D2, S30V and M390 sit at three different price points and three different points on the same trade-off curve: how long an edge lasts, how much abuse it takes, and how much care it needs. None of them is “the best.” Each one is the right answer to a different question.
This page explains what actually separates them, which one suits the way you use a knife, and where each steel is a poor choice. If you only want the short version, the table below covers it.
The short answer
| Steel | Best for | Edge holding | Corrosion resistance | Ease of sharpening |
|---|---|---|---|---|
| D2 | Hard-use working knives, value hunters, people who touch up an edge often | High | Moderate — it is not fully stainless | Harder than common stainless |
| S30V | The all-rounder: EDC, camping, hunting, general field use | High | Good | Moderate |
| M390 | Long-use knives where re-sharpening is inconvenient; premium builds | Very high | Very good | Hardest of the three |
If you want one sentence: D2 for value and toughness per dollar, S30V for balance, M390 for maximum edge retention.
What “better steel” actually means
Knife steel is four properties pulling against each other:
- Edge retention — how long the edge keeps cutting before it dulls. Driven mainly by hardness and by hard carbide particles in the steel.
- Toughness — resistance to chipping and cracking under impact or sideways load. Generally falls as hardness rises.
- Corrosion resistance — how well the steel resists rust. Driven by free chromium. More carbon means less free chromium, so the two compete.
- Sharpenability — how quickly a stone restores the edge. High-carbide steels take longer.
Improve one and you usually give up something else. That is why the question is never “which steel is best” but “which trade-off matches how I use this knife.”
One more thing worth knowing before comparing: heat treatment matters as much as the steel name. The same D2 hardened and tempered well will outperform a poorly treated premium steel. Composition tells you the potential; the heat treat decides how much of it you get.
D2: the working steel
D2 is a high-carbon, high-chromium tool steel — roughly 1.5% carbon and 12% chromium. It was developed for industrial dies and cutting tools, which is a good hint about its character: it is built to keep cutting under load.
The chromium content is high enough that D2 is often described as “semi-stainless.” It resists rust far better than a simple carbon steel, but it is not in the same class as a true stainless. Left wet or stored in a damp sheath, it can spot. A wipe-down and a thin film of oil solves this, but it is a habit you have to keep.
Why people like it: edge retention that used to cost far more money, good wear resistance, and a fine-grained edge that responds well to a proper stone. It is also one of the few steels at this performance level that stays affordable.
Where it falls short: it is not the toughest steel around — a very thin, very hard D2 edge can chip if you lever or chop into hard material. And it takes more work to sharpen than 8Cr13MoV or 14C28N, which matters if you are not confident on a stone.
Buy D2 if you want the most cutting performance per dollar, you accept a two-second wipe after use, and you are willing to maintain the edge rather than wait for it to go completely dull.
S30V: the balanced choice
S30V is a particle-metallurgy stainless steel. Instead of casting the steel and rolling it, the alloy is atomized into a powder and then consolidated, which produces a much finer and more evenly distributed carbide structure. The practical result is that the steel behaves consistently across the blade rather than having hard and soft patches.
Its composition — around 1.45% carbon, 14% chromium and 4% vanadium — makes it a genuine stainless with strong edge holding. Vanadium carbides are extremely hard, and they are what give S30V its wear resistance.
Why people like it: it does not force a choice. It holds an edge noticeably longer than common stainless, resists rust well enough to ignore in normal use, and still responds to a normal sharpening routine. For a knife that goes from a pocket to a campsite to a field dressing job, it is hard to argue with.
Where it falls short: it is not the toughest steel at high hardness, and it is not the longest-wearing. It sits deliberately in the middle, which means anyone optimizing hard for one extreme will find it a compromise.
Buy S30V if you want one knife that handles everyday carry and outdoor work without special care or special sharpening equipment.
M390: the long-haul steel
M390 is a third-generation particle-metallurgy stainless, and its composition is unusual: about 1.9% carbon, 20% chromium, 4% vanadium, plus molybdenum and tungsten. That combination produces a very high volume of hard carbides inside a highly corrosion-resistant matrix.
The result is the highest wear resistance of the three, alongside corrosion resistance that holds up in humid, sweaty, coastal or wet conditions. A knife in M390 can go a long time between sharpenings.
Why people like it: edge retention that stays useful through extended use, and a level of rust resistance that removes a maintenance worry. It is a natural fit for a knife that lives in a pocket or a pack for months.
