Knife Steel Guide: 8Cr13MoV, 420, D2, MagnaCut, S90V and Damascus
Knife steel is a three-way trade between edge retention, toughness and corrosion resistance, and price tracks how well a steel balances them. Budget stainless such as 8Cr13MoV and 420 is easy to sharpen and rust-resistant but dulls fast. D2 holds an edge far longer but can spot if left wet. CPM MagnaCut and S90V are premium powder steels that hold an edge for a long time while staying stainless. Damascus is a construction, not a single steel.
The three properties that matter
Edge retention is how long the knife stays sharp. Toughness is how well the edge resists chipping when it hits bone or a staple. Corrosion resistance is whether it rusts. No steel maxes all three, and heat treatment can move a given steel up or down, so a well-treated budget steel can outperform a badly treated premium one. A fourth factor, ease of sharpening, is the flip side of edge retention: steels that dull slowly also take longer on the stone.
Listings on Atlas Knife Co usually name the steel in the title, which is the first thing to read. If a listing says only stainless, assume a basic alloy.
Budget stainless: 8Cr13MoV, 420 and 440C
8Cr13MoV is the standard steel on inexpensive folders and fixed blades. It sharpens quickly, resists rust well and is tough enough for daily use; it simply needs sharpening more often. The ABKT Tac Grunt linerlock and fixed blades and the ABKT TAC Recon Ops neck knife use it. 420 stainless is softer still and shows up on fishing and kitchen knives where rust resistance is the priority; Smith's Sharpeners lists its Bait Breaker, Lawaia and Mr. Crappie fillet knives and its Cabin and Lodge steak set in 420. 440C is a step up in hardness and edge retention while staying stainless, and appears on the Aurora Survival Fire Starter's striking blade. These steels are the right choice for a knife that will be abused, lost or lent.
D2 tool steel
D2 is the value champion of the mid range. Originally a die steel, it is hard and wear-resistant, so it keeps a working edge through far more cutting than 8Cr13MoV. It contains enough chromium to be called semi-stainless but not enough to be rust-proof; it will develop spots if stored wet. It is also somewhat harder to sharpen and can chip if the edge is ground very thin. ABKT TAC builds most of its mid-priced line on it: the Catalyst, Predator, Warthog, Night Stroke, Elite and Kambo linerlocks, the Siege and Interlace slide locks, and the Shadow Predator and Desert Predator fixed blades. For a daily-carry folder in the thirty to sixty dollar range, D2 is the steel to look for.
Premium powder steels: CPM MagnaCut and S90V
Powder metallurgy steels are made from atomized steel powder pressed into a billet, which gives a finer, more even grain than conventional casting. CPM MagnaCut was designed to combine high toughness and edge retention with genuine stainless performance, which is why it has become popular for small fixed blades used outdoors. The AuCon Fanglet fixed blades and the AuCon IMP magnetic folders are listed in it. S90V sits at the far end of edge retention: it stays sharp for a very long time, is stainless, but is brittle compared with MagnaCut and slow to sharpen. The Artisan Caruso titanium Damascus folder carries an S90V blade. Expect to pay well over a hundred dollars for either steel in a finished knife, and keep a diamond stone for sharpening.
Damascus, san mai and titanium
Damascus is layered steel, and its performance depends on which steels were layered. The Alabama Damascus Steel blanks and the Tenable, Artisan, Bear & Son and Old Bear Damascus knives should be treated as high-carbon: keep them dry and oiled. San mai, as on the ACEJET SanMai hunters, wraps a hard core in softer cladding, so the edge steel and the jacket are different things. Titanium, on the AuCon Knife Tool and Anso tools and the Artisan framelocks, is a handle and frame material rather than a blade steel; it is light and does not corrode, but it is too soft to hold a good edge. Timascus, on some AuCon tools, is layered titanium used purely for its color.
FAQ
Which knife steel is best for everyday carry?
For most people D2 gives the best balance of edge retention and price. If budget allows, CPM MagnaCut adds rust resistance and toughness without giving up edge life.
Is 8Cr13MoV a bad steel?
No, it is an honest budget steel. It dulls sooner than D2 but sharpens in minutes and resists rust well, which suits a knife that gets used hard and put away wet.
Why is S90V so expensive to sharpen?
Its high vanadium carbide content is harder than most sharpening stones. A diamond stone cuts it; ceramic and natural stones struggle.
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