Tool steel D2 has very good characteristics, although it cannot be called completely stainless. There is not enough chromium in it in order to not be exposed to rust, a minimum of fourteen percent is needed. However, D2 steel justifies its characteristics with very good (compared to competitors) anti-corrosion properties. It is much harder than them and therefore keeps the sharpening excellent. According to the characteristic, D2 steel is much less rigid, it is difficult to sharpen a knife from it, for this purpose a special master is required.
The choice
When choosing a pocket knife, they always pay attention primarily to the type of steel that is used to produce the blade. Its quality depends on its use. The characteristics of D2 steel show that a knife made of such a material will be good to use. After all, what is steel? It’s just an alloy where iron, carbon and alloying additives coexist, improving its basic properties. It is additives, heat treatment and rolling that distinguish different steels in the manufacture of products. There are five main characteristics in total. Reviews for D2 steel say that it does not correspond to all five, nor any other steel.
1. Hardness, resistance to impact. Metal deformation is measured according to the Rockwell method (non-destructive hardness test).
2. Rigidity and resistance to damage (chips and cracks). You need to know that the harder the steel, the less rigidity it has. Reviews describe the steel characteristics of D2 in this way - very hard, and the rigidity is insufficient.
3. Wear resistance to adhesive and abrasive effects. Here, the steel for the D2 knife receives the best characteristics, because the harder the steel, the more wear-resistant. But this property also depends on the chemical composition. The hardness characteristics of D2 steel are comparable to the characteristics of wear resistance, since tungsten carbide is sufficient in its composition.
4. Corrosion resistance and resistance to rust, which from salt and moisture appears almost always. The steel specifications for the D2 knife at this point are not too enthusiastic.
5. The stability of the edges of the product from "blockages", that is, how long the blade of such steel will be sharp when used. Here, the characteristics of the D2 steel grade are excellent.
Compromises
Even in the best steel it was impossible to combine all the highest indicators of these characteristics. The best steel alloys for knives are obtained only by using a compromise, that is, balance, when the hardness is correctly combined with the rigidity. The characteristics of the D2 steel brand indicate that a good balance has been achieved here. An extremely solid blade can be made, but it will become brittle, even if it falls, it can break into pieces. And if you do the opposite and achieve the greatest rigidity of the blade, it will be flexible, but the sharpening on it will go away almost immediately. According to the characteristics of the blade of D2 steel, it was out of competition for a very long time, since the wear resistance of such steel is extremely high.
The most famous brands that make blades used it in their work. Corrosion such a brand lends itself very weakly, less than the rest of carbon. Keeps sharpening for a very long time, and this is one of the main advantages of such products. However, analogues have long appeared that can fight for the championship. For example, High Carbon or 20, a much more carbon version of the D2 steel shown in the photo. Their characteristics are very similar: high content of chromium and carbon, excellent cutting properties, high resistance of the edge of the blade. Today, manufacturers in many countries make extensive use of this steel option for the production of knives - to the best of their durability, storing sharpening for a long time (in addition, it is much easier to grind and sharpen them), and their corrosion resistance is simply excellent.
Comparative characteristics
Types of steel D2 reviews are not only received from the manufacturing country - the USA, since such an alloy is used not only for knives, even high-speed cutters are made from it. Corrosion resistance is not one hundred percent, however, this alloy surpasses other carbon steels in this indicator. In addition to iron, 1.50% carbon, 0.60% manganese, 0, 60% silicon, 12% chromium, 1.00% molybdenum, 1.10% vanadium, 0.30% nickel. The strength of this steel is very high. In the characteristics, the properties of D2 steel are described as follows: the hardness range for the production of knife blades is determined in the range of 57-61 HRc, the sharpness of the cutting edge lasts a very long time. Such steel is used quite widely by leading companies specializing in the production of blades. These are Pohl Force, BENCHMADE, BROUS BLADES and many others. However, there are analogues of steel D2. Their types are produced in Russia (X12MF steel) and Germany (X155CrVMo12-1 steel).
For comparison, consider another American-made alloy - the same high-strength, wear-resistant tool powder steel, which is produced by the metallurgical company Crucible Materials Corporation. From it you get a no less good blade for a knife. Steel D2 has excellent characteristics, but steel CPM 3V is no worse. It is intended for the manufacture of tools that are most resistant to chiping (when the steel is crumbling) and fracture. And the CPM 3V has no less wear resistance on the cutting edge. The composition of this steel slightly changed the proportions: carbon is 0.80%, and chromium is only 7.50. Molybdenum - 1.30%, vanadium - 2.60%, silicon - 0.90%, manganese - 0.40%. Such an alloy is superior in impact strength not only to the steel characteristics for the D2 knife. Reviews say that high-grade alloys A2, CPM M4, Cru-Wear are also inferior in this quality to CPM 3V. In addition, it better holds chopping and power loads. This is one of the most viscous and mechanically strong steels with an excellent balance of strength, wear resistance and toughness. And she has no analogues.
D2 steel reviews, specifications
Knives made of high-carbon steel D2 are the most popular, and this steel itself is today one of the most popular. Most manufacturers consider it the best combination for the manufacture of blades due to its combination of properties. As already mentioned (and almost everyone mentions it in reviews), twelve percent of chromium does not make this steel completely stainless, however, none of the other high-carbon corrosion resistance can be compared with D2. She also holds sharpening better than others, she has a high impact strength. If hardening was carried out correctly, such a knife will serve its owner faithfully.
