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CPM 20CV favors abrasive edge retention; MagnaCut trades some of that wear resistance for higher toughness and a small corrosion-resistance lead. If you are choosing between two versions of a knife, the useful question is what you want from the edge: longer wear during repeated slicing, or more resistance to chipping. Neither steel wins every part of the comparison.
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.
The toughness score of 7 is for original Crucible MagnaCut. In written feedback to KnifeInformer, Dr. Thomas provided a toughness rating of 8.5 for Erasteel MagnaCut; his January 2026 testing explains the differences between the two versions. This table uses the original version.
| Property | CPM 20CV | CPM MagnaCut |
|---|---|---|
| Abrasive edge retention | ||
| Toughness | ||
| Corrosion resistance |
Heat treatment, hardness and geometry affect actual knives.
When 20CV’s Wear Resistance Is Worth Choosing
20CV scores 6.5 for abrasive edge retention, compared with MagnaCut at 5. For lots of cardboard or other abrasive slicing, that gives 20CV a reason to stay on your shortlist. The numbers are ratings, not a forecast of how many boxes you can cut or a promise of 30% longer edge life.
This comparison will look familiar if you have read about M390 or CTS 204P. Dr. Larrin Thomas groups those steels with 20CV in the same ratings row. There is no separate numerical advantage for 20CV hidden behind the different name; the particular knife and its heat treatment still deserve attention.
Our 20CV steel profile covers its alloy background and care.
What MagnaCut Gives You in Return
Original MagnaCut rates 7 for toughness, compared with 20CV at 3.5. That is the more persuasive reason to choose MagnaCut if chipped edges have been a problem. It does not mean a finished MagnaCut knife is twice as tough, and it does not turn a thin blade into a pry bar.
Before replacing a knife that chips, look at the edge angle and how it is used. Heat treatment and geometry affect the outcome alongside the steel. A higher toughness rating gives the maker more room to work with; it cannot tell you whether a specific factory edge suits your cutting.
The MagnaCut steel profile explains its design and the differences between production versions.
Corrosion Resistance and Sharpening
Both steels rate highly for corrosion resistance: 20CV at 9 and MagnaCut at 9.5. We would treat that half-point gap as a small published difference, not a reason to call 20CV unsuitable for everyday carry. For wet use, we would lean toward MagnaCut when the rest of the knife also suits the conditions. Rinse away salt or food residue and dry either knife before storage.
More chromium does not automatically mean better rust resistance. 20CV contains 20% chromium and MagnaCut 10.7%, but how much remains available in the steel rather than bound in carbides matters. MagnaCut was designed to avoid chromium carbides in its heat-treated structure.
Diamond or cubic boron nitride (CBN) abrasives are practical options for sharpening either steel, particularly when repairing damage or changing an edge angle. The ratings do not measure sharpening speed. Edge thickness, the abrasive and the amount of metal you need to remove matter, so we would not attach a fixed time saving to either choice.
Is MagnaCut Worth Paying More For?
If the same knife is offered in both steels, start with the price difference and the maker’s specifications. Paying more for MagnaCut makes sense when its toughness addresses a real need. If your cutting mostly wears the edge dull and your 20CV knife holds up well, changing steels may bring little benefit and gives up some abrasive-wear resistance in this framework.
For different knife models, handle comfort, blade thickness and overall design can outweigh the steel choice. We would choose a well-suited 20CV knife over an awkward MagnaCut knife. Our knife steel guide explains how these properties fit into the wider buying decision.
Composition
Our steel composition guide explains what the elements do and how to read these values.
CPM 20CV: Niagara typical composition, mass %; selected elements, not a batch analysis. Niagara Specialty Metals: CPM 20CV.
CPM MagnaCut: Niagara typical composition, mass %; selected elements, not a batch analysis. Niagara Specialty Metals: CPM MagnaCut.
| Element | CPM 20CV | CPM MagnaCut |
|---|---|---|
| Carbon (C) | 1.9% | 1.15% |
| Chromium (Cr) | 20% | 10.7% |
| Molybdenum (Mo) | 1% | 2% |
| Vanadium (V) | 4% | 4% |
| Tungsten (W) | 0.6% | Not listed |
| Niobium (Nb) | Not listed | 2% |
| Nitrogen (N) | Not listed | 0.2% |
Compare Two Knife Steels
Sources and Update Notes
- Dr. Larrin Thomas: knife steel ratings · Property ratings and the effects of edge geometry.
- Niagara Specialty Metals: CPM 20CV datasheet · Typical composition and powder metallurgy process.
- Niagara Specialty Metals: CPM MagnaCut datasheet · Typical composition and material properties.
- Dr. Larrin Thomas: Erasteel and original MagnaCut · Research comparing the two versions; the numeric 8.5 rating was supplied separately in written feedback.
