S35VN and MagnaCut are two premium knife steels produced by Crucible Industries using the CPM powder metallurgy process.
Developed by Dr. Larrin Thomas and produced by Crucible Industries, MagnaCut unique alloy composition offers significantly better corrosion resistance and toughness than S35VN stainless steel.
MagnaCut improves upon S35VN which was itself an advancement over S30V steel, by reducing the chromium and vanadium content and adding niobium and nitrogen.
The key difference is MagnaCut’s lack of chromium carbides after heat treatment, leading to its stainless-like corrosion resistance but non-stainless steel toughness levels.
MagnaCut vs S35VN Steel At A Glance
| Property | S35VN Steel | MagnaCut Steel |
|---|---|---|
| Corrosion Resistance | Good but lower than MagnaCut | Excellent – No visible corrosion even after 72 hr salt spray test |
| Toughness | 10-12 ft-lbs in longitudinal testing | 30+ ft-lbs in longitudinal testing, similar to CPM-4V |
| Hardness | Up to 64 HRC based on datasheets | Up to 65 HRC based on testing |
| Edge Retention | 131% of 440C in CATRA testing | 135% of 440C in CATRA testing |
| Ease of Sharpening | More difficult due to coarser vanadium carbides | Easier due to refined carbide structure and lack of chromium carbides |
Corrosion Resistance
Magnacut and S35VN are stainless steels, however, MagnaCut demonstrates noticeably better corrosion resistance compared to S35VN steel.
In a 72-hour corrosion salt spray test, MagnaCut showed no signs of corrosion even at high hardness levels. S35VN exhibited some minor corrosion under the same test conditions.
The improved corrosion resistance of MagnaCut is attributed to its lack of chromium carbides in the microstructure after heat treatment.
S35VN forms some chromium carbides which can deplete the surrounding chromium level.
MagnaCut’s chromium stays in solution which improves corrosion resistance. In electrochemical testing, MagnaCut also demonstrated a higher corrosion potential than S35VN.
While both steels have adequate corrosion resistance for most applications, MagnaCut’s superior performance gives it an advantage in wet environments or when surface perfection is critical.
The combination of high hardness, toughness, and corrosion resistance makes MagnaCut unique among stainless steels, outperforming S35VN in all areas.
Toughness
CPM MagnaCut steel demonstrates superior toughness compared to S35VN in direct impact testing.
With optimized heat treatment, MagnaCut reached toughness values over 30 ft-lbs in longitudinal testing.
This matches or exceeds the toughness of steels like CPM-4V and CPM-M4.
In comparison, direct testing of S35VN by Larrin Thomas showed maximum toughness values around 12 ft-lbs.
The much higher toughness of MagnaCut is attributed to its finer carbide structure and lack of chromium carbides, allowing it to achieve non-stainless toughness levels.
When comparing the two steels at similar hardness levels, MagnaCut retains a significant toughness advantage.
For example, at 62 HRC, MagnaCut had a toughness of 30 ft-lbs while S35VN was only around 10 ft-lbs.
The higher toughness gives MagnaCut better resistance to chipping and edge damage under hard use.
This makes MagnaCut preferable for larger or tougher knives where edge integrity is important.
The combination of high toughness and high hardness in MagnaCut is unique among stainless steels.
Hardness
MagnaCut and S35VN are both powder metallurgy stainless steels but MagnaCut has the potential for higher hardness levels.
According to heat treatment testing, MagnaCut can reach up to 65 Rockwell C hardness with an optimized heat treatment, cryogenic treatment, and appropriate tempering.
In comparison, S35VN datasheets show it is capable of reaching 63-64 Rc at most. This shows MagnaCut reaching 1-2 points higher hardness than S35VN with the same heat treatment parameters.
The ability of MagnaCut to reach hardness levels of 64+ Rc gives it an advantage over S35VN for applications where maximum wear resistance is needed.
The higher hardness potential comes from MagnaCut’s optimized composition and carbide structure to maximize hardness and strength.
Edge Retention
Testing shows that CPM S35VN and MagnaCut steels have comparable edge retention and wear resistance.
In standardized cutting tests, both steels performed similarly, with S35VN rated at 130% of 440C, and MagnaCut at 135% of 440C.
S45VN steel rated at 143% has better edge retention than S35VN steel and MagnaCut steel.
The vanadium and niobium carbides in MagnaCut provide good wear resistance though the overall carbide content is slightly lower than S35VN.
However, MagnaCut knife steel fine carbide structure helps it achieve parity with S35VN steel for edge holding.
In rope cutting tests, knives in both steels achieved similar cut counts before dulling. Direct cutting comparisons by knifemakers found the steels to have very similar edge retention.
The key advantage of MagnaCut is not higher wear resistance compared to S35VN, but its simultaneous improvements in toughness and corrosion resistance.
While matching S35VN in edge retention, MagnaCut exceeds it in other areas.
Ease of Sharpening
MagnaCut has a sharpening advantage over S35VN due to its finer carbide structure.
Knifemakers reported that MagnaCut sharpened easily even on aluminum oxide stones, while S35VN is known to be more difficult to sharpen due to its vanadium carbides.
The fine carbides in MagnaCut are easier to abrade and deburr compared to the slightly larger vanadium carbides present in S35VN.
MagnaCut blade steel was also reported to have excellent feedback and burr removal during sharpening.
While both steels can achieve high sharpness in skilled hands, MagnaCut appears to have an edge in terms of ease and speed of sharpening.
This can be attributed to the refined carbide distribution and lack of coarse chromium carbides. The high hardness capabilities of MagnaCut do not come at the expense of sharpenability.
Final Thoughts on MagnaCut vs S35VN Steel
In my opinion, MagnaCut stainless steel is a clear advancement over S35VN stainless steel for most cutting applications.
The improvements in corrosion resistance and toughness are significant and make MagnaCut stand out from other stainless steels.
CPM S35VN is a well-balanced steel but can’t match MagnaCut’s properties in side-by-side testing.
With comparable edge retention to S35VN, MagnaCut simply outperforms in other areas that matter. The ability to get non-stainless levels of toughness in a stainless package is remarkable.
MagnaCut hits that sweet spot of corrosion resistance, toughness, and wear resistance I look for in a steel.
While S35VN and S45VN will continue serving knifemakers well, I believe MagnaCut represents the future of stainless cutlery steels.
Its combination of attributes makes it one of the most impressive stainless steels I’ve tested and an upgrade over S35VN in every way.