M398 Steel Guide: Composition, Performance, Heat Treatment and Knife Use

M398 is one of the most wear-resistant stainless steels used in premium knives today. It is not a general-purpose “best steel for everything.” It is a high-carbide powder metallurgy steel designed for long edge life, strong stainless behavior, and excellent abrasive wear resistance. In a knife, that makes M398 especially interesting for collectors and EDC users who value edge retention more than impact toughness.

For a buyer, the short version is simple: M398 can be excellent in a refined custom knife, especially a premium folder with thin, controlled cutting geometry. It is less suitable for chopping, prying, batoning, abusive outdoor use, or very thin edges used recklessly. If you want to see M398 used in current premium production-custom folders, browse our Herman Knives category, where selected Bartosz Herman models use M398 alongside MagnaCut, M390, RWL34 and Damasteel.

What Is M398 Steel?

Böhler M398 MICROCLEAN is a powder metallurgy, corrosion-resistant martensitic chromium steel with very high wear resistance. It was developed as a high-performance stainless tool steel, and its official application range includes industrial wear applications as well as custom hand knives. In knife terms, M398 is best understood as a stainless, high-carbon, high-vanadium evolution of the M390 family pushed further toward wear resistance.

That design choice matters. M398 is not chosen because it is easy to sharpen, exceptionally tough, or ideal for rough impact work. It is chosen because it can hold a working edge for a very long time when the blade is used within its intended envelope: slicing, draw cuts, controlled EDC work, cardboard, packaging, rope, light food prep, and collector-grade folding knives where edge stability and clean geometry matter.

For broader steel context, compare this guide with our knife steel chart.

M398 Steel Composition

The official Böhler composition shows why M398 behaves the way it does. It carries very high carbon and very high vanadium for a stainless steel, while keeping chromium at approximately 20%. The result is a large carbide volume: excellent wear resistance, but reduced toughness.

Carbon, Chromium, Vanadium, Molybdenum and Tungsten

The key numbers are carbon, chromium and vanadium. Carbon at 2.70% is extremely high for a stainless knife steel. Chromium at 20% keeps M398 in the stainless category, although much of that chromium is tied up in carbides rather than freely available for corrosion resistance. Vanadium at 7.20% is the biggest practical difference from M390: it increases hard vanadium carbide content and pushes M398 toward more wear resistance.

Molybdenum and tungsten are present at lower levels, but they still matter. In a knife blade, they help the heat-treat response and contribute to the high-performance tool-steel character of the alloy. They are secondary players compared with carbon, chromium and vanadium, but they are part of what makes M398 more than a simple high-chromium stainless steel.

What the Alloy Design Means in a Knife Blade

The alloy design tells you the honest story before the knife is even built. M398 wants to cut abrasive material for a long time. It does not want shock loading, twisting cuts, chopping into knots, prying, or extremely acute edges used against hard media. A good maker can tune geometry and heat treatment, but no maker can make M398 behave like a tough low-carbide steel.

How M398 Steel Is Made

M398 is made by powder metallurgy. In simplified terms, the molten alloy is atomized into powder, consolidated, and processed into steel stock. This route produces a finer and more controlled structure than conventional ingot steel would normally allow at such high alloy content.

Powder Metallurgy Explained

Powder metallurgy matters because high-alloy steels form many carbides. In conventional steelmaking, those carbides can become large and unevenly distributed. Powder metallurgy helps control segregation and improves consistency. For a knife, that means better grindability, more predictable heat treatment, and a more usable high-wear steel than an equivalent composition made by older ingot methods.

That does not mean M398 has tiny carbides compared with every modern knife steel. Knife Steel Nerds testing found that M398 has coarse carbide structure for a powder metallurgy steel, especially compared with steels that achieve similar edge retention through a different carbide strategy. This is one reason M398’s toughness is limited even though it is a PM steel.

Why Carbide Distribution Matters

Carbides are the hard particles that provide much of M398’s wear resistance. The more and harder carbides a steel contains, the longer it can resist abrasive dulling. But carbides are also harder and more brittle than the surrounding steel matrix. If they are large or clustered, they can reduce toughness and make very thin edges more vulnerable to microchipping.

In practice, this is why M398 should be paired with sensible edge geometry. A thin slicing grind is appropriate. A recklessly thin edge with a very low angle can become fragile. For more on how edge shape changes cutting behavior, see our guide to knife grinds and our article on knife sharpening angles.