Where it falls short: it is the most demanding of the three to sharpen. The same carbides that resist wear also resist abrasive stones, so restoring a dull M390 edge takes patience and a consistent angle. It is also the most expensive, and on a very thin edge it is not the toughest option.
Buy M390 if you use a knife hard and often, you would rather sharpen rarely, and you are prepared to spend more time on the stone when the day comes — or to have someone else do it properly.
Head to head
| D2 | S30V | M390 | |
|---|---|---|---|
| Family | Tool steel (semi-stainless) | Particle-metallurgy stainless | Particle-metallurgy stainless |
| Carbon | ~1.5% | ~1.45% | ~1.9% |
| Chromium | ~12% | ~14% | ~20% |
| Vanadium | ~1% | ~4% | ~4% |
| Typical working hardness | 58–62 HRC | 58–61 HRC | 59–61 HRC |
| Rust care needed | Yes, light oil | Minimal | Minimal |
| Sharpening effort | Moderate to high | Moderate | High |
| Price tier | Entry | Mid | Premium |
Those composition figures are nominal ranges for the grades, not a specification for any individual knife. Hardness in particular is a choice each maker makes, and it moves performance around within these bands.
Choosing by use, not by spec sheet
Everyday carry
You cut tape, cardboard, packaging and cord. The knife spends most of its life closed. S30V is the sensible default: enough edge retention that you are not sharpening monthly, enough corrosion resistance to ignore pocket humidity. M390 makes sense if you genuinely dislike maintenance. D2 is fine, and cheaper, if you keep it dry.
Camping and hunting
Here the knife meets wood, game, rope and dirt, often while wet, often with cold hands. Toughness starts to matter as much as edge retention. S30V is the safe all-round pick. D2 gives strong cutting performance at a lower price, provided you dry it. A very hard, very thin M390 edge is the least forgiving of the three if the knife gets pried or knocked.
Humid, coastal or saltwater environments
Go stainless, and go high-chromium. M390 and S30V both handle this well. D2 will need attention — rinse with fresh water, dry thoroughly, oil the blade.
If you are new to sharpening
Start with S30V, or with a simpler stainless like 14C28N or 8Cr13MoV. Learning angle control on a steel that rewards you quickly is far more productive than fighting a high-carbide edge on your first attempts.
If it is a gift
A knife that dulls and never gets sharpened is a worse gift than a slightly less exotic one. M390 is the better gift for someone who will look after it; S30V is the better gift for everyone else.
Price: what you are actually paying for
The jump from D2 to S30V buys corrosion resistance and consistency. The jump from S30V to M390 buys wear resistance and a longer service interval. Neither jump buys a sharper knife out of the box — factory edge geometry and grinding quality decide that, and they are independent of the steel.
Spending more on steel while accepting a poor handle, a loose pivot or a badly ground edge is the wrong trade. The steel is one part of the knife.
Care differences in practice
- D2: wipe dry after every use, especially before storage. A drop of oil on the blade once a month is enough. Do not store it in a damp leather sheath.
- S30V: wipe dry, sharpen when it stops slicing cleanly. No routine oiling required.
- M390: rinse and dry after saltwater or heavy sweat exposure, then leave it alone. Touch up on a fine stone or ceramic before the edge is fully dull — restoring a blunted M390 edge is real work.
Frequently asked questions
Is M390 worth the extra money over S30V?
If you use the knife regularly and dislike sharpening, yes. If the knife lives in a drawer and opens boxes twice a week, the difference will not show up in any way you notice.
Does D2 rust?
It can. D2 is semi-stainless: far more resistant than plain carbon steel, less resistant than S30V or M390. Water left on the blade, or storage in a damp sheath, is what causes spotting. Dry it and it is a non-issue.
Which steel holds the best edge?
M390, in wear-resistance terms, followed by S30V, then D2. But a well-treated D2 blade will outcut a poorly treated premium steel, so the maker’s heat treatment matters as much as the grade on the label.
Can I sharpen M390 at home?
Yes, with diamond or high-quality ceramic abrasives and patience. It is not a steel for a cheap pull-through sharpener — that will remove far more metal than it should and leave a rough edge.
Where to look next
Our folding knives are sorted by steel, so you can start from the grade you want. If M390 is the target, the M390 titanium-handle folder and the M390 G10 folder cover two very different carry weights. For S30V, the S30V aluminum-handle model is the mid-range reference. For D2, the carbon fiber D2 drop point is the value pick.
Still deciding on other features? Our folding knife buying guide covers handle materials, lock types, blade shapes and size. If you want a blade that does not fold at all, see fixed blade knives.