D2 Steel: What It's Good At, and Which of Our Multitools Use It

D2 is a tool steel — a grade built for one job, resisting wear. Its composition settled into a standard in the 1930s: roughly 1.5% carbon, around 12% chromium, plus molybdenum and vanadium. It has been used in knives since the mid-1960s and remains one of the most common blade steels in folding tools.

This page covers what D2 does well, where it stops being the right choice, and — in the second half — the nine multitools we build with it.

What D2 is

Tool steels are designed for industrial cutting and forming, where what wears a tool out is abrasion rather than rust. D2 comes from that family.

The carbon in it forms carbides: hard particles suspended in the surrounding metal, and the carbides are what an edge actually cuts with. D2 carries a large volume of them. That is the source of everything it does well, and of most of its limits.

What D2 does better than ordinary stainless

An edge in D2 stays useful after a general-purpose stainless has gone blunt. Edge-retention testing published by Knife Steel Nerds, using CATRA data from Bohler Uddeholm, places D2 above the common stainless grades — 440C, N690, ATS-34 and 154CM — and roughly level with 3V.

If you cut something most days, that is the difference between sharpening now and then and sharpening constantly. It is also why D2 is common on working tools rather than display knives.

It costs less than the steels that beat it

D2 is made by conventional steelmaking: melted, cast, rolled and annealed. The steels that out-wear it are made by powder metallurgy, in which the melt is atomised into fine droplets and consolidated back into a solid. That produces a finer, more even structure — and a more expensive way to make steel, which the material price reflects.

D2 is also a mature grade, produced by many mills under many names including SKD11, 1.2379, SLD and Sverker 21. Between the two, it occupies the middle: better edge life than ordinary stainless, at a lower cost than the powder steels above it.

The hardness is not part of the grade

D2 describes what is in the steel. It does not tell you how hard the finished blade is, because hardness is set by heat treatment — how hot the blade was taken, how fast it was cooled, and how it was tempered afterwards.

That matters, because hardness is a trade. A harder blade resists wear for longer, but chips more readily and takes more time on the sharpening stone. A maker chooses a point on that line to suit the tool, so two blades of the same D2 can end up several points apart on the Rockwell C scale while both are described accurately.

The practical consequence: when you read a specification, the hardness number tells you more than the steel name does. If a listing names the steel and not the hardness, it has told you half of what matters.

Why folding tools use it

D2 hardens in air, and that has less to do with cutting than with building.

Most simple high-carbon steels have to be quenched in oil, which cools the part unevenly and can warp it. A folding multitool blade has to sit in a frame with a fraction of a millimetre of clearance. A blade that emerges from heat treatment slightly warped is not a slightly worse blade; it is a blade that does not fit, and the whole tool is scrapped. Air hardening keeps the blade straight through the process.

It is the least visible reason D2 turns up in folding tools as often as it does, and one of the strongest.

Where D2 stops being the right choice

It is not stainless. D2 is often described as having 12% chromium, which sounds like a stainless steel. But chromium only resists rust while it is dissolved in the metal; chromium pulled into a carbide stops protecting the surface. D2 carries so much carbon that a large share of its chromium ends up in carbides rather than in solution, which leaves it with roughly half the dissolved chromium of a true stainless steel — despite the figure on the datasheet. If your tool lives wet — coastal work, a boat, a pack that stays damp for days — a higher-chromium steel will serve you better.

A very fine edge is not its strength. D2's carbides are large and unevenly distributed. That limits how thin the edge can safely be taken, and it makes a polished edge hard to reach. D2 takes a working edge rather than a show edge.

It is not the longest-wearing steel available. Powder steels wear longer again, and the corrosion-resistant ones manage that without rusting.

Everything above applies to D2 wherever you meet it. The rest of this page is about where you meet it in our own line.

Which of our multitools use D2

Nine of our multitools carry a D2 main blade. Here they are, grouped by type, with what each one carries:

Model	Type	Functions	Features
MT-04	Pliers-based multitool	19-in-1	3-in-1 pliers head · pry bar, hex key, hook knife, heavy-duty awl · nylon sheath
MT-11	Pliers-based multitool	20-in-1	Heavy-duty 440A spring-retractable scissors with rounded safety tips · 3-in-1 pliers head · detachable magnesium fire starter rod
MT-12	Pliers-based multitool	20-in-1	Same as the MT-11, in coyote brown
MT-13	Pliers-based multitool	20-in-1	Same as the MT-11, in green
MT-61	Pliers-based multitool	20-in-1	3-in-1 precision pliers · corkscrew and seal cutter · glow-in-the-dark strip
MT-74	Pliers-based multitool	20-in-1	Same platform as the MT-11, matte black with blackened hardware
MT-07	Knife, no pliers	5 tools	Modular 2-in-1 design splits into two independent halves · tungsten glass breaker · Phillips and flathead screwdrivers
MT-18	Knife, no pliers	10-in-1	Luminous handle strips · tungsten glass breaker · 130g ultra-lightweight
MT-73	Shears, no pliers	11 tools	Large spring-action shears · seatbelt cutter · ferro rod and whistle · glass breaker

Every model page lists the complete specification for that tool.

Every one of these models uses the same steel at the same 60–62 HRC band, which is why the table compares type and function count instead of hardness — there is no hardness ladder to climb here. What separates them is what kind of tool they are: six are pliers-based, two are built around a blade, and the MT-73 leaves the pliers out in favour of large spring-action shears. Within that, the MT-11, MT-12, MT-13 and MT-74 are one platform in four finishes, so choosing among those four is about colour and hardware finish rather than capability.

One detail is worth checking for generally: the MT-73's blade carries an anti-rust stonewashed coating. Coatings are one way of managing D2's weakness, so if you work in wet conditions it is worth seeing whether the model you are considering has one.

How to choose between them

Work from your own priority:

• Hard cutting and prying — the MT-04 is the one built for it, with a pry bar, hex key, hook knife and heavy-duty awl in its 19-in-1 set.
• Fire starting built into the tool — the MT-11, MT-12, MT-13 and MT-74 carry a detachable magnesium fire starter rod that mounts onto the pliers; the MT-73 includes a ferro rod and whistle.
• A working pair of scissors — the MT-11, MT-12, MT-13 and MT-74 all share the same 440A spring-retractable scissors with rounded safety tips.
• Carrying it every day — the MT-18 at 130g is the lightest tool here whose weight we state.
• Camp and roadside tasks — the MT-61 carries a corkscrew and a seal cutter.
• Rescue and emergency work — the MT-73 leaves out the pliers entirely and builds around large spring-action shears and a seatbelt cutter.
• Splitting the tool in two — only the MT-07 does that.
• Choosing a finish rather than a tool — the MT-11, MT-12, MT-13 and MT-74 are the same multitool; the choice is between matte black, coyote brown, green, or black with blackened hardware.
• Working near water — D2 is the wrong choice, and one of our higher-chromium models will suit you better.

If two models look close, open their product pages. Weight and the full tool list are what most change how a tool feels in use, and the type alone will not tell you either.

For a closer look at the MT-73's shears — and the case for a rescue tool built around its shears rather than its blade — see what emergency shears are for.