M398 Steel Performance

M398 is a specialized steel. It performs extremely well in wear resistance and edge retention, reasonably well in corrosion resistance, and poorly in toughness compared with more balanced modern steels.

Edge Retention

Edge retention is M398’s strongest argument. In controlled testing by Knife Steel Nerds, M398 showed excellent CATRA edge retention and slightly higher edge retention than S90V after accounting for hardness, though below S125V. In practical use, this means a well-made M398 folder can keep cutting long after many more balanced steels need maintenance.

Toughness

Toughness is the weak point. M398 contains a very high carbide volume, and that hurts resistance to chipping and fracture. This does not make M398 “bad.” It means M398 must be used honestly. It belongs in controlled cutting tools, not in abusive survival knives.

Corrosion Resistance

M398 is stainless and has very good corrosion resistance. Knife Steel Nerds saltwater testing found M398 roughly comparable to 20CV/M390 and S110V in that test, and clearly better than S90V, S125V and S60V. Still, stainless does not mean stain-proof. Saltwater, sweat, blood, citrus, and wet leather storage can still mark a blade if ignored.

Wear Resistance

Wear resistance is very high because of the steel’s carbon, vanadium and chromium carbide structure. This is the same reason M398 performs well in abrasive cutting but resists sharpening. M398 is a steel for users who prefer sharpening less often and are willing to sharpen more carefully when the time comes.

Sharpening Difficulty

M398 is not a beginner sharpening steel. Standard aluminum oxide stones can be slow because vanadium carbides are harder than aluminum oxide abrasive. Diamond or CBN stones are the right choice. The goal is not to make the edge excessively polished; for many EDC uses, a clean medium-fine diamond finish will preserve bite better than a mirror polish.

M398 Steel Hardness and Heat Treatment

Most knife buyers will encounter M398 somewhere around the low-to-mid 60s HRC, depending on the maker and heat treatment. The exact hardness is less important than the full heat-treat recipe: austenitizing temperature, quench method, cryogenic treatment, tempering, retained austenite control, and final edge geometry.

Typical Knife Hardness Range

For knives, M398 commonly makes sense around 61–64 HRC. At the lower end, the blade may gain a little more tolerance and ease of deburring. At the higher end, it can maximize edge holding but may become even less forgiving. For a thin premium folder, I prefer a maker who balances hardness with edge geometry rather than simply chasing the highest Rockwell number.

Why Heat Treatment Changes Real-World Performance

Heat treatment controls more than hardness. It affects retained austenite, carbide dissolution, corrosion resistance, deburring behavior and edge stability. Two knives marked “M398” can behave differently if one has a cleaner heat treatment and more appropriate geometry.

Thin Edges, Chipping Risk and Edge Geometry

M398 can support excellent slicing geometry, but there is a limit. The more acute the edge, the more careful the user must be. If the knife is used for plastic clamshell packaging, cardboard, rope and food prep, a thinner edge can be excellent. If the user twists the edge through hard plastic, staples, bone, knots or wire, M398 can chip where a tougher steel might roll or survive.

M398 vs M390 Steel

M398 and M390 are related in performance philosophy, but they are not the same steel. M390 is the more balanced premium stainless steel. M398 is the more wear-resistant, more specialized version. The biggest composition difference is vanadium: official Böhler data lists M390 at 4.00% vanadium and M398 at 7.20% vanadium.

Which Holds an Edge Longer?

M398 usually holds an edge longer in abrasive cutting because it has higher carbide volume and more vanadium than M390. For cardboard, synthetic cord, packaging and similar media, that advantage is real.

Which Is Tougher?

M390 is the tougher and more balanced choice. M398 sacrifices toughness for wear resistance. If the knife will see impact, twisting cuts or rough outdoor use, M390 is generally a safer choice.

Which Is Better for EDC?

For most EDC users, M390 is easier to recommend. For an experienced user who wants maximum edge life in a premium folder and understands sharpening, M398 can be the more interesting steel.

M398 vs MagnaCut

M398 and MagnaCut solve different problems. M398 is a high-wear stainless steel. MagnaCut is a highly balanced knife steel designed to combine stainless behavior, toughness and edge retention without chromium carbide in the heat-treated microstructure.

Wear Resistance vs Toughness Balance

M398 wins on wear resistance and likely long abrasive edge retention. MagnaCut wins strongly on toughness balance. For a knife that may be used harder, MagnaCut is the safer steel. For a collector-grade folder used mainly for clean cutting, M398 offers a more specialized edge-retention profile.

