S35VN is a martensitic stainless steel, developed from S30V by reducing vanadium content and adding niobium.
This gives S35VN improved toughness and machinability over its parent steel for increased resistance to chipping and edge rolling.
The key difference is that S35VN emphasizes on achieving a balance of good edge retention, and corrosion resistance, while CPM 3V optimizes for incredibly high toughness, and wear resistance.
This makes 3V well-suited for larger, more robust knives where impact toughness is prioritized, though it lacks stainless properties.
CPM 3V vs S35VN Steel At A Glance
| Property | CPM 3V Steel | S35VN Steel |
|---|---|---|
| Hardness (HRC) | 58-64 | 58-61 |
| Toughness (Charpy Impact) | Excellent better than S35VN | Lower than 3V, Better than S30V |
| Edge retention | Similar to D2 steel, it is lower than S35VN | Better than CPM 3V (higher carbide content) |
| Corrosion Resistance | Non stainless steel | Stainless steel, Better than 3V steel |
| Ease of Sharpening | More difficult due to high vanadium carbides | Easier due to finer carbide content and improved machinability |
Hardness
S35VN and CPM 3V have different hardness capabilities that impact their performance as knife steels.
CPM 3V data sheet shows it can achieve hardness levels of 58-60 HRC and the ability to reach at least 64 HRC with higher austenitizing temperatures.
In comparison, the recommended heat treatment for S35VN targets the 58-61 HRC hardness range.
The similar higher achievable hardness of both steels should theoretically provide better edge retention and wear resistance.
Toughness
CPM 3V exhibits higher toughness than S35VN steel, though S35VN reaches toughness levels better than most stainless steels.
Charpy C notch impact toughness shows CPM 3V steel achieving an impact toughness of 85 ft-lbs at 58HRC, S35VN on the other hand was able to achieve an impact toughness of around 28ft at 60HRC.
CPM 3V is noted to have impact toughness approaching that of shock-resistant tool steels like S7, which can exceed 85 ft-lbs at 57 HRC.
CPM 3V steel toughness is in the range of highly tough stainless knife steels like 420HC and 14C28N stainless steel.
So while S35VN was designed with improved toughness over S30V as a goal, CPM 3V exceeds it in impact resistance.
Edge Retention
CPM S35VN Steel has better edge retention capability than CPM 3V steel.
The higher edge-holding ability of S35VN can be attributed to its overall carbide content stemming from its high carbon and vanadium levels in the steel composition.
CATRA edge retention show that S35VN achieves a value of around 40% better than 440C, 3V steel on the other hand is about 35% better than 440C steel.
On the other hand, CPM 3V has wear resistance, similar to that of D2 steel.
CPM 3V derives its wear resistance primarily from the vanadium carbides, and S35VN contains a combined total of hard vanadium and niobium carbides improving its wear resistance.
The greater volume percentage of these highly wear-resistant metallic carbides gives S35VN the edge over CPM 3V in resisting abrasion and retaining a keen cutting edge longer.
Corrosion Resistance
Regarding corrosion resistance, S35VN holds a clear advantage over CPM 3V for use in knives.
S35VN is a stainless steel containing 14% chromium, S35VN exhibits good corrosion resistance, rated at 7.8 out of 10 based on testing data, this puts it on par with premium stainless knife steels like Elmax.
In contrast, CPM 3V is not considered a stainless steel, containing only 7.5% chromium which provides limited corrosion protection, on par with CruWear steel.
The superior corrosion resistance of S35VN makes it much more suitable for knives that may see wet environments or will need increased protection against staining, pitting, and rust.
CPM 3V’s lack of stainless properties means it requires blade maintenance and cleaning to prevent corrosion and staining.
For knives intended for heavy outdoor use, food prep, kitchen duties or anywhere increased moisture and acids are present, the stainless capabilities of S35VN are highly advantageous over CPM 3V.
Ease of Sharpening
The volume of hard vanadium carbides in CPM 3V steel makes it more difficult to sharpen than S35VN.
These very hard carbides increase overall wear resistance, which is great for edge retention, but also increases abrasion resistance during sharpening.
S35VN has a finer overall carbide content (3.5% VC + NbC), which translates to slightly easier sharpening.
Additionally, the S35VN data sheet notes it was designed to have improved machinability over S30V, from which it was derived.
Improved machinability often correlates with better grindability and sharpening characteristics for S35VN steel.
Final thoughts on 3V vs S35VN Steel
In conclusion, both S35VN and CPM 3V steels from Crucible Industries offer excellent performance for knives, but with distinct strengths.
CPM 3V alloy composition gives it truly outstanding toughness, which makes it well-suited for blades where maximum toughness is the top priority like batoning knives.
S35VN, on the other hand, provides a more well-rounded combination of good edge retention, and stainless corrosion protection that CPM 3V lacks.
My personal experience with S35VN over the years has been awesome it is an all-around blade steel that I would highly recommend to anyone.
When it comes to hard use knives like bushcraft where impact toughness is crucial, CPM 3V certainly has the required toughness, but S35VN beats it by providing better corrosion resistance.