Magnacut
MagnaCut is a modern powder-metallurgy stainless steel designed specifically for knife applications by metallurgist Dr. Larrin Thomas. Released in 2021, it set out to solve a long-standing tradeoff in knife steel design: traditional stainless steels typically sacrifice either toughness or corrosion resistance to reach high hardness and edge retention. MagnaCut keeps nearly all of its chromium in solid solution rather than locking it into large, brittle carbides, which lets it deliver strong toughness, edge retention, and corrosion resistance at the same time, a combination few other steels can match.
Also known as: CPM MagnaCut, Magnacut
Composition
| Carbon (C) | 1.15% |
| Chromium (Cr) | 10.7% |
| Vanadium (V) | 4.00% |
| Molybdenum (Mo) | 2.00% |
| Niobium (Nb) | 2.00% |
| Nitrogen (N) | 0.20% |
Properties
| Property | Rating | Notes |
|---|---|---|
| Toughness | ★★★★★ | In Charpy impact testing at 62.5 HRC, MagnaCut delivers roughly 38 ft-lbs of toughness, about 40% tougher than S35VN at similar hardness, and roughly double the toughness of M390. It performs on par with tough non-stainless steels like CPM 4V and Vanadis 4 Extra. |
| Edge Retention | ★★★★☆ | CATRA edge-retention testing places MagnaCut between S35VN and S45VN, very good, though not at the extreme end occupied by steels like S90V or M390. |
| Corrosion Resistance | ★★★★★ | MagnaCut keeps its full 10.7% chromium in solid solution, giving it corrosion resistance that exceeds S35VN, S45VN, M390, and 20CV, among the best of any high-performance knife steel, approaching though not quite reaching saltwater-grade steels like Vanax or LC200N. |
| Machinability / Grinding | ★★★☆☆ | Like other vanadium-rich powder-metallurgy steels, MagnaCut is moderately demanding to grind because of hard vanadium and niobium carbides. Expect belt wear similar to or slightly higher than S35VN; ceramic or high-quality zirconia belts are recommended for stock removal. |
Heat Treatment
Recommended heat treatment from Crucible: austenitize at 2050 degrees F (1121 C) for approximately 25 minutes, then plate or oil quench, followed by tempering 2×2 hours at 350 degrees F (176 C). This typically yields 61-62.5 HRC. An optional cryogenic treatment (dry ice or liquid nitrogen) immediately after quenching can push hardness to 63-65+ HRC.
Because MagnaCut is a stainless PM steel, it should be heat treated in a foil-wrapped or controlled-atmosphere environment to prevent scale and decarburization, and requires an oven capable of holding precise soak temperatures.
Best Uses
This rare combination of toughness, edge retention, and corrosion resistance makes MagnaCut an excellent general-purpose and hard-use knife steel, well suited to EDC knives, hunting and fillet knives, and outdoor or survival blades that may see rough use in wet conditions.
Sources: Crucible Industries, CPM MagnaCut Data Sheet. Larrin Thomas, CPM MagnaCut: The Next Breakthrough in Knife Steel, Knife Steel Nerds, March 2021.