We independently evaluate all recommended products and services. Any products or services put forward appear in no particular order. If you click on links we provide, we may receive compensation.
S90V and M390 offer a clear tradeoff: S90V has higher abrasive edge retention, while M390 has higher corrosion resistance. Their toughness ratings are equal. Choose S90V when wear during long slicing sessions is the priority; consider M390 when damp carry and easier rust care matter more.
Performance Ratings
For the science, we turn to Dr. Larrin Thomas of Knife Steel Nerds, who has kindly allowed us to share his ratings here.
| Property | CPM S90V | Böhler M390 |
|---|---|---|
| Abrasive edge retention | ||
| Toughness | ||
| Corrosion resistance |
Heat treatment, hardness and geometry affect actual knives.
S90V Is the Wear-Focused Choice
S90V rates 9 for abrasive edge retention and M390 6.5. That is the main reason to pick S90V for a knife used heavily on abrasive material. The difference is not a claim that it cuts a fixed percentage longer in every task.
Niagara’s S90V datasheet identifies its high volume of vanadium carbides as a contributor to wear resistance. For the owner, the useful question is whether cutting regularly wears the edge down enough to make that extra resistance worthwhile.
Our S90V steel profile explains its emphasis on wear resistance.
M390 for a Wetter Carry Routine
M390 rates 9 for corrosion resistance and S90V 7.5. Both are stainless, but M390 has the advantage in this framework when moisture is part of daily use. That can matter for a pocket knife exposed to sweat or one used for food as well as packaging.
Keep either blade clean and dry after use. A high score is not permission to leave salt or food residue on it, and the table does not estimate how long a blade can remain wet before rust appears.
See the M390 steel profile for a closer look at its stainless properties.
There Is No Toughness Winner in These Ratings
Both steels rate 3.5 for toughness. We would not describe M390 as the tougher alternative to S90V based on these scores. If resistance to chipping is your main concern, this pair does not offer a rated advantage in either direction.
Check the edge geometry of the knives you are considering. A thicker edge may tolerate more stress but cut less freely; that design choice is separate from the equal material ratings.
Include Sharpening Equipment in the Decision
S90V’s high wear resistance is useful during cutting and relevant when repairing an edge. Diamond or cubic boron nitride (CBN) abrasives are practical options for both steels, particularly S90V’s hard vanadium carbides. Neither rating translates directly into minutes at the sharpener.
We would choose S90V for sustained abrasive slicing when its maintenance fits the owner’s setup. We would lean toward M390 for mixed everyday use where corrosion resistance has more practical value. If both requirements are modest, the knife’s ergonomics and price can settle the decision.
Composition
Our steel composition guide explains what the elements do and how to read these values.
CPM S90V: Niagara typical composition, mass %; selected elements, not a batch analysis. Niagara Specialty Metals: CPM S90V.
Böhler M390: Böhler average composition, mass %; selected elements, not a batch analysis. Böhler: M390 MICROCLEAN.
| Element | CPM S90V | Böhler M390 |
|---|---|---|
| Carbon (C) | 2.3% | 1.9% |
| Chromium (Cr) | 14% | 20% |
| Molybdenum (Mo) | 1% | 1% |
| Vanadium (V) | 9% | 4% |
| Silicon (Si) | Not listed | 0.7% |
| Manganese (Mn) | Not listed | 0.3% |
| Tungsten (W) | Not listed | 0.6% |
Compare Two Knife Steels
Sources and Update Notes
- Dr. Larrin Thomas: knife steel ratings · Property ratings; the scores describe steels rather than individual finished knives.
- Niagara Specialty Metals: CPM S90V
- Böhler: M390 MICROCLEAN