Corrosion Resistance and Practical Use

MagnaCut has an excellent corrosion-resistance design because chromium is not tied up in chromium carbides in the same way. M398 still has very good corrosion resistance, but it achieves its performance through a much heavier carbide structure. In humid, saltwater or sweat-heavy use, MagnaCut is generally easier to trust with less maintenance.

M398 vs S90V, S110V and ZDP-189

M398 belongs in the same discussion as high-wear stainless steels such as S90V, S110V and ZDP-189, but it is not automatically superior to all of them. Knife Steel Nerds testing places M398 in the high-edge-retention stainless category, with excellent wear resistance but weak toughness-edge retention balance compared with S90V and S110V.

Where M398 Fits Among High-Wear Stainless Steels

M398 fits near the top of stainless knife steels for wear resistance. Its issue is not edge retention; its issue is balance. It is a premium steel for buyers who know exactly why they want it. It is not the ideal answer for users who want one steel for every knife job.

Best Uses for M398 Knife Steel

M398 is best used where controlled cutting and premium construction matter more than abuse tolerance.

EDC Folders

M398 is well suited to premium pocket knives and high-end folders. A folder is normally used for slicing, packaging, cord, light food, and daily utility cuts. That is M398 territory.

Collector Knives

M398 is attractive in collector knives because it adds a technical performance story to premium finishing, titanium handles, inlays, engraving and exact-piece craftsmanship. Collectors often value both the steel choice and the maker’s execution.

Light Cutting Tools

For light cutting tools, M398 makes sense when the user wants minimal sharpening intervals. It is excellent for abrasive slicing, but not for impacts.

When to Avoid M398

Avoid M398 if the knife will be used as a camp chopper, pry bar, baton, rough field tool, rescue wedge, or hard-use fixed blade. For those roles, look at tougher steels and thicker edge geometry. If you are choosing a heavy-duty outdoor knife, start with our fixed blade knife guide instead.

Pros and Cons of M398 Steel

Is M398 Steel Good?

Yes, M398 is good steel if you want what it is designed to provide: very high wear resistance, long edge retention, stainless behavior, and premium technical appeal. It is not good if you expect toughness equal to MagnaCut, CruWear, 3V or other tougher knife steels.

My practical verdict: M398 is a specialist steel for refined cutting tools. In a premium folder from a maker who understands heat treatment and edge geometry, it can be excellent. In a survival knife or abusive outdoor blade, I would choose something tougher.

FAQ About M398 Steel

Is M398 better than M390?

M398 is better than M390 for maximum wear resistance and long edge retention. M390 is better as a balanced EDC steel because it is generally tougher and easier to live with.

Does M398 steel rust?

M398 is stainless and has very good corrosion resistance, but it can still stain or corrode if neglected in saltwater, sweat, blood, acidic residue, or wet storage. Clean and dry the blade after use.

Is M398 hard to sharpen?

Yes. M398 is hard to sharpen compared with more balanced steels because of its high wear resistance and vanadium carbide content. Use diamond or CBN stones, keep the angle consistent, and do not wait until the knife is completely dull.

Is M398 good for hard-use knives?

No. M398 is not my choice for hard-use knives. It is a high-wear cutting steel, not a high-toughness abuse steel. For hard use, prioritize toughness, blade thickness, heat treatment, and geometry.

What hardness is best for M398 knives?

Many knife applications make sense around 61–64 HRC, depending on heat treatment and geometry. For most users, a clean heat treatment and stable edge matter more than chasing the highest possible Rockwell number.

Is M398 a premium knife steel?

Yes. M398 is a premium powder metallurgy stainless steel. It is found in high-end knives because it offers unusual wear resistance, modern metallurgy, and collector appeal. It should still be judged by the maker’s heat treatment, grind, edge angle and overall knife design.

Author: Aleks Nemtcev | Knifemaker with 10+ Years of Experience | Connect with me on LinkedIn | Follow me on Reddit

References

• Böhler / voestalpine: M398 MICROCLEAN official product data
• Böhler: M390 MICROCLEAN official product data
• Niagara Specialty Metals: CPM MagnaCut data sheet
• Knife Steel Nerds: M398 steel testing — edge retention, toughness and corrosion resistance
• Knife Steel Nerds: knife steels rated by toughness, edge retention and corrosion resistance