S45VN vs MagnaCut Steel

S45VN follows in the lineage of steels like S30V and S35VN which used high chromium for corrosion resistance and vanadium for wear resistance. 

However, metallurgist Dr. Larrin Thomas took a new approach with MagnaCut to eliminate chromium carbides in the microstructure.

This innovative design leads MagnaCut steel to have a combination of properties better than previous stainless steels.

Made using Crucible’s CPM powder metallurgy process, the key difference arises from CPM MagnaCut having only fine vanadium and niobium carbides. 

In contrast, CPM S45VN stainless steel contains significant chromium carbides which reduce its toughness and corrosion resistance. 

Testing shows MagnaCut to have dramatically higher toughness while also achieving higher hardness levels compared to S45VN. 

S45VN vs MagnaCut Steel At A Glance

Toughness

Toughness is the ability of a knife to resist, cracking, chipping, or breaking under impact. MagnaCut steel has significantly higher toughness than S45VN steel. 

In a Longitudinal Charpy C-Notch Testing by Crucible, MagnaCut steel reached toughness values of 38 ft-lbs at 62.5 HRC, whereas S45VN reached around 19 ft-lbs at 61.5 HRC. 

The much greater toughness of MagnaCut is evident when comparing their microstructures.

MagnaCut has a very fine carbide structure with no coarse chromium carbides, leading to its high toughness.

In contrast, S45VN steel has a significant volume of chromium carbides which reduces its toughness.

The superior toughness of MagnaCut makes it more resistant to chipping, allowing the use of thinner and more acute edges without fracture.

This greatly improves cutting ability and edge retention in knives made with MagnaCut compared to S45VN.

Even in chopping knives and other high-impact uses, the toughness advantage of MagnaCut makes it the better performer.

The dramatically higher toughness of MagnaCut compared to S45VN results in better edge stability, edge retention, and cutting ability, making it the superior choice for most knife applications.

Hardness

MagnaCut steel can achieve higher hardness levels than S45VN steel while maintaining excellent toughness and corrosion resistance. 

S45VN can reach hardness up to about 63.5 HRC with optimal heat treatment, while MagnaCut can reach 64+ HRC.

The higher achievable hardness of MagnaCut means it can be used for knives requiring very high strength and edge stability, like Japanese kitchen knives in the 62-64 HRC range.

However, MagnaCut also has much higher toughness than S45VN, even when compared at the same hardness level.

This combination of high hardness potential and excellent toughness in MagnaCut means it is superior to S45VN for most knife applications.

The ability to use thinner edges at higher hardness, without susceptibility to chipping, leads to better cutting ability and edge retention in MagnaCut.

Therefore, MagnaCut offers a better balance of properties and is superior to S45VN for use in knives.

Edge Retention

When comparing edge retention, S45VN and MagnaCut have relatively similar performance in slicing tests like CATRA (Cutlery & Allied Trades Research Association).

S45VN at a hardness of 61.5 HRC is rated at about 140% of 440C steel, while MagnaCut at a hardness of 62.5 HRC is rated at 135% in CATRA testing data by Crucible. 

The two steels have comparable wear resistance, with S45VN steel perhaps slightly better in some tests.

However, MagnaCut steel superior toughness allows for much thinner and more acute edges to be used without fracturing.

This improves cutting ability and real-world edge retention in MagnaCut knives compared to S45VN, despite the similar wear resistance.

The high hardness potential of MagnaCut blade steel also benefits edge stability.

Even though S45VN stainless steel may have slightly better wear resistance in controlled tests.

The ability to use thinner edges with MagnaCut while maintaining toughness means it has better functional edge retention in most real-world cutting scenarios.

Coupled with MagnaCut’s advantages in hardness and toughness, it is the better all-around performer for knives compared to S45VN in terms of edge retention.

Ease of Sharpening

In ease of sharpening, MagnaCut appears to have an advantage over S45VN based on initial testing and feedback from knife makers.

The fine carbide structure of MagnaCut leads to it sharpening relatively easily compared to other high alloy tool steels.

Knifemakers report it sharpens well even on standard abrasives like aluminum oxide stones.

S45VN, with its higher chromium carbide content, does not sharpen quite as easily. 

For most knife users who sharpen their blades, the easier sharpening of MagnaCut gives it an ergonomic advantage over S45VN, allowing sharpness to be restored with less work. 

This makes MagnaCut the better choice for the typical person’s knife usage and maintenance habits.

Corrosion Resistance

MagnaCut and S45VN are stainless steels with excellent corrosion resistance. However, MagnaCut has proven to be surprisingly better than expected, exceeding S45VN steel corrosion resistance. 

Even though S45VN has higher chromium content at 16% vs 10.7% in MagnaCut, the lack of chromium carbides in MagnaCut provides better corrosion resistance.

Testing shows MagnaCut matches or exceeds the performance of premium stainless steels like 20CV and Vanax which are known for their excellent corrosion resistance. 

MagnaCut stainless steel resisted corrosion even in prolonged saltwater spray testing.

In contrast, S45VN exhibits some discoloration and isolated pitting in similar tests.

The higher corrosion resistance of MagnaCut means it can better withstand environmental exposure, acidic foods, and occasional minor surface rust without degradation of the edge.

While S45VN is moderately corrosion resistant, MagnaCut’s superior performance in this area makes it the better all-around choice for knives, especially in demanding environments.

The unexpected corrosion resistance of MagnaCut relative to its composition is a significant advantage over steel like S45VN.

Final Thoughts On S45VN vs MagnaCut

Having experience with both S45VN and the new MagnaCut steel, I’ve found knives made from MagnaCut to be superior in most attributes.

In my testing, MagnaCut achieved higher hardness levels while maintaining dramatically better toughness compared to S45VN, it also showed better than expected corrosion resistance. 

I did not necessarily notice a significant difference in edge retention between the two steels, even though S45VN may have slightly better wear resistance on paper.

However, S45VN is a proven stainless steel that has been used extensively by most knifemakers over the years, so many have mastered its optimal heat treatment to get the best properties.

MagnaCut is still relatively new, so knifemakers are learning how to heat treat it for optimal performance.

This means it’s possible some S45VN knives could outperform MagnaCut in specific areas like edge retention and toughness, depending on heat treatment.

For someone wanting a safe purchase that will certainly not disappoint, S45VN is a good option with its track record and reputation.

But for those interested in trying the latest advancement in stainless steel, MagnaCut offers an excellent combination of properties that can surpass S45VN with proper heat treatment.

I’d recommend getting MagnaCut knives from knifemakers who have experience with this new steel and have mastered bringing out its full potential.

While both are good steels, the design innovations of MagnaCut make it the superior performer in my experience when optimally heat treated.