Contents
Steel knives D2 (K110) are very popular as materials for blades in custom cutlery.
D2 steel knives are inexpensive but still have good wear resistance and have excellent wire tightness.
Most D2 steel knives are easy to manufacture.
Get ready to consume the tapes because once hardened to make the finish it will be a nice adventure!
The story
The use and diffusion of D2 steel began during the Second World War but today in the maker sector it is a steel that continues to be widely used to make very resistant and high quality knives.
D2 steel was used to make molds for production lines.
The original and even more common use of D2 steel was not only to cut the other steel by pressing down with the mold shearing blades, but doing it repeatedly again and again in a factory thousands of times and proving to have unique features.
Throughout the history of the modern knife, many high-end knife steels (especially 154 CM) have been indirectly adapted into other fields such as knife making due to the innovation and direct experience of steel in the field of molds and tools.
This steel has a very long working history that allows you to determine the strengths of D2 knife steel.
Key feature of D2 steel is hard,it has an air-hardening, high carbon and very high chromium composition which makes this high-end knife steel with a hardness detected at the durometer in the range of 55 to 62 HRC.
Chromium-rich alloy carbides create excellent wear resistance from slip contact with other metal or abrasive materials, thus creating a durable knife that also holds the wire well.
The very high chromium content offers better corrosion resistance than most tool steels and allows it to be semi-stainless.
D2 steel is an alloy tool steel with a high chromium content and high carbon content.
Its high wear resistance is ideal for tools that need less frequent sharpening and is ideal for cutting and deformation tools.
D2 steel has the highest carbon composition among tool steels.
Its glossy finish makes it look like stainless steel despite a chromium content of only 11.5% and for this reason D2 steel is sometimes known as “semi-stainless steel”.
D2 steel belongs to the group of cold-working tool steels which means that D2 steel undergoes shaping after cooling.
D2 steel is also produced using air hardening or oil hardening, and the result will allow D2 steel to maintain its hardness.
Composition of steel D2
Many steel mills produce their own D2 steel, but the composition remains very close to the norms: the composition of the D2 blade steel alloy provides guidance to its unique qualities:
- Carbon (C) 1.50 to 1.68 percent: Contributes to hardness, wire tightness, tensile strength and wear resistance. Compared to other “high carbon” steels, this one contains a lot of carbon. It is this amount of carbon that accounts for much of the hardness of D2 steel and edge retention.
- Chromium (Cr) 11.50 to 12.00 percent: It contributes to strength and wear resistance, also, corrosion resistance. Stainless steel contains 13% chromium. This value does not reach the chromium content required for what is considered “stainless steel”. But it offers better corrosion resistance among non-stainless steel types. That is why D2 steel is considered a “semi-stainless” steel.
- Molybdenum (Mo) .60 to .90 percent: Contributes to workability, corrosion resistance and resistance to high temperatures. It increases hardenability, resistance to high temperatures and creep resistance, and also helps with corrosion resistance.
- Vanadium (V) .90 to 1.10 percent: Refines the grain, contributes to the toughness and stability of the edge.
- Manganese (Mn) .15 to .45 percent: It contributes to the strength, wear resistance and structure of the grain. It helps with hardenability and tensile strength and increases the workability of steel.
- Silicon (Si) .10 to .40 percent: Contributes to strength. Like manganese (but to a lesser extent), it increases hardness and strength. But only a small amount is needed, as too much silicon can lead to cracking problems.
- Phosphorus (P) .03 percent: In very small quantities increases strength and hardness. You should not have too much phosphorus, as it makes steel brittle. But here you have just enough that helps to increase workability and tensile strength.
- Sulfur (S) .03 percent: Increases workability. Why so little sulfur? Too much and it hurts steel. That is why it is generally considered an impurity. But this very small amount can help with impact resistance, ductility and workability.
- Iron (Fe) is the balance of steel composition.
Common uses of steel D2
The high hardness of D2 steel is ideal for production equipment.
D2 steel is also good for making knives.
In addition to making knives, D2 steel is good for:
- shredders for tires
- forming moulds (for handling sheet metal)
- helicopters for scrap
- hydraulic punches
- Cutters
Pros and cons of D2 steel
For
- It remains sharp for a long time so there is less need to sharpen it
- A fair amount of corrosion resistance can withstand daily blade exposure
- Decent amount of toughness (can survive high drops or a similar amount of stress)
- Cheaper than knives in its class with almost similar hardness
- Flexible enables the use of industrial-grade tools or equipment
Against
- D2 steel cannot compete with knives from the premium range (the price allows for accessibility)
- Knives are difficult to sharpen when they are beveled (it needs diamond abrasives, belt sanders, water sharpeners like the Tormek)
- The thread of the knives chips when used to hit (do not hit hard objects using the edge!)
Is D2 steel good for knives?
If you want the blades to stay sharp for a long time, then yes, D2 steel is a good material for knives, and you will definitely sharpen them less frequently than carbon alloy blades.
I recommend this cheaper alternative if you are looking to spend less because what makes the D2 exceptional is its price.
True, it may not be on par with other premium knife materials but it is worth investing if what you are looking for is that the knife thread does not wear out with every use.
