N690 steel, often referred to as Böhler N690 or N690Co, is a European stainless steel developed by Böhler-Uddeholm in Austria. It combines respectable hardness and wear properties with excellent corrosion resistance. Over time, N690 has gained widespread popularity among custom knifemakers and mid-tier production brands due to its balanced performance. In particular, it is often viewed as a more affordable alternative to higher-end powder-metallurgy steels while still delivering strong edge retention and reliability.
Although it is not as modern as certain high-vanadium or powder-metallurgy steels, N690’s proven track record and consistent manufacturing quality have secured its place in the knife industry. Some enthusiasts compare it to VG-10 (a Japanese stainless steel) because both contain cobalt and share similar hardness potentials along with corrosion resistance. N690’s versatility keeps it relevant for applications ranging from folding everyday carry (EDC) knives to outdoor fixed blades.
N690 typically contains the following approximate elemental composition:
Because its chromium content exceeds 10.5%, N690 is categorized as a stainless steel. Chromium forms carbides and a protective oxide layer, both of which contribute to corrosion resistance. Here are the primary roles of the key elements:
N690 responds well to various heat treatments, showing a consistent microstructure. Knife blades made from N690 typically display very good corrosion resistance, good toughness, reliable edge retention, and comparatively easy sharpening.
Knife makers who choose to hot-forge N690 generally work within a temperature range of about 1050–1150 °C (1922–2102 °F). This makes the steel malleable for shaping under hammer and anvil. Key considerations:
Although cold forging of stainless steels is not common in traditional blade-making, some specialized operations or minor adjustments (like straightening or surface texturing) may occur at or near room temperature. Because cold work can introduce cracking or stress in the steel, it’s generally done sparingly and with caution.
N690 is commonly austenitized between about 1050–1100 °C (1922–2012 °F). The higher end of this range dissolves more carbides, allowing for increased hardness but potentially reducing overall toughness.
After reaching the desired austenitizing temperature, quenching options vary:
Like many stainless steels, N690 typically undergoes at least two tempering cycles. Tempering temperatures often range from 180–300 °C (356–572 °F), depending on the target hardness and intended application. Below is a simplified table showing a general relationship between tempering temperature and achievable hardness (HRC):
| Tempering Temperature (°C) | Approx. Hardness (HRC) |
|---|---|
| 180 | 60–61 |
| 200 | 59–60 |
| 220 | 58–59 |
| 250 | 57–58 |
| 300 | 56–57 |
Cryogenic treatments (e.g., subzero or liquid nitrogen quenching) between austenitizing and tempering can further refine the grain structure and provide a slight boost in wear resistance or hardness. However, for most practical knife applications, N690’s performance gains from cryo are modest compared to those seen in high-vanadium steels.
N690 is highly corrosion-resistant, thanks to its elevated chromium content. Compared to lower-chromium tool steels (like D2) or carbon steels (like 1095), N690 generally stands up well to moisture and even mildly salty or acidic conditions. It isn’t impervious to rust in extremely harsh environments, but routine care such as wiping the blade after use typically suffices to keep it stain-free.
In the realm of stainless steels, N690 displays good toughness. While not as tough as some lower-alloy or specialized steels (e.g., 5160 or CPM-3V), it handles most normal impacts, chopping, and stress well—especially with correct heat treatments. Cryogenic treatments or triple tempering can further optimize its toughness.
One of N690’s prime attractions is its respectable edge retention. The mix of moderate carbon, chrome, and cobalt ensures it holds a sharp edge for a good length of time. It may not surpass high-vanadium steels like CPM-S90V in raw wear resistance, but it provides a comfortable middle ground that many users find adequate.
Compared to some premium powder-metallurgy steels, N690 is considerably more forgiving. Standard whetstones, ceramic rods, or diamond sharpeners can restore an edge effectively without requiring excessive time or specialized equipment. This combination of decent edge-holding and straightforward sharpening is a key reason it remains a staple in the knife community.
Because of its reliable corrosion resistance and good toughness, N690 is well-suited for bushcraft or camping knives. It tolerates exposure to water, soil, and varying temperatures without corroding excessively, making it popular for outdoor enthusiasts who need dependable performance.
Blades used for field dressing or skinning benefit from stainless steels that handle contact with blood and other fluids. N690’s high stain resistance and ability to maintain a sharp edge through multiple tasks make it a solid choice for hunting knives.
EDC knives often require a balance of edge retention, corrosion resistance, and ease of maintenance. N690 fits nicely into this category, hence its presence in many folding knife designs—especially from European manufacturers like Fox Knives and Böker.
For those seeking extreme edge retention or wear resistance found in high-vanadium or exotic powder-metallurgy steels (e.g., CPM-S90V, K390), N690 may not hit the absolute top tier. However, it compensates with more manageable sharpening demands and generally lower cost, making it a strong compromise for most routine or even heavy-duty knife tasks.
While N690 is stainless and highly resistant to rust:
Such simple upkeep helps preserve the knife’s appearance and performance over time.
N690 generally occupies a mid-level price point. It’s more expensive than entry-level steels like 8Cr13MoV or AUS-8, but less costly than high-end powder-metallurgy steels such as M390 or CPM-S45VN. For enthusiasts or makers seeking a stainless steel that balances corrosion resistance, edge retention, toughness, and ease of sharpening at a reasonable cost, N690 offers excellent value.
Numerous European manufacturers have embraced N690 for their knife lines:
In summary, N690’s enduring reputation arises from its well-rounded metallurgical profile and user-friendly characteristics:
Although it may not match the extreme wear resistance or toughness of the most specialized and expensive steels, N690 handily meets the practical needs of most knife users. Its mid-priced market position and reliable production quality make it a favorite among both custom builders and mainstream brands, ensuring N690 remains a go-to stainless steel for real-world cutting applications.
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