In 2021, Dr. Larrin Thomas introduced MagnaCut, a steel developed specifically for knives, designed using computational thermodynamics.
Before MagnaCut, M390 was widely used in the super steel category for over a decade, having been developed for industrial applications before being used in blades. Vanax was introduced as a nitrogen-based steel engineered for environments prone to rapid corrosion with conventional stainless steels.
M390 is formulated for high edge retention, using a large carbide volume. MagnaCut is designed to eliminate chromium carbides, increasing toughness while maintaining stainless qualities. Vanax substitutes nitrogen for carbon, resulting in high corrosion resistance with a trade-off in maximum achievable hardness.
Most articles compare these steels individually. Few offer a practical comparison of all three for informed selection.
What Sets MagnaCut, Vanax, and M390 Apart
Why These Three Steels Dominate the Premium Knife Market
Dr. Thomas developed MagnaCut through computational thermodynamics, designing it from the ground up as a knife steel rather than adapting an existing industrial alloy.
Bohler-Uddeholm produces M390, a powder-metallurgy steel originally intended for plastic injection molds that has found widespread adoption in high-end folders. Uddeholm manufactures Vanax, a nitrogen-alloyed steel that offers corrosion resistance on par with that of surgical instruments.
These three steels are considered among the leading options for premium knives. Each offers a different approach to balancing cutting performance, edge retention, corrosion resistance, and durability. Comparing them requires attention to their metallurgical differences.
The Core Tradeoffs Explained
The core tradeoffs between these steels:
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MagnaCut offers the highest toughness, with 8 to 10+ ft-lb in Charpy testing, while maintaining strong corrosion resistance despite lower chromium content.
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M390 prioritizes edge retention through high carbide volume, but has lower toughness and is more prone to microchipping.
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Vanax replaces carbon with nitrogen, delivering exceptional corrosion resistance but limiting hardness to around 60 to 61 HRC.
M390 contains about 22% carbide volume by area, which provides high abrasion resistance in slicing tasks. CATRA edge retention tests show M390 outperforming both competitors. Bohler rates its toughness at 2 out of 5 stars; this low toughness can make thin M390 edges more susceptible to microchipping under impact. Typical hardness ranges from 60 to 64 HRC.
Vanax substitutes nitrogen for carbon, forming fine nitride particles instead of larger carbides. This microstructure provides high corrosion resistance, similar to that of LC200N.
The trade-off is hardness. Vanax maxes out at 60-61 HRC even with cryogenic treatment. It also costs roughly three times as much as S30V and significantly more than either MagnaCut or M390.
Why MagnaCut Outperforms M390 in Corrosion Resistance with Half the Chromium
What “Chromium in Solution” Actually Means for Stainless Steel
The phrase “13% chromium makes steel stainless” appears throughout knife forums and marketing materials. It oversimplifies what actually determines corrosion resistance.
Corrosion resistance depends on the passive chromium oxide layer that forms on the steel’s surface. Only chromium dissolved in the steel matrix contributes to the formation of this layer. Chromium locked inside carbides during heat treatment does nothing to prevent rust. Most stainless knife steels contain 10 to 13% chromium in solution, regardless of total chromium content, because carbide formation consumes the rest.
D2 steel illustrates the problem. It contains 11-12% total chromium, which is close to the stainless threshold. But D2’s high carbon content creates extensive chromium carbides that trap most of that chromium. The result is a steel that rusts readily in humid conditions despite its chromium percentage.
How MagnaCut Achieves Near-Vanax Corrosion Resistance
Dr. Thomas designed MagnaCut to eliminate chromium carbides from the microstructure entirely. The steel uses only vanadium and niobium carbides, which do not consume chromium. With 10.7% total chromium and virtually all of it in solution, MagnaCut achieves corrosion resistance that surprised even its designer.
In Knife Steel Nerds’ testing using 1% saltwater solution, MagnaCut showed no visible corrosion after 72 hours. This performance is comparable to Vanax and LC200N, steels specifically engineered for marine environments. The test results explain why MagnaCut can outperform M390 in corrosion resistance, despite M390 containing nearly twice as much total chromium.
M390’s 20% chromium looks impressive on paper. But roughly 18% of M390’s volume consists of chromium carbides that sequester much of that chromium. More chromium in the alloy does not guarantee more chromium protecting the surface.
