MagnaCut vs 20CV

In the article, “Magnacut vs 20CV” I will compare the properties of these two steels and how their formulation contributes to their performance as knife steels

CPM MagnaCut and CPM 20CV represent two premium powder metallurgy stainless steels that offer an interesting comparison.

MagnaCut was conceptualized and designed by metallurgist Dr. Larrin Thomas but is produced and manufactured by Crucible Industries.

This innovative new steel was created to provide an optimized combination of hardness, edge retention, toughness, and corrosion resistance.

CPM 20CV, on the other hand, has been on the market for a long time and is comparable to popular steels like M390 and CTS 204P. 

While MagnaCut’s steel composition was uniquely engineered to eliminate chromium carbides, 20CV contains a significant portion of these hard, brittle carbides.

MagnaCut vs 20CV Steel Differences At A Glance

Hardness

MagnaCut can achieve significantly higher hardness levels compared to 20CV. According to Crucible data sheets, MagnaCut can reach Rockwell hardness levels of 64+ HRC with cryogenic heat treatment, whereas 20CV is limited to around 59 HRC.

The key difference enabling the higher hardness of MagnaCut is that MagnaCut has a finer carbide structure with smaller vanadium and niobium carbides, whereas 20CV has larger chromium carbides which limits hardness.

MagnaCut knife steel also utilizes an optimized composition and processing to eliminate chromium carbides, resulting in a hardness-boosting combination of high carbon and chromium in solution.

In 20CV knife steel, the chromium is tied up in chromium carbides.

Additionally, the high nitrogen content of CPM MagnaCut further strengthens the steel matrix, enabling higher hardness while 20CV does not contain nitrogen.

This high hardness achieved by steel contributes highly towards knife edge retention and wear resistance.

Toughness

MagnaCut steel has significantly higher toughness compared to 20CV steel due to its refined carbide structure and lower overall carbide content.

According to Crucible data sheets, MagnaCut achieved a Charpy impact toughness value of 38 ft-lbs at 62.5 HRC, whereas 20CV measured only 15 ft-lbs at a lower hardness of 62 HRC.

The main difference enabling the higher toughness of MagnaCut is that MagnaCut has a very fine carbide structure with small vanadium-niobium carbides leading to higher toughness whereas 20CV has larger chromium carbides which lower toughness.

MagnaCut’s composition and processing is also optimized to eliminate brittle chromium carbides, further boosting toughness while 20CV contains significant brittle chromium carbide.

Furthermore, the higher nitrogen content of MagnaCut strengthens the matrix and prevents carbide coarsening, maintaining high toughness in service while 20CV steel lacks Nitrogen in its composition for this benefit.

This high toughness means that knives made from MagnaCut steel can stand high-impact applications without chipping or breaking.

Edge Retention

20CV steel achieves moderately better edge retention compared to MagnaCut steel. According to the CATRA test results from Crucible, 20CV reached 80% cuts more than 440C steel, while MagnaCut achieved 35% more than 440C.

20CV blade steel has a higher overall carbide content at around 18-22%, compared to the 8% carbides in MagnaCut, the higher carbide volume of 20CV provides increased edge retention and high wear resistance.

However, MagnaCut compensates for slightly lower wear resistance with much higher attainable hardness, allowing very acute and stable edges to be used.

So while a 20CV steel knife will give you better edge retention, you will achieve a very thin edge with a Magnacut knife. 

Corrosion Resistance

MagnaCut stainless steel has significantly better corrosion resistance compared to 20CV stainless steel, despite having lower chromium content. 

According to salt spray testing data, MagnaCut showed no signs of corrosion after 72 hours, while 20CV steel exhibited some small spots of corrosion.

The main factor enabling the superior corrosion resistance of MagnaCut is that MagnaCut is designed to eliminate chromium carbides through its composition and processing.

This keeps more chromium in the microstructure to provide corrosion resistance. In contrast, 20CV steel contains significant chromium carbide, which locally depletes the matrix of chromium and creates weak areas prone to corrosion.

MagnaCut can achieve excellent corrosion resistance with only 10.7% chromium, as all of it is in solution. CPM 20CV has higher chromium elements at 20%, but much of it is tied up in carbides.

The high nitrogen content of CPM MagnaCut further enhances corrosion resistance through matrix strengthening while CPM 20CV steel lacks nitrogen.

The innovative design of MagnaCut stainless steel to dissolve chromium carbides provides corrosion resistance exceeding 20CV stainless steel, despite lower chromium content. 

Ease of sharpening

MagnaCut demonstrates easier sharpening and grindability compared to 20CV due to its refined carbide structure and distribution.

According to knifemaker feedback, MagnaCut grinds significantly easier than 20CV. It is reported to have grindability close to non-stainless steels like CPM-4V, despite MagnaCut being stainless.

A factor contributing to the easier grinding of MagnaCut is that MagnaCut has a very fine carbide structure, with small vanadium carbides and niobium carbides. This makes grinding easier compared to the larger chromium carbides in 20CV.

The carbide distribution in MagnaCut is also more uniform than 20CV, leading to less tendency of carbide pull-out during grinding.

In my sharpening experience, I found MagnaCut easier to sharpen and it has a lower burr tendency than 20CV, allowing it to take a keen edge easily. 

These steels are more suitable for EDC pocket knives and folding knives as compared to kitchen knives, they take time to put a sharp edge on them and for this reason, I would recommend 14C28N steel for kitchen knives.

Price

The price of knives made from CPM 20CV are generally about $50 more expensive than MagnaCut steel, this is because 20CV has always been considered as a premium steel and is more comparable to M390 Steel.

MagnaCut on the other hand is a new knife steel that is slowly getting adopted by most knife manufacturers, so its price might rise with time as it becomes highly adopted.

Final Thoughts on MagnaCut vs 20CV

Having used both MagnaCut and 20CV extensively over the past year, I’ve come to appreciate the unique benefits and tradeoffs of each steel.

In my experience, 20CV offers slightly better outright wear resistance and edge retention, likely due to its higher overall carbide content and harder chromium carbides.

The Zero Tolerance 20CV blade I’ve used can take and hold an incredibly sharp edge for impressively long periods.

However, MagnaCut impresses me most with its well-balanced combination of properties. Its innovative composition provides much higher attainable hardness up to 64+ HRC along with excellent toughness.

This enables MagnaCut to use thinner, more acute edges that provide enhanced cutting ability and stability.

With my Hogue Deka MagnaCut blade, I’m able to put an edge that is extremely sharp yet durable. The toughness also gives MagnaCut good chip resistance in hard use.

Additionally, I’ve been very impressed by the corrosion resistance of MagnaCut, exceeding even CPM 20CV steel.

After using my Hogue Deka MagnaCut knife in a humid environment, it showed virtually no pitting.

In terms of sharpening, I can always get my MagnaCut blade scary sharp relatively easily compared to the CPM 20CV blade. 

While 20CV has slightly better wear resistance and edge retention on paper, MagnaCut is a better knife steel for its more well-rounded properties.