S90V and S35VN are two premium blade steels developed by Crucible Industries, a leading manufacturer of particle metallurgy (CPM) steels.
S90V, formerly known as CPM 420V, is a martensitic stainless steel that stands out for its high volume of vanadium carbides, contributing to exceptional wear resistance and edge retention.
On the other hand, S35VN is a modification of the popular S30V knife steel, designed to improve toughness and machinability.
Its composition features a reduced vanadium content of 3%, coupled with the addition of 0.5% niobium, resulting in the formation of niobium carbides alongside vanadium carbides.
This unique composition of S35VN enhances toughness and resistance to chipping while maintaining good wear resistance and corrosion resistance similar to S30V.
The key difference between these two CPM stainless steels is S90V excels in edge retention and wear resistance due to its high vanadium content.
While, S35VN offers improved toughness and ease of sharpening over S90V, making it a more suitable option for knives where resistance to chipping and ease of maintenance are paramount.
S35VN vs S90V Steel At A Glance
| Property | S35VN Steel | S90V Steel |
|---|---|---|
| Hardness | Aim hardness: 58-61 HRC, capable of reaching up to 64 HRC | Aim hardness: 56-59 HRC, capable of reaching up to 64 HRC |
| Toughness | Higher toughness than S90V | Lower toughness than S35VN |
| Edge Retention | Good edge retention | Exceptional edge retention better than S35VN |
| Corrosion Resistance | Comparable corrosion resistance | Comparable corrosion resistance |
| Grindability/Sharpening | Easier to grind and sharpen due to reduced | More difficult to grind and sharpen |
| Key Feature | Improved toughness and machinability over S30V | High volume of vanadium carbides for exceptional wear resistance |
Hardness
Crucible data sheet for S90V recommends an aim hardness of 56-59 HRC, while the data sheet for S35VN suggests an aim hardness of 58-61 HRC.
However, with proper heat treatment S90V and S35VN can reach up to 64 HRC.
Higher hardness of these knife steels makes them more suitable for applications that require superior wear resistance and edge retention in knives.
Toughness
Toughness is the measure of a knife steel to resist chipping or breaking under impact. According to Crucible S35VN steel exhibits higher toughness compared to S90V steel.
In a Transverse Charpy C-notch Toughness Testing, S35VN achieves around 12 ft-lbs of Toughness, while S90V achieves lower toughness values of around 2.5 ft-lbs.
The higher toughness of S35VN makes it more resistant to chipping and breaking, especially in larger knives that may encounter side loading or impact forces.
This improved toughness in S35VN is attributed to its modified chemistry, where the vanadium content is reduced and replaced with 0.5% niobium.
The presence of niobium carbides, along with vanadium and chromium carbides, contributes to the enhanced toughness of S35VN compared to the high volume of harder vanadium carbides in S90V.
Edge Retention
CPM S90V steel exhibits superior edge retention and wear resistance compared to S35VN steel.
The CATRA (Cutlery & Allied Trades Research Association) testing data shows that S90V has an edge retention of 145% relative to 440C stainless steel.
A CATRA study by Bohler-Uddeholm on S35VN found its edge retention to be around 132%-140% of 440C.
The exceptional edge retention of S90V steel is attributed to its high volume of hard vanadium carbides, formed due to its high vanadium content of 9% and reduced chromium content of 14%.
These hard vanadium carbides provide superior wear resistance compared to chromium carbides found in higher amounts in other stainless steels like 440C.
The outstanding edge retention of S90V makes it an excellent choice for knives that require extended periods of use without frequent sharpening, such as hunting knives.
Corrosion Resistance
Both S90V and S35VN are stainless steels, designed to offer a comparable level of corrosion resistance suitable for most knife applications.
When it comes to corrosion resistance, neither steel has a clear advantage over the other, as their performance.
The corrosion resistance of S90V steel is primarily derived from its 14% chromium content, which allows the formation of a protective passive oxide layer.
Additionally, the presence of 1% molybdenum in S90V contributes to enhancing its resistance to pitting corrosion.
On the other hand, S35VN steel’s corrosion resistance benefits from a higher chromium content of 14%, combined with 2% molybdenum.
The increased molybdenum content in S35VN further improves its resistance to pitting and crevice corrosion, potentially giving it a slight edge over S90V in certain corrosive environments.
While corrosion test data suggests that S35VN may exhibit marginally better corrosion resistance than S90V, the difference is relatively small.
The choice between these two steels for corrosion resistance alone may not be a significant factor, as their performance in this aspect is comparable.
Ease of Sharpening
S35VN steel has better grindability and is easier to sharpen compared to S90V steel.
Due to the high vanadium carbide content in S90V, its machinability and grindability will be slightly more difficult than other steels like D2 or 440C.
In contrast, CPM S35VN is much easier to machine than S90V steel and easier to machine than S30V.
The superior grindability of S35VN can be attributed to its modified composition, where the vanadium content is reduced and partially replaced with niobium carbides.
These niobium carbides, with the lower volume of vanadium carbides, make S35VN more machinable and easier to grind than the high volume of hard vanadium carbides present in S90V.
The harder vanadium carbides in S90V can lead to increased wear on abrasives and make the sharpening process more time-consuming and challenging.
However, it is important to note that S90V’s superior wear resistance may compensate for the more challenging sharpening process by requiring less frequent sharpening over time.
Final Thoughts S35VN vs S90V Steel
In conclusion, having experienced both S90V and S35VN steels firsthand, I can confidently say that S35VN is a more well-rounded balance for most knifemakers and enthusiasts.
While S90V boasts exceptional edge retention due to its high volume of hard vanadium carbides, it comes at the cost of reduced toughness and increased difficulty in sharpening and grinding.
S35VN, on the other hand, offers an improvement over S90V in terms of toughness and ease of sharpening, thanks to its modified composition.
The presence of niobium carbides, along with vanadium and chromium carbides, in S35VN enhances its resistance to chipping and breaking, making it a more suitable choice for most knives.
Additionally, the slightly lower wear resistance compared to S90V is often a reasonable trade-off for the improved grindability and ease of maintenance that S35VN provides.
While S90V’s wicked edge retention is undeniably impressive, I would only recommend it to experienced knife enthusiasts who have the skills and patience to sharpen it.
For beginners or those seeking a more user-friendly experience, S35VN is an excellent option that combines high wear resistance with better toughness and sharpening ease.