Knife steel

MagnaCut knife steel

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.

Also known as

CPM MagnaCut

At a glance

How MagnaCut behaves

The four meters are relative to the rest of the database. Composition is the published nominal analysis, not a mill certificate for your bar.

Working properties

Toughness: 5 / 5
Edge retention: 4 / 5
Corrosion resistance: 5 / 5
Ease of grinding: 3 / 5

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%
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. Browse more entries in the Knife Steel Database to compare it against other options.
Sources: Crucible Industries, CPM MagnaCut Data Sheet. Larrin Thomas, CPM MagnaCut: The Next Breakthrough in Knife Steel, Knife Steel Nerds, March 2021.

At the bench

What each property means for this steel

Open the property you are worried about. Every note is written for the blade in your hand, not for a spec sheet.

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.

Grinding and machinability

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 treat

Recommended heat treatment from Crucible's CPM MagnaCut data sheet: preheat at 1550-1600 degrees F, austenitize at 2050 degrees F (1120 C) for 20 minutes (Crucible's hold-time chart runs from 30 minutes at 1950 F to 5 minutes at 2200 F), quench to below 125 F with a plate, air or positive-pressure gas quench (or a salt or interrupted oil quench to about 1000 F, then air), then double temper at 350 degrees F (175 C) for at least 2 hours each, cooling to hand warm between. Crucible's aim is 60-63 HRC. For that recipe its table lists 61.5 HRC after a plate or oil quench and 62 HRC with dry ice or liquid nitrogen after the quench, and Larrin Thomas reports around 61-62.5 HRC. Higher hardness needs a different cycle: with a 300 F temper the same 2050 F austenitize gives 62.5 HRC (63 HRC with dry ice or liquid nitrogen), and the table's results of 64-65 HRC all come from austenitizing at 2100-2200 F with a cold treatment (a freezer for 64-64.5 HRC, liquid nitrogen or dry ice for 64-65 HRC, or cryo in a vacuum furnace for 64 HRC), mostly with a 300 F temper; one cell, 64 HRC, is a 350 F temper at 2200 F with liquid nitrogen or dry ice. At the recommended 2050 F and 350 F cycle a cold treatment is optional, and Crucible warns that tempering above 750 F reduces corrosion resistance. 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.

The full reference

More on 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.

MagnaCut FAQ

What hardness does MagnaCut reach?

With Crucible’s recommended heat treatment (2050°F austenitize, 350°F double temper), MagnaCut reaches 61.5 HRC after a plate or oil quench and 62 HRC after dry ice or liquid nitrogen, and Larrin Thomas reports around 61-62.5 HRC. Harder results, up to 64-65 HRC, need a hotter 2100-2200°F austenitize and a cold treatment, usually with a lower 300°F temper; Crucible’s hardness table also lists 64 HRC at 2200°F with a 350°F temper and liquid nitrogen or dry ice. See the heat treat details further up this page for the full recipe.

Is MagnaCut worth the extra cost over CPM 20CV or CPM S45VN?

For most users, yes, if toughness and chip resistance are a priority. MagnaCut is noticeably tougher than both while matching or beating their corrosion resistance, though CPM 20CV and S45VN each hold a slight edge-retention advantage. See the full breakdowns: MagnaCut vs CPM 20CV and MagnaCut vs CPM S45VN.

Does MagnaCut rust?

Not meaningfully more than other high-chromium stainless steels. MagnaCut’s corrosion resistance is on par with the best modern stainless knife steels, so normal care (wiping down and drying after wet use) is enough to keep it rust-free.

Gloved hands dry a wet chef's knife with a gray cloth on a black nonslip mat, water droplets scattered around it.

Is MagnaCut hard to sharpen?

It is more demanding than simple carbon steels, but it is considered one of the more sharpenable premium stainless steels for its performance class, since most of its chromium stays out of large carbides. Diamond or CBN abrasives are recommended for maintaining an edge once hardened. See the full grinding and sharpening guide for belt and abrasive recommendations.

Hands draw a small fixed knife across a fine diamond sharpening plate seated in a black nonslip holder.

Is MagnaCut a good first knife steel to work with?

Not usually. It is a capable steel, but not the easiest to heat treat at home. It needs a foil-wrapped or controlled-atmosphere oven and precise soak temperatures to reach its full potential. New makers are often better off starting with a simpler steel like 1084 before working up to MagnaCut.

Folded foil packet shaped like a knife blade lies on a steel tray beside the open, cold chamber of a heat-treat kiln.

What is MagnaCut best used for?

General-purpose EDC, hunting, and kitchen knives where excellent all-around performance and a low risk of chipping both matter. See the Best Uses section further up this page for more detail.

Small utility knife, drop-point hunting knife and slim kitchen knife lie on separate slate pads with a sheath and board behind.

Head to head

Compare steel data for MagnaCut

Every matchup MagnaCut appears in, dimension by dimension.

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Keep reading

Guides that use this steel

Grind MagnaCut on a machine that holds still

Whatever the steel, the grind is only as flat as the platen behind it. I machine the parts, hand-assemble and test Torus grinders in Sterling, Illinois.

See the whole shop

Nova 2×72 Aluminum Belt Grinder
Current dual-axis platform with a fiber-laser-cut 6061 chassis and single-knob tracking.
Starts at$1,295View
Nebula 2×72 Steel Belt Grinder
Current dual-axis platform with a steel chassis, more mass and less vibration.
Starts at$1,295View
Torus 2×72 Classic Aluminum Belt Grinder
Prior-design aluminum chassis, 90-degree tilt and 1.5-inch tooling arms.
- Machined 6061 aluminum chassis with stainless, plated Grade 8 and alloy shoulder-bolt hardware
- 304 stainless ratchet belt tensioner and a 90-degree tilt: loosen the handle, pull the pin
- Standard 1.5-inch tooling arms, deep slack platen and 4-inch drive wheel included
Starts at$995View

One-man shop

Thinking about MagnaCut?

Tell me what the blade is for and how you heat treat. I will tell you whether this is the steel I would use, and what I would use instead.

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