Toughness Comparison: Why MagnaCut Resists Chipping Better Than M390
The Myth That High Carbide Volume Equals Better Edge Retention
Knife enthusiasts often conflate carbide volume with edge retention. The reasoning seems intuitive. Harder carbides resist wear, so more carbides should increase wear resistance.
CATRA abrasion testing supports part of this logic. When a blade cuts through standardized abrasive media, M390’s 22% carbide volume outperforms MagnaCut’s lower carbide content. But CATRA measures one specific failure mode: pure abrasive wear against the edge.
Edges fail in other ways. Microchipping occurs when stress concentrations around carbides cause small pieces of the edge to break away. Rolling happens when the edge deforms under lateral pressure. Neither failure mode appears in CATRA testing. In real-world use, they often degrade edge performance more quickly than pure abrasion.
Bohler’s own published data rates M390’s toughness at 2 out of 5 stars. Charpy impact testing quantifies the difference: M390 scores around 3 to 4 foot-pounds while MagnaCut achieves 8 to 10+ foot-pounds at equivalent hardness.
How MagnaCut’s Fine Microstructure Prevents Edge Damage
Carbide size and distribution matter as much as carbide volume. MagnaCut’s vanadium and niobium carbides are smaller and more evenly distributed than M390’s chromium-vanadium carbide mix. Fewer stress concentration points mean fewer initiation sites for microchipping.
This advantage has practical implications. Tougher steel allows thinner edge geometry without fragility. A MagnaCut blade can run a 15-degree edge angle, where an M390 blade might need 20 degrees to avoid chipping. Thinner edges cut more efficiently and feel sharper during use.
When used for breaking down boxes, processing food, or cutting tougher materials, MagnaCut’s edge maintains function over time. The steel resists microchipping, which can degrade M390 edges in similar applications.
When M390’s Edge Retention Advantage Actually Matters
M390 is not an inferior steel. It excels in applications that match its strengths.
Light-to-medium slicing tasks with minimal impact stress favor M390. Opening envelopes, slicing fruit, cutting tape, and precision work involve abrasive wear without significant shock. A gentleman’s folder that sees these tasks exclusively will go longer between sharpenings in M390 than in MagnaCut.
The deciding factor is the use pattern. If your knife primarily slices and rarely impacts hard materials, M390’s carbide structure provides genuine longevity. If your knife sees varied tasks, including occasional abuse, MagnaCut’s balanced properties serve better.
Hardness Selection: What HRC Range to Seek for Each Steel
Why Higher Hardness Is Not Always Better for MagnaCut
The assumption that higher hardness means better heat treatment leads buyers astray with MagnaCut. A 65 HRC blade sounds more impressive than a 60 HRC blade. In practice, the relationship between hardness and performance is more complex.
Dr. Thomas designed MagnaCut to deliver exceptional toughness. At 60 to 61 HRC, the steel achieves this goal, providing roughly 2 to 3 times the toughness of M390 at similar hardness. At 64 HRC, that toughness drops by approximately half. At 65 HRC, MagnaCut’s toughness matches S35VN or Vanax at 60 to 61 HRC.
Pushing MagnaCut to maximum hardness eliminates its primary advantage over other super steels. You end up with a steel that chips more easily, offers only marginal gains in abrasion resistance, and no longer justifies its selection over M390.
For hard-use knives, thin edges, or varied tasks, 60 to 62 HRC best aligns with MagnaCut’s design intent. For light EDC focused on edge retention with minimal impact, 63 to 64 HRC is acceptable. Above 64 HRC, you have undermined the very reason you chose MagnaCut in the first place.
M390 and Vanax Hardness Considerations
M390 runs 60 to 64 HRC in most production knives. Higher hardness increases edge retention in pure slicing but further reduces already-limited toughness. Given M390’s baseline tendency toward microchipping, seeking maximum hardness introduces risk without proportional benefit for most users.
Vanax cannot reach high hardness regardless of heat treatment. Nitrogen contributes less to hardness than carbon, and Vanax tops out at 60 to 61 HRC even with cryogenic processing. This is not a defect or a result of poor heat treatment. It is the physical ceiling for this alloy system.
Buyers should not seek high-hardness Vanax versions, as none exist. The steel’s value lies in corrosion resistance and fine microstructure, not in hardness.
