M390 is a powder metallurgy martensitic stainless steel developed by Böhler, engineered for extremely high wear resistance combined with strong corrosion resistance. In the knife world, it has earned its reputation for staying sharp for a long time while remaining relatively low-maintenance compared to non-stainless tool steels.
The reason M390 appears so often in premium folding knives and custom knives is simple: many users want maximum edge life without constant worry about rust. By choosing a steel optimized for wear resistance and stainless behavior, we inevitably sacrifice some ease of sharpening and a portion of toughness under extreme abuse. That trade-off defines M390’s personality. It excels in controlled cutting and long sessions on abrasive materials, but it is not meant to be pried, twisted, or slammed through hard impacts. When used as intended, M390 delivers exactly what its design promises.
M390 achieves its performance through a high-alloy recipe centered on carbon, chromium, and strong carbide-forming elements. Typical composition includes about 1.9% carbon, ~20% chromium, ~4% vanadium, with additions of molybdenum and tungsten to refine hardenability and wear resistance.
|
Element |
Content |
Primary Role in M390 |
|
Carbon (C) |
~1.9% |
Enables high hardness and supports carbide formation, forming the backbone of edge retention |
|
Chromium (Cr) |
~20% |
Provides strong corrosion resistance and contributes to stainless steel behavior |
|
Vanadium (V) |
~4.0% |
Forms extremely hard vanadium carbides, driving wear resistance and long edge life |
|
Molybdenum (Mo) |
~1.0% |
Improves hardenability and contributes to corrosion and wear resistance |
|
Tungsten (W) |
~0.6% |
Refines carbide structure and enhances high-temperature stability during heat treatment |
|
Manganese (Mn) |
~0.3% |
Supports hardenability and deoxidation during steelmaking |
|
Silicon (Si) |
~0.7% |
Improves strength and supports deoxidation |
High chromium is what gives M390 its stainless character, while vanadium and tungsten drive the formation of extremely hard carbides that resist abrasion. The engineering trade-off is unavoidable: to gain superior wear resistance and edge retention, the steel becomes more resistant to grinding and sharpening. In practice, that means M390 rewards careful sharpening technique and good abrasives. Compared to simpler stainless steels like N690 or VG-10, it feels more “demanding,” but it repays that effort with longer-lasting sharpness in real use.
Powder metallurgy allows M390 to have a very uniform, fine carbide distribution that would be difficult to achieve with conventional ingot steel. Böhler produces M390 using a PM process that emphasizes micro-cleanliness and structural consistency.
This uniformity improves predictability: blades sharpen more consistently, wear patterns are more even, and performance varies less from batch to batch. The flip side of powder metallurgy is cost and complexity. PM steels are more expensive to produce, which increases knife prices and also accelerates abrasive wear during grinding and sharpening. In other words, by choosing PM for consistency and edge life, we accept higher material cost and higher demands on tools. PM doesn’t make M390 indestructible—it simply makes its performance more repeatable when heat-treated correctly.
With roughly 20% chromium, M390 resists staining and rust far better than non-stainless tool steels. Vanadium forms very hard carbides that slow edge wear during cutting.
Vanadium.
Chromium provides corrosion resistance.
Vanadium is the primary driver of M390’s exceptional wear resistance.
The trade-off is clear: vanadium carbides dramatically increase abrasion resistance, which means sharpening requires harder abrasives and more patience. The flip side of high edge retention is increased demand for diamond or high-quality ceramic stones. Chromium also forms carbides, and in high-alloy steels, this can reduce toughness compared to steels optimized for impact resistance. As a result, M390 thrives in slicing and controlled cutting, not in prying or chopping through knots and nails.
Chromium.
In daily use, M390 is best known for staying sharp through long cutting sessions while resisting corrosion in pockets, kitchens, and humid environments. It excels at cardboard, rope, food prep, and general EDC tasks where abrasion slowly dulls an edge.
