D2’s an interesting alloy: It’s not just a common knife steel, but a popular tool steel that’s been used in commercial machining for decades. D2’s one of the only tool steels that technically qualifies as stainless. This alloy’s now widely used in budget blades. Let’s see why it’s one of the best blade steels you can choose for an affordable EDC knife.
- D2 Steel Composition
- D2 As a Knife Steel: Reviewed
- Edge Retention
- Toughness
- Hardness Rating
- Sharpness Potential Tested
- D2 Steel vs 8Cr13MoV
- D2 Steel vs 440c
- D2 Steel vs S30V
- D2 Steel vs 154CM
- D2 Knife Recommendations
D2 Steel Composition
- Carbon: 1.4% – 1.6%
- Chromium: 11% – 13%
- Cobalt: 1.0%
- Copper: 0.25%
- Manganese: 0.6%
- Molybdenum: 0.7% – 1.2%
- Nickel: 0.3%
- Phosphorus: 0.03%
- Silicon: 0.6%
- Sulfur: 0.03%
- Vanadium: 1.1%
D2 As a Knife Steel: Reviewed
D2 steel’s composition is interesting. Its high chromium content produces loads of carbides within the steel’s structure providing high hardening capability. Because of all that chromium, D2 also has the greatest corrosion resistance of all tool steels. Paired with its high carbon content, D2 resists deformation and provides long wear performance. Used in a knife blade, that means good edge retention.
Edge Retention
When subjected to an edge-holding test against 45 other knife steels, D2 placed 24th. While that might not sound impressive, it’s important to also note that this steel was heat-treated to obtain a lower hardness rating (59.2 HRC) than nearly all other tested steels — including nearly all steels that had worse edge retention.
That’s a good thing: A softer blade that still holds an edge well means it’ll also be stronger, more flexible, and more capable of chopping and making heavy cuts without quickly dulling or damaging.
More importantly, we can logically conclude that with a higher hardness rating, D2 will hold an edge even better. But how hard can it get?
Toughness
D2’s primary downside is its lack of toughness. Because it has a high carbon, cobalt, nickel, and vanadium content, D2 steel has excellent hardness and edge retention — but it is a more brittle steel than other stainless alloys because of these plentiful carbides. D2 still affords enough toughness to be used in an EDC knife or fixed blade, but it’s more likely to suffer edge chips or blade damage if you use it to strike or chop.
Hardness Rating
Because of its high carbide content and diverse composition, D2 enjoys a wide range of potential rockwell hardness ratings. With a mild temper (400ºF), this alloy can be hardened up to 61 HRC. With an aggressive temper (1,000ºF), it can be made soft, measuring 54 HRC.
In our guide to Steel Hardness Ratings for Knives, we explained how blades measuring 61 HRC and up have great edge retention and are well suited for fine cutting applications, like high-end kitchen cutlery. Softer steels measuring 54 to 56 HRC are great for large fixed blades, choppers, and tactical knives meant to take abuse.
Any hardness rating in between — 57 to 60 HRC — provides a good balance between sharpness potential and edge toughness. This is one reason why D2 makes such a great knife steel: It’s highly versatile and can be tailored for different applications (like a filet knife or camp ax) through heat treatment alone.
Sharpness Potential Tested
Some argue that because of its large carbide inclusions, D2 steel blades can struggle to obtain sharp edges. I disagree. When I reviewed the CIVIVI Elementum — which has a D2 blade — I found it had a modest out-of-the-box sharpness rating of 201g. That placed it in the bottom half of tested knives.
But that rating was based on a basic factory edge. So, to prove D2 steel can be honed to high sharpness, I spent a few minutes with my Elementum on my Wicked Edge Sharpener. I didn’t re-profile the blade and merely kept my stones’ angles at the factory 20-degree apex the knife came with.
After about 5 minutes of grinding with 3,000-grit diamond stones and some quick passes on a leather strop, I measured how sharp I was able to get this steel.
It measured 79 grams and 82 grams on my certified edge tester, for an average 80.5g. Let’s call it 81g. That’s well within straight razor territory, approaching surgical sharpness (< 50g). At publication, this D2-bladed Elementum is now the sharpest knife in my collection by a healthy margin.
So, the myth that D2 can’t be finely honed is busted. This alloy has very high sharpness potential and it takes little effort to get there. When first reviewing the Elementum, I found it retained 72% of its factory edge. Excellent performance, thanks to all that carbon, chromium, and D2’s other plentiful carbides.
D2 Steel vs 8Cr13MoV
D2 is a harder, sharper, and longer-wearing steel than 8Cr13MoV. The former contains twice as much carbon: 1.4% to 1.6% compared to 8Cr13MoV’s 0.7% to 0.8%. The latter steel’s chromium content — 13% to 14.5% — makes it a proper stainless steel, so it’ll resist rust and corrosion better than D2.