How to Sharpen MagnaCut, M390, and Vanax Steel
Why M390 Resists Conventional Sharpening Stones
M390’s sharpening difficulty stems from basic hardness relationships between abrasives and the steel’s carbides.
Vanadium carbides in M390 are harder than aluminum oxide, the abrasive in most traditional whetstones. When you sharpen on aluminum oxide, the abrasive cannot cut through the carbides efficiently. It can crush them against the steel matrix, but the process feels slow and frustrating. The steel seems to slide on the stone without biting into it.
Diamond and CBN abrasives are harder than vanadium carbides. They shear through the steel’s microstructure rather than fighting it. For M390, diamond plates or CBN wheels are not strictly mandatory, but they are significantly faster and more effective than traditional options.
Why MagnaCut Sharpens Easier Despite Being a Super Steel
MagnaCut’s carbide structure responds differently to sharpening. Its vanadium and niobium carbides are finer and present in lower volume than M390’s carbide mix. The steel performs better on conventional stones than M390.
Knifemakers and users consistently report that MagnaCut sharpens more like a mid-range steel than a super steel. Quality ceramic or glass stones, such as Shapton Glass, produce good results without excessive effort. Diamond stones work faster, but they are not essential for effective sharpening.
For maintenance between full sharpenings, a diamond-loaded strop is efficient and quick. The steel takes a keen edge on conventional systems like the Spyderco Sharpmaker. Users switching from M390 to MagnaCut consistently describe easier sharpening as an immediate benefit.
Sharpening Vanax: The Nitrogen Steel Difference
Vanax’s nitrogen-based microstructure produces extremely fine structures that respond well to most stone types. Users report minimal resistance during sharpening, with the steel taking an edge readily across various abrasive media.
The other factor is its hardness. At 60 to 61 HRC maximum, Vanax is softer than many MagnaCut or M390 configurations. Softer steel requires less aggressive abrasives and less effort to sharpen, regardless of carbide type.
Which Steel Is Best for EDC, Outdoor Use, and Marine Environments?
Best Knife Steel for Everyday Carry and General Use
MagnaCut is a strong choice for EDC due to its versatility across a variety of tasks and conditions.
Tasks such as opening packages, preparing food, cutting cordage, and light prying are within MagnaCut’s capabilities. The steel’s toughness allows for thin edges that cut efficiently, and its corrosion resistance reduces the risk of rust in damp conditions. Sharpening does not require specialized equipment.
For users whose EDC primarily sees light slicing with minimal impact, M390 extends the time between sharpenings. If you open letters, cut tape, and slice fruit without encountering harder materials, M390’s carbide structure provides measurable longevity.
The range of tasks your knife sees often determines the best steel to use. Varied tasks may favor MagnaCut, while predictable, light cutting may favor M390.
Best Knife Steel for Hard Outdoor and Survival Use
MagnaCut performs well in uses that require resistance to impact and stress.
Chopping, batoning, processing game, and outdoor field tasks put edges under greater stress than light cutting. In these scenarios, reliability is often prioritized over maximum edge retention.
Using M390 on large fixed blades introduces a design risk. Impact shock from chopping can cause microchipping or, in extreme cases, catastrophic edge failure. The steel’s low toughness makes it poorly suited to hard use regardless of blade geometry.
MagnaCut’s toughness allows for thinner edge geometry on outdoor knives without compromising durability. Its corrosion resistance also supports performance in field conditions.
Best Knife Steel for Saltwater, Diving, and Marine Use
Vanax justifies its premium in extreme corrosion environments.
Fishing, diving, and constant exposure to saltwater destroy conventional stainless steels within weeks. Vanax’s nitrogen-based nitride structure provides corrosion resistance on par with LC200N and meets surgical instrument standards. A Vanax blade can live in a marine environment without the constant maintenance other steels require.
MagnaCut performs well in humid conditions and occasional saltwater exposure. For a fishing trip or a rainy week in the field, its corrosion resistance is adequate. It is not designed for permanent submersion or continuous salt spray.
If your knife lives on a boat, in a dive kit, or in a commercial fishing environment, Vanax’s higher cost buys genuine durability benefits. For occasional wet conditions, MagnaCut is sufficient and more versatile.