The trade-off of this wear-focused design is how the steel fails when overstressed. Instead of rolling, a very thin M390 edge may micro-chip if pushed beyond its comfort zone. That doesn’t make it fragile; it simply means edge geometry and task selection matter. With sensible edge angles and controlled cutting, M390 feels stable and confidence-inspiring. Abuse it, and it will remind you that wear resistance is not the same thing as toughness.
M390 is engineered specifically for high wear resistance, which translates into long-lasting edge retention during abrasive cutting. This is why it’s common in premium EDC knives and even industrial cutting applications.
By choosing M390 for edge life, we inevitably sacrifice sharpening speed. Removing steel takes longer, especially during reprofiling. The practical workaround is simple: maintain the edge with light touch-ups instead of letting it go completely dull. In that scenario, M390 becomes a joy—rarely needing serious work while cutting efficiently day after day.
For everyday carry, M390 is tough enough when paired with appropriate edge geometry. It handles normal cutting, piercing, and utility tasks without issue.
The trade-off appears under impact or lateral stress. Compared to steels designed primarily for toughness, M390 offers less margin for abuse. Tactical knives made from M390 work best when the maker prioritizes stability over extreme hardness. If maximum toughness is your priority, other steels may be better suited. If your priority is long-term cutting performance with stainless convenience, M390 remains a strong contender.
With M390, edge geometry matters more than chasing maximum hardness — a slightly thicker edge often outperforms a razor-thin grind in real use.
M390’s performance depends heavily on heat treatment, not just alloy composition. Böhler specifies controlled austenitizing, quenching, and tempering cycles that can emphasize either corrosion resistance or wear resistance.
By pushing hardness higher, makers can maximize edge retention — but the cost is reduced toughness and a higher risk of micro-chipping on thin edges. By backing off slightly, they gain stability and forgiveness at the expense of some wear resistance. This is the core engineering trade-off of M390: it is highly tunable, but poor heat treatment can undermine its advantages. Two knives labeled “M390” can feel very different in practice.
There is no single “best” hardness for M390; the optimal range depends on grind and intended use. Böhler’s data emphasizes process flexibility rather than one fixed number.
Higher hardness favors slicing longevity, while lower hardness improves edge stability. By choosing one, we inevitably give up part of the other. For EDC knives, many makers aim for a balanced approach that preserves long edge life without making the blade overly brittle. In short, consistent heat treatment matters more than chasing an extreme HRC value.
Böhler’s own specifications and knife-steel references indicate that M390 is generally hardened to about 60–62 HRC. This range balances edge retention, corrosion resistance, and usable toughness in most knives.
|
HRC |
Why |
|
60–62 HRC |
Most production M390 knives aim at this hardness level for a balance of long-lasting edge and reasonable toughness. |
|
~63 HRC |
Some custom heat treatments push up for maximum wear resistance, though higher hardness can reduce toughness. (Noblie) |
|
~59 HRC and below |
Occasionally seen with certain makers or purpose-built blades; generally more forgiving but with slightly less edge retention. |
Cryogenic treatment is used to reduce retained austenite and stabilize M390’s microstructure after quenching. Böhler recommends sub-zero treatment as part of a controlled heat-treat sequence.
The benefit is improved dimensional stability and more predictable performance. The trade-off is added process complexity—cryo is not a shortcut, and it must be followed by proper tempering. Used correctly, it supports consistency; used carelessly, it can push the steel toward brittleness. Cryo is a refinement tool, not a miracle upgrade.
Cryo treatment helps M390 behave consistently, but it can’t fix poor tempering or bad edge geometry.
M390 is often described as difficult to sharpen because it resists abrasion so well. The upside is that it needs sharpening less frequently than many steels.
Maintenance is otherwise straightforward. Thanks to its high chromium content, M390 resists corrosion and staining with basic care. The trade-off is clear: less frequent sharpening, but more demanding sharpening sessions when they do occur. If you accept that bargain, M390 is easy to live with day to day.