But its lower carbon content means 8Cr13MoV is a softer steel. It has a lower hardness rating, between 58 and 59 HRC, while D2 can be hardened up to 61 HRC. If both steels are hardened at 58 to 59 HRC, D2 will likely provide better wear and edge retention, primarily because of its higher carbon content.
But 8Cr13MoV provides some advantages over D2: Being a flexible steel with lower carbon content, it’ll provide higher strength and edge toughness at comparable hardness ratings. A blade made from 8Cr13MoV is almost always going to cost less, too — it’s just cheaper to make than D2.
A properly heat-treated and ground blade made from 8Cr13MoV can still be a high performer, too. When I reviewed the CRKT CEO, its 8Cr13MoV blade had excellent sharpness out of the box (183g) and it retained 90% of its edge during testing. That made it one of my best-ranked knives at publication.
D2 Steel vs 440c
For small knife applications, D2 steel is comparable to 440c. The former provides slightly better edge retention and sharpness potential while the latter, a stainless steel, provides better corrosion resistance and toughness. The 440c alloy contains about 25% to 30% less carbon (0.95% to 1.2%) and up to 40% more chromium (16% to 18%).
440c can obtain a relatively high hardness rating of 60 HRC. Coupled with its high carbon and chromium content, 440c is a solid competitor to D2 for sharpness and edge holding. During testing, D2 only performed 15% better when it came to edge retention. The 440c blade used during that test was only hardened to 57 HRC. If it was hardened to its maximum potential of 60 HRC, it’s highly likely 440c could’ve outperformed the D2 blade in edge retention.
D2 Steel vs S30V
S30V is superior to D2 steel. Although it contains similar amounts of carbon (1.45%) and chromium (14%), S30V also contains many more carbides formed by Molybdenum (2%), Vanadium (4%), and Niobium (0.5%). S30V is a CPM (crucible powdered metallurgy) steel. That means its formed from powdered metal instead of a conventional billet, like D2.
The carbide inclusions in CPM steel are smaller and more uniformly distributed within the alloy’s grain structure, which significantly improves performance: The finished blade is easier to machine and grind, and it has higher sharpness potential. Its uniform grain structure improves flexibility without sacrificing edge performance. It can also be sharpened more easily and consistently.
In testing, S30V held an edge 13% longer than D2 with a nearly identical hardness rating (59.8 HRC against D2’s 59.2 HRC). To be clear, S30V is a premium stainless alloy with high amounts of exotic carbides, developed in partnership between Crucible Industries and the legendary knifemaker Chris Reeve. D2 is a budget tool steel, and its only advantage over S30V is its comparatively low cost.
D2 Steel vs 154CM
D2 is comparable to 154CM steel. 154CM is a high-carbon stainless developed by Crucible Industries for industrial applications, like D2. 154CM is a modification of the 440c alloy, with reduced chromium content and more molybdenum. It contains 1.05% carbon and 13.5% to 14% chromium, with 4% molybdenum and 0.5% manganese filling out the bulk of its other carbides.
154CM can be hardened to 61 HRC, making it an excellent alloy for high-end cutlery and small, sharp EDC knives. Its lower carbon content relative to D2 means 154CM has less overall edge-holding ability, but it benefits from a lower risk of chipping and cracking. It will also provide better corrosion resistance.
D2 Knife Recommendations
D2 steel is like the American V8: It’s been around for decades, refined to near perfection, and now it’s found in hundreds of cheap, good knives. It’s tough to go wrong when picking any D2 blade, but these are my personal favorites based on overall build quality.
CIVIVI Elementum
The Elementum’s blade and profile complement D2 steel’s intended purpose perfectly: It’s a small but sturdy little EDC knife that balances toughness and sharpness in a no-frills, reliable package. In my review, I found the Elementum to be a surprisingly well-built knife for its ~$50 price, with a smooth action that’s fun to flip, and a quality blade with solid grinds and a decent factory edge. The grip’s comfortable, and it fits in the pocket nicely with no bulk or fuss.
Kershaw Emerson CQC-6K
Kershaw’s $50 CQC-6K is an awesome clip point EDC option with a very comfortable G10 handle and reliable high flat grind. Its D2 blade sports a stonewashed finish that looks great and will wear even better over time, while plenty of knurling and jimping along the spine and scales give plenty of grip when things get sweaty or slick. It’s a lightweight knife at 5.1 ounces, and its reversible belt clip ensures you can carry and draw this blade to your liking and handedness.
CRKT Squid XM
Another affordable, no-bones $50 flipper, the Squid XM from CRKT provides ample lock-up with a big ole’ frame lock. It, too, sports comfortable and grippy G10 scales while its stout drop point D2 blade with a high grind balances toughness and sharpness for reliable daily cutting and slicing. CRKT includes a high-quality IKBS bearing and large thumb stud for easy one-handed deployment.