Price, Value, and Steel Availability in 2025
Why Vanax Costs Significantly More Than MagnaCut or M390
Vanax commands a price premium that reflects manufacturing complexity. The steel costs roughly three times as much as S30V and approximately twice as much as Elmax. Nitrogen alloying requires specialized processes that limit which mills can produce it and which heat treaters can work with it.
Fewer knives are available in Vanax, and they consistently cost more than equivalent designs in other steels. For users who genuinely need marine-grade corrosion resistance, this premium is justified by unmatched performance.
For general EDC or outdoor use, MagnaCut offers most of Vanax’s corrosion resistance at a lower cost, with higher toughness and wider availability.
MagnaCut Availability After the Crucible Bankruptcy
Crucible Industries faced financial difficulties in 2024, raising concerns about MagnaCut’s future availability. Erasteel acquired Crucible’s assets and trademarks. Niagara Specialty Metals continues to process and distribute MagnaCut and other CPM steels.
The steel composition, production methods, and quality remain unchanged. Supply chains have stabilized, and knives in MagnaCut are widely available from multiple manufacturers. Buyers should not hesitate based on supply concerns. The steel is being produced and distributed through established channels.
How to Choose Between MagnaCut, Vanax, and M390 for Your EDC
A Decision Matrix Based on Your Primary Use Case
Choose based on your primary use case:
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Choose MagnaCut for balanced performance, varied tasks, and higher toughness.
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Choose M390 for maximum edge retention in light, low-impact cutting.
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Choose Vanax for extreme corrosion resistance in marine environments.
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Choose MagnaCut if you want easier sharpening and lower maintenance.
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Choose MagnaCut if you want the best overall value.
URBAN EDC Knives Featuring Each Steel
Our URBAN F5.5 is available in all three steels, providing a direct comparison within the same blade design. The Jesper Voxnaes design runs identical geometry across configurations, isolating steel performance from handle and blade variables.
MagnaCut configurations, including the F5.5, Chimarra, and Jib, start at $269 to $329 and represent the brand’s most versatile offerings. M390 configurations suit users prioritizing slicing performance over impact resistance. Vanax F5.5 configurations serve those who genuinely need marine-grade corrosion resistance.
Availability varies due to limited weekly drops. New configurations release on Wednesday at 12 pm PT. The choice between steels matters more than the choice between brands. Select the steel that matches your use case and find the design that fits your hand.
Frequently Asked Questions About MagnaCut, Vanax, and M390
Is MagnaCut Really Stainless Steel?
Yes. The arbitrary 13% chromium threshold cited by some sources ignores the distinction between total chromium and chromium in solution. MagnaCut keeps nearly all its 10.7% chromium in solution by eliminating chromium carbides from the microstructure.
Functional corrosion resistance approaches Vanax levels, according to Dr. Thomas’s 72-hour saltwater testing. For practical purposes, treat MagnaCut as stainless. No special rust prevention is required for normal use.
Is M390 Hard to Sharpen Compared to MagnaCut?
M390 is noticeably harder to sharpen. Its vanadium carbides resist aluminum oxide stones, making traditional whetstones slow and frustrating. Diamond or CBN abrasives work faster because they can shear through the carbides rather than fighting them.
MagnaCut’s finer carbide structure makes it significantly more user-friendly on conventional stones. Users switching from M390 to MagnaCut consistently report an immediate, easier sharpening experience.
Why Does MagnaCut Sometimes Chip at High Hardness?
Chipping at high hardness reflects physics, not defects. At 64+ HRC, MagnaCut’s toughness drops significantly, roughly halving compared to 60 HRC. Combined with thin factory edges that may have been overheated during grinding, chipping becomes more likely under use.
The solution is to seek MagnaCut at 60 to 62 HRC for hard use, or to accept the trade-off at higher hardness. User reports indicate that chipping often disappears after sharpening, revealing the factory-ground edge and fresh steel beneath.
Which Steel Should I Buy First If I Am New to Super Steels?
MagnaCut offers the most forgiving combination of properties for learning what super steels can do. It is tough enough to resist chipping during inevitable mistakes, corrosion-resistant enough for low-maintenance carry, and easier to sharpen than most super steels. It handles varied tasks without punishing unpredictable use.
The URBAN F5.5 in MagnaCut at $269 provides an accessible entry point to experience a purpose-designed knife steel without the premium associated with Vanax or the maintenance demands of M390.