The same carbides that give M390 long edge life also resist sharpening abrasives. Soft stones cut slowly, especially during reprofiling.
The flip side of this resistance is predictability. Once you match abrasives and angles to the steel, M390 sharpens consistently. Choosing a polished edge improves push-cut performance but sacrifices bite on fibrous materials; choosing a toothier finish does the opposite. Each choice has a cost, and M390 makes those costs more obvious than simpler steels.
Diamond abrasives are the most efficient way to sharpen and reprofile M390, while ceramics excel for refinement. Angle control is critical.
Due to its high wear resistance, M390 responds best to guided sharpening systems and hard abrasives. This approach delivers consistent results and saves time compared to freehand methods. Systems like TSPROF are often preferred for maintaining control and repeatability with steels of this class.
Do not wait until M390 is completely dull. Small, frequent touch-ups with a fine ceramic honing rod, using very light pressure, can help maintain the edge and reduce the need for heavy resharpening
M390 belongs to the premium stainless PM class, alongside steels like 20CV and CTS-204P. These steels are often treated as near-equivalents, with differences depending more on heat treatment than chemistry.
Compared to simpler stainless steels, M390 offers superior edge retention but demands more from sharpening tools. Compared to toughness-focused steels, it trades impact resistance for wear resistance and corrosion performance. The correct comparison always depends on how you use your knife.
Comparison Table: M390 vs Key Alternatives
|
Steel |
Edge Retention |
Corrosion Resistance |
Toughness |
Sharpening Difficulty |
|
M390 |
Very High |
Very High |
Medium |
High |
|
Elmax |
High |
High |
Medium-High |
Medium |
|
MagnaCut |
High |
Very High |
High |
Medium |
M390 prioritizes wear resistance, while Elmax and MagnaCut emphasize different balances of toughness, corrosion resistance, and sharpenability. Elmax is often chosen for a slightly more forgiving sharpening feel, while MagnaCut is frequently selected for its toughness-corrosion balance.
The trade-off is that steels tuned for balance may not match M390’s edge retention in abrasive cutting. M390 shines when edge life is the primary goal. When versatility or abuse tolerance matters more, alternatives can make sense.
M390 is not ideal for heavy impact, prying, or users who want the easiest sharpening experience possible. By choosing wear resistance and stainless steel behavior, we sacrifice toughness and sharpening speed.
If your knife is a hard-use tool or a budget beater, simpler or tougher steels may offer better value. M390 is best when its strengths—edge retention and corrosion resistance—are actually used.
M390 is worth the price when you value long edge life, stainless steel convenience, and refined cutting performance. It suits premium EDC knives, collectors, and users who cut a lot of abrasive materials.
The trade-off is a higher cost and the need for proper sharpening tools. If you accept that, M390 delivers exactly what it was designed to do. If you don’t, it may feel like overkill. The right answer depends entirely on how and how often you use your knife.
Yes, M390 is a good knife steel when you judge it by what it was built to do: stay sharp for a long time and resist corrosion. In the article’s terms, it’s a wear-resistant and stainless “workhorse” for controlled cutting: EDC slicing, lots of cardboard, rope, day-to-day utility, where edge wear is the real enemy.
By choosing M390 for very high wear resistance, you inevitably sacrifice ease of sharpening and some toughness margin. That trade shows up in two places: it’s slower to process when you need a full resharpening, and a very thin edge can micro-chip if you push it into prying, twisting, or impact-heavy tasks. M390 doesn’t fail mysteriously; it fails predictably when you ask a wear-focused steel to behave like a tough, abuse-tolerant one.
So the honest verdict is simple: M390 is a great cutting steel, not a great abuse steel. If you want a long cutting-edge life plus stainless convenience, and you’re willing to match it with sensible edge geometry, it earns its premium reputation. If your priorities are maximum toughness or “easy sharpening on any stone,” then M390 can be the wrong kind of good.
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