Steel matchup
MagnaCut and CPM S45VN, compared on the five things that decide a blade: toughness, edge retention, corrosion, heat treat and how each one grinds.
A powder-metallurgy stainless steel balancing high toughness, strong edge retention, and excellent corrosion resistance, widely regarded as one of the most well-rounded modern knife steels.
A premium powder-metallurgy stainless steel from Crucible, built on S35VN with more chromium and nitrogen for stronger edge retention and corrosion resistance at only a small toughness cost.
Dimension by dimension
Each steel's own note, its score out of five, and what separates the two in that one column. The higher score in a row is marked in purple.
| Dimension | MagnaCut | CPM S45VN | What separates them |
|---|---|---|---|
| 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. | Only slightly less tough than S35VN despite the higher carbide load, and still an improvement over S30V once hardness is accounted for. | MagnaCut is tougher. It was purpose-engineered by Larrin Thomas specifically to push toughness further than steels like the S-series, and it shows even against S45VN, itself already a fairly tough member of that family. |
| 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. | Rated around 143% CATRA edge retention versus 440C, matching S30V and beating S35VN, among the better edge-holding stainless steels in this class. | S45VN pulls ahead here, rated around 143% CATRA edge retention versus 440C, a notch above MagnaCut's already-strong wear resistance. The gap is real but modest. |
| 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. | The best corrosion resistance in the S-series thanks to 16% chromium and a nitrogen addition; noticeably better than S35VN in salt-air and marine testing. | Essentially tied at the top of the field. Both use high chromium content and are considered excellent choices for wet, humid, or marine environments. |
| Heat treat | Recommended heat treatment from Crucible: austenitize at 2050 degrees F (1121 C) for approximately 25 minutes, then plate or oil quench, followed by tempering 2x2 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. A dedicated quench plate system makes it much easier to control warping during the plate quench step. For the general principles behind every stage of this process, see our Complete Guide to Heat Treating Knife Steel. | Austenitize at 1950-2000 F (the higher end of this range has shown improved toughness), then quench to below 125 F. Unlike S35VN, S45VN is double tempered at a much higher 600 F for at least 2 hours per cycle, cooling to hand-warm between cycles. This combination typically lands in the 58-61 Rc range, trading a little peak hardness for S45VN's strong all-around balance of edge retention and corrosion resistance. | MagnaCut was specifically designed to be more forgiving to heat treat, reaching excellent properties with equipment accessible to small shops. S45VN uses an unusual high-temperature double temper (around 600 F) that differs from most other premium stainless steels, and benefits from precise, professional-grade equipment. |
| 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. | Grinds similarly to S35VN, moderate for a powder-metallurgy steel; expect faster belt wear than simple carbon or basic stainless steels. | Comparable. Both are moderately demanding powder-metallurgy steels that grind similarly and are noticeably easier to work than steels like CPM S30V or CPM 20CV. |
Best use
MagnaCut
Choose MagnaCut when toughness and chip resistance are the top priority, such as hard-use EDC, hunting, or kitchen knives, and you want a more forgiving shop heat treat.
Open the MagnaCut referenceCPM S45VN
Choose CPM S45VN when maximum edge retention and corrosion resistance are the top priorities and you have access to precise heat-treating equipment.
Open the CPM S45VN reference
The long answer
MagnaCut and CPM S45VN both represent the current high-water mark for balanced, no-major-weakness stainless steel, but they arrived at that balance from different directions. MagnaCut was designed from a clean sheet specifically to maximize toughness without sacrificing edge retention or corrosion resistance, while S45VN is a refinement of Crucible’s long-running S-series aimed at pushing edge retention and corrosion resistance to their limit.
Keep comparing
Keep reading
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Same bench
Whichever steel wins, the grind is only as flat as the platen behind it. I machine the parts, hand-assemble, track and test Torus grinders in Sterling, Illinois.
Current dual-axis platform with a fiber-laser-cut 6061 chassis and single-knob tracking.
Current dual-axis platform with a steel chassis, more mass and less vibration.
Prior-design aluminum chassis, 90-degree tilt and 1.5-inch tooling arms.
One-man shop
Tell me what the blade is for and how you heat treat, and I will tell you which of these I would put on the bench — including when the answer is neither.