Some may not like the patina or stain that is generated on a D2 steel but as with any tool, taking care of it is key.
I tell you this only if you do not like the rustic look, used on a steel knife D2 when “getting old”.
Hardening of Steel D2
Steel D2 Hardening
Preheating temperature: 650-750°C.
Austenitizationtemperature: 990–1050°C, but usually 1000–1040°C.
| Temperature , °C | Soaking time Min. | Hardness before tempering |
| 990 | 60 | ca. 63 HRC |
| 1010 | 45 | ca. 63 HRC |
| 1030 | 30 | ca. 63 HRC |
Means of hardening
• Oil (Only very simple geometries)
• Vacuum (high-speed gas)
• Forced air/gases
• Tempera bath or fluid bed at 180–500°C, then cooled in air.
Steel D2 Tempering
Temper immediately after quenching.
Keep at temperature for 1 hour per inch (25.4 mm) thick, minimum 2 hours, then cool to room temperature.
The typical tempering range is 180 to 210ºC. Double tempering is recommended.
| Temperature ,°C | 150 | 200 | 250 | 300 | 350 | 400 |
| Hardness,HRC | 62-61 | 61-60 | 60-59 | 57-56 | 56-55 | 56-55 |
Hardness of steel D2
Key feature of D2 steel is hard,it has an air-hardening, high-carbon and very high-chromium composition that makes this high-end knife steel with a hardness in the range of 55 to 62 HRC.
Properties of steel D2
You can expect the following features when you have a knife made of D2 steel:
- Fantastic edge keeping: This is not really surprising, if you consider the hardness of D2 steel. The sharp wire will remain sharp for quite a long time, when the other blades have already blunted.
- Difficult to sharpen: This is the main disadvantage of hardness, though. We put it at the top of this list of properties because you need to prepare for this problem. D2 steel is extremely difficult to sharpen. You’d better be an expert in sharpening, otherwise you need to have an expert sharpen your D2 steel blade for you.
- Not really stainless steel: It doesn’t have enough chromium to technically qualify as stainless steel, but it’s close. So, for corrosion resistance, stainless steels will work better than D2 steel. But compared to other steels that are not stainless steels, D2 steel resists corrosion much better than anything else.
D2 equivalent or alternative steels
Now we know that D2 steel can withstand wear for long periods but how does it fare compared to other types of steels used in cutlery?
We check if D2 is better or worse than 440C, S30V, AUS8 or 1095.
Steel D2 vs 440C
Let’s talk about corrosion, and the 440C resists corrosion well, and there is a tendency in steels for corrosion, if tool steel has a lower hardness, it will better withstand corrosion.
Steel 440C in this case has a lower hardness, so it is more resistant to chemical wear.
D2 has better edge retention, you won’t need to resharpen a D2 knife as often as you would with the 440C.
But the D2 will lose sharpness compared to the 440C.
The advantage of “soft” knife steels is that they are easier to sharpen.
Steel D2 vs S30V
S30V steel produces steel using powder metallurgy.
The finer carbides of the S30V will provide excellent toughness and this allows an S30V to have an even distribution of toughness.
The more complex production process of S30V steel also means that it is more expensive.
D2 steel has a more simplified process because D2 production does not require powder metallurgy, so it is cheaper.
Although the D2 has a decent hardness, it is almost at the same level as the S30V.
In this case, D2 approaches S30V.
The only difference is the quality of the material.
D2 Steel vs. AUS8
AUS8 steel is like 440C as it is also made of stainless steel.
D2 steel scores higher on the hardness scale despite the extra vanadium on AUS8.
The extra vanadium on AUS8 increases corrosion resistance.
Robustness is also an advantage in the AUS8.
D2 gets better edge retention thanks to its innate hardness and for this there will be a small difficulty in sharpening the D2 blades but there is the advantage is that re-sharpening is less frequent.
D2 blades will be sharper for longer.
D2 Steel vs 1095
1095 steel is a carbon alloy, and the advantage of carbon alloys over regular tool steels is the ease of sharpening.
Alloy 1095 can cut sharper.
The problem with carbon alloys is their inability to withstand wear.
D2 steel has carbide inclusions larger than 1095 and this is both a weakness and a strength.
D2 steel will withstand wear longer than a 1095 but a 1095 steel is stronger due to finer carbide inclusions.
That is why D2 steel knives sometimes chip.
Conclusions
The strength, hardness and wear resistance of this steel gave it a reputation in the USA that employed it in the creation of objects used in the 40s for the Second World War;
Even today it is used by many makers to make a unique and strong knife. Once it is hardened it becomes really hard to work.
Some major knife companies that use D2 steel are:
- Brous Blades,
- Lion Steel Knives,
- KnifeArt Knives
- various other manufacturers of high-end knives
I recommend you try it if you want a Hardness of 58-62 HRC in addition to the characteristic of being “semi-stainless” – it is not stainless steel, but still has a considerable resistance to oxidation.
D2 steel knives are inexpensive but still have good wear resistance and have excellent wire tightness.
Most D2 steel knives are easy to manufacture.
Get ready to consume the tapes because once hardened to make the finish it will be a nice adventure!
Are You Experience?
Andrea
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