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M390 has higher abrasive edge-retention and corrosion-resistance ratings than S45VN, while S45VN has a small toughness lead. Both are stainless powder steels, so the choice is about how much those differences matter in the knives available to you.
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 S45VN | Böhler M390 |
|---|---|---|
| Abrasive edge retention | ||
| Toughness | ||
| Corrosion resistance |
Heat treatment, hardness and geometry affect actual knives.
M390 Leads Abrasive Edge Retention
M390 rates 6.5 for abrasive edge retention and S45VN 5.5. We would lean toward M390 for frequent abrasive slicing if the knives are equally well suited to the job.
The one-point gap does not establish a fixed improvement in cutting time. Blade geometry and treatment can make the practical comparison less tidy than the chart.
Our S45VN steel profile explains its properties and care in more detail.
The Toughness Gap Is Small
S45VN rates 4 for toughness and M390 3.5. We would describe that half-point difference as small, rather than claim S45VN makes a knife substantially more damage resistant.
If toughness is your central concern, compare the finished edge and the maker’s intended use. This close score difference should not carry the purchase by itself.
Our M390 steel profile explains its properties and care in more detail.
M390 Has the Higher Corrosion Rating
M390 rates 9 for corrosion resistance and S45VN 8. Both are stainless steels, with M390 providing more rated corrosion margin.
For routine carry, normal cleaning and drying still apply. The corrosion score does not establish the resistance of every other part of the knife.
Let the Actual Knife Break a Close Decision
For wear-heavy cutting, M390 has the clearer material advantage. For otherwise appealing S45VN knives, its small toughness lead and lower corrosion score should be weighed alongside the actual design.
We would prioritize the handle, grind and actual price if your cutting demands are modest. Neither steel makes an unsuitable knife the right one.
Composition
Our steel composition guide explains the elements and the differences between reported values, ranges and limits.
CPM S45VN: Selected nominal/typical values, mass %; not a batch certificate or complete analysis. Niagara Specialty Metals: CPM S45VN.
Böhler M390: Böhler average composition, mass %; selected elements, not a batch analysis. Böhler: M390 MICROCLEAN.
| Element | CPM S45VN | Böhler M390 |
|---|---|---|
| Carbon (C) | 1.48% | 1.9% |
| Chromium (Cr) | 16% | 20% |
| Vanadium (V) | 3% | 4% |
| Molybdenum (Mo) | 2% | 1% |
| Niobium (Nb) | 0.5% | Not listed |
| Nitrogen (N) | 0.15% | Not listed |
| 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 S45VN
- Böhler: M390 MICROCLEAN
