |
| Edge retention | 3/10 | 5/10 |
| Simplicity of sharpening | 7/10 | 5/10 |
| Corrosion resistance | 7/10 | 7/10 |
| Toughness | 6/10 | 6/10 |
S30V is very close to N690 in terms of corrosion resistance and toughness but offers better edge retention.
N690 vs VG10 steel
| Criteria | Bohler N690 | VG10 |
| Edge retention | 3/10 | 5/10 |
| Simplicity of sharpening | 7/10 | 6/10 |
| Corrosion resistance | 7/10 | 7/10 |
| Toughness | 6/10 | 4/10 |
Compared to N690, VG10 offers equal corrosion resistance with lower toughness and higher edge retention.
N690 steel vs M390
| Criteria | Bohler N690 | M390 |
| Edge retention | 3/10 | 8/10 |
| Simplicity of sharpening | 7/10 | 5/10 |
| Corrosion resistance | 7/10 | 8/10 |
| Toughness | 6/10 | 6/10 |
M390 offers better edge retention, better corrosion resistance and the same toughness as N690, but is more difficult to sharpen.
Difference between N690 and N690CO steel
When searching for information on N690 steel, sooner or later you will also stumble upon a steel called N690CO. You may ask – what is the difference?
In short, there is none. N690 = N690CO as you can see from the chemical composition on the manufacturer’s page. The appended “CO” simply stands for the cobalt (CO) content. The designation N690CO seems to be widespread, especially in the English-speaking world, as a designation for this steel.
Conclusion: Is Bohler N690 steel a good knife steel?
To be honest, I have always been a fan of Bohler (formerly known as Bohler Uddeholm, now as Voestalpine Bohler Edelstahl GmbH & Co KG) and am even more so now – not least because of their extremely interesting company history.
N690 is pretty much always used for premium and high-end knives, as its composition provides an extremely good balance of its properties. A knife made of Bohler N690 steel will stay sharp for a very long time.
And if it becomes dull, it is still comparatively easy to sharpen with conventional watered whetstones. At the same time, the high chrome content guarantees a flawless blade without stains. Clear buy recommendation!
