N690 steel, produced by Böhler, and S35VN steel, manufactured by Crucible Industries, are both knife steels renowned for their durability and specific strengths in different applications.
N690 steel, a variation of 440C, is designed with high chromium content, cobalt, and molybdenum, which enhances its corrosion resistance and ease of sharpening, making it suitable for knives and tools used in harsh, humid environments.
In contrast, S35VN steel, developed through advanced powder metallurgy by Crucible Industries, offers superior toughness and edge retention thanks to its unique combination of vanadium and niobium carbides.
While N690 excels in wear resistance and corrosion protection, S35VN stands out in its ability to withstand heavy-duty use, providing excellent cutting performance and toughness.
N690 vs S35VN Steel At A Glance
| Feature | N690 Steel | S35VN Steel |
|---|---|---|
| Composition | High Chromium (17%), Cobalt, Molybdenum | High Chromium (14%), Vanadium, Niobium |
| Corrosion Resistance | Superior due to high Chromium and Cobalt content | Good, but slightly less than N690 |
| Edge Retention | Slightly lower compared to S35VN | Slightly better due to refined carbide structure |
| Toughness | Good toughness, but less than S35VN | Superior toughness, better resistance to chipping |
| Ease of Sharpening | Easier to sharpen due to simpler carbide structure | More difficult to sharpen due to harder carbides |
| Machinability | Better machinability for manufacturing | Slightly harder to machine due to fine-carbide content |
| Thermal Stability | Moderate, prone to some distortion during heat treatment | Better dimensional stability, less distortion |
| Affordability | More affordable, cost-effective | More expensive due to powder metallurgy and advanced alloys |
| Availability | More common in Europe | More popular in North America |
| Best Use Case | Ideal for general-purpose knives and tools in humid environments | Best for high-performance, heavy-duty tools requiring durability |
Toughness
S35VN demonstrates significantly superior toughness than N690 steel.
S35VN, produced using powder metallurgy, features refined niobium and vanadium carbides, which enhance toughness by reducing brittleness and improving resistance to chipping under impact or lateral forces.
This toughness is evident in transverse Charpy C-notch testing, where S35VN achieves approximately 12 ft-lbs, a notable improvement over conventional stainless steels.
In contrast, N690 steel, while offering reliable toughness due to its cobalt and molybdenum composition, lacks the advanced carbide refinement found in S35VN.
Its toughness is sufficient for standard applications but is comparatively lower in scenarios requiring resilience against high-impact stresses.
Therefore, S35VN is the preferred choice for applications demanding exceptional toughness, such as larger blades or tools subject to heavy-duty use.
Hardness
N690 steel, produced by Böhler, is capable of achieving a Rockwell hardness of approximately 61 HRC under optimal heat treatment conditions.
This is due to its high chromium content, cobalt addition, and molybdenum, which together enhance its hardness while maintaining good wear resistance and corrosion resistance.
On the other hand, S35VN steel, a product of Crucible Industries, can reach a slightly higher peak hardness of up to 64 HRC under specific heat treatment procedures, including cryogenic treatments and double tempering.
Its ability to achieve this hardness is attributed to the presence of vanadium and niobium carbides, which are harder and contribute significantly to the steel’s wear resistance.
Furthermore, its powder metallurgy structure ensures uniform carbide distribution, allowing for optimized hardness without compromising toughness.
Edge Retention
S35VN demonstrates a slight advantage over N690 steel in edge retention due to its refined carbide structure.
S35VN contains a balanced combination of vanadium and niobium carbides, which contribute to its exceptional wear resistance and ability to maintain a sharp edge during prolonged use.
CATRA testing indicates that S35VN achieves approximately 145% edge retention relative to 440C, outperforming N690, which scores lower on similar tests.
While N690 steel benefits from a high chromium content and cobalt addition, which enhance wear resistance, its edge retention falls short compared to the advanced powder metallurgy construction of S35VN.
For applications prioritizing sustained cutting performance and reduced sharpening frequency, S35VN is the superior choice.
Ease of Sharpening
N690 steel offers slightly better ease of sharpening compared to S35VN steel due to its simpler carbide structure and moderate vanadium content.
The fine-grained microstructure of N690, combined with its balanced chromium and cobalt composition, allows for quicker and more efficient edge restoration using standard sharpening tools.
S35VN, while highly durable, incorporates a mix of vanadium and niobium carbides, which increase wear resistance but make sharpening more labor-intensive.
These carbides require advanced abrasives to achieve optimal sharpness, especially after extensive wear.
For users prioritizing ease of maintenance and frequent sharpening, N690 provides a more accessible solution.
Corrosion Resistance
Both N690 and S35VN are stainless steels, however, when evaluating corrosion resistance, N690 steel exhibits slightly superior performance compared to S35VN steel.
N690’s high chromium content, approximately 17%, combined with cobalt and molybdenum, creates a highly corrosion-resistant matrix, making it ideal for environments with high moisture or salt exposure.
In contrast, S35VN features a 14% chromium composition, which, while sufficient for robust corrosion resistance, does not match the level provided by N690.
Additionally, the refined carbide distribution in S35VN prioritizes edge retention and toughness over corrosion resistance, resulting in slightly less protection against pitting and oxidation.
For applications in marine or highly corrosive environments, N690 is the preferred choice due to its enhanced stainless properties.
Machinability
N690 stainless steel and S35VN steel differ in machinability, thermal stability, cost, and availability. N690’s simpler carbide structure enhances machinability, allowing for easier shaping and finishing during production, making it ideal for manufacturers seeking efficiency.
S35VN, with its advanced powder metallurgy design, offers superior thermal stability, reducing distortion and ensuring greater dimensional accuracy during heat treatment.
This makes s35vn stainless steel better suited for high-performance tools exposed to elevated temperatures.
Cost and Availability
Cost is another differentiating factor; N690 is generally more affordable than S35VN, appealing to those balancing performance with budget constraints.
Availability also plays a role, as S35VN is more prevalent in North America, while N690 enjoys greater popularity in Europe.
Considering these additional points provides a more comprehensive understanding of each steel’s unique advantages and potential limitations.
Final Thoughts on N690 vs S35VN Steel
N690 or S35VN? It’s all about your performance and maintenance priorities. N690 is better corrosion resistant, easier to sharpen and more reliable in harsh humid environments.
S35VN has better carbide refinement, slightly better edge retention and durability under heavy use.
In real life an N690 blade resharpened with a whetstone was razor sharp in minutes, so maintenance is a big plus.
Both steels serve different purposes, N690 for general low maintenance use and S35VN for tasks that require durability and sustained cutting performance. Knowing this will help you choose the right steel for your needs.