The blade practically does not rust, but it is recommended to wipe it with a dry cloth from time to time, and also not to leave it in wet places. They use D2 in the automotive industry, they make sharp razors and even blades of jet turbines from it. Most often, such steel goes to metalworking tools. It is durable and does not lend itself to polishing. Leading blade makers use D2 steel. These are Bob Dozier (Bob Dozier), Tomoyuki Nemoto (Tomoyuki Nemoto), Suzuki Yoshiro (Suzuki Yoshiro), Kiku Matsuda (Kiku Matsuda) and the American William Henry Studio. Many well-known companies in Japan and the USA make knives from high-carbon chrome tool steel D2.
The properties
Steel D2 is used for blades that are used in hunting equipment and camping, housewives like these knives in the kitchen, and EDC knives are produced (everyday use), even axes and machetes. This steel grade has properties that will satisfy any need, since the material of the cutting part of such products with proper processing is beyond praise. At a height, literally all the properties: viscosity, elasticity, resistance to rust. The blade of steel D2 perfectly holds the sharpening, it is hard and adapted to fine-tuning the sharp edge. This steel is so good that it does not cease to be popular, despite some difficulties in processing it and not at all low cost.
Absolutely all the positive properties cannot be combined in itself by any steel. But D2 is as close as possible to this. Carbon steels have a fine-grained structure, and therefore D2 is not so difficult to sharpen, but such steel is not very resistant to corrosion. D2 contains an almost full amount of chromium, which stainless steel is supposed to have, and therefore it differs significantly from other types of carbon steels for the better. Only blades made by the powder metallurgy method are superior to it in this regard, which are even less susceptible to corrosion and retain their cutting properties even better. But they have their own characteristics: fine-tuning the cutting edge is difficult. Therefore, the process of powder steel processing itself is laborious and much more expensive.
Carbon steel
Steel, from which a variety of knives can be made, is usually divided into two groups. Carbon, judging by the name, contains carbon, and it should be at least 0.5%, since steel for knives must necessarily tolerate hardening well. But if carbon is more than 1.7%, such an alloy will not succumb to forging. In almost all carbon steels, there are no other alloy constituents: molybdenum, vanadium, chromium, manganese, and the like. Therefore, they are very simple in heat treatment, and this is their main property. The heating range can be very wide, and almost any mistakes of the master can be corrected during the forging-hardening process. Another property of carbon steel is that it is easy to process in an unhardened state - you can cut, drill, grind and much more. It is easy to sharpen to an extremely acute condition.
But carbon steels also have some disadvantages. The main one is low corrosion resistance. Skilled craftsmen minimize this error by polishing the product to a mirror shine. Such steel needs constant and thorough care: after each operation, the blade is cleaned of foreign products (including dirt), and then slightly greased with oil. However, it should be noted that even the most careful attitude to the blade will not prevent changes. A gray coating and spots are formed on the surface of the blade if it comes in contact with any acids. It can be any fruit and many vegetables, such as tomatoes. Fatty acids are also bad for carbon steel. Upon contact with them, the alloy changes color, becomes dull. Even fried meat is better not to cut with such a knife. But all this does not threaten steel D2, in any case, far from to the same extent. This alloy is rich: it contains a lot of chrome and all other components on the list.
Alloy steels
Tool alloy steels are an ideal material for making blades. In the characteristics they have a lot of positive properties: if chromium is more than 14%, they are resistant to corrosion, retain cutting properties and are quite hard. Alloying additives can be different depending on the purpose, on the purpose of the future knife. Here it is necessary to say separately about steels made by the PM method (powder metallurgy). They are much more wear-resistant in comparison with the standard, perfectly hardened, while maintaining good viscosity. All these three properties are basic, and they are what they want to achieve in the manufacture of knife steel. Alloy steels are a priority for use in knife production. PM technology (when powder metallurgy technologies are used) is quite expensive. The technological process takes place with the atomization of the constituent elements in a molten state in an inert gas medium or in vacuum, then the pasty mixture is pressed under pressure and at high temperature.
Thus, it is possible to combine the elements of the alloy into a single composition. And if you simply melt and try to mix them in high concentration, this is unlikely to work out quite effectively. As salt does not dissolve in a supersaturated solution. And in steel, the powder method provides many advantages. Hard carbides turn into the smallest almost identical balls, the steel gets a fine-grained structure, and therefore it is excellently polished. The toughness of this steel is very high, as well as excellent tensile strength. Blades made using powder metallurgy are equipped with a much larger tensile strength for a broken blade. No ordinary steel grade can be compared with such an alloy in this quality. In addition, these alloys can be subjected to any degree of hardening, which means that you can get a very thin blade. Production is labor-consuming, PM steel is more expensive than just cast, but the quality is not better as an example.
Alloying elements
The wear resistance and toughness of this steel grade significantly complicate its processing, abrasive belts and tools wear out much faster, which also affects the cost of the product from PM super steel. But the alloying elements added to the composition are of great importance . Iron can only be hardened if it is combined with carbon. The amount of it can be different, it depends on the grade of steel that you need to get. In addition to carbon, the presence of which is necessary, good steel can have a number of added elements that will ennoble it and fundamentally change its properties.
Carbon gives stiffness to steel and, together with iron, forms carbides - these are very solid metal-carbon compounds. Chrome, as already mentioned, will give this alloy resistance to corrosion. If this element in the composition is more than 13%, the steel will turn stainless. But this is not all the benefits brought by the addition of chromium. With its presence, steel gains wear resistance and hardness. Manganese promotes the formation of a granular structure in the material of the blade, which significantly increases the strength of the product, especially with regard to tools. Silicon also accompanies the fortification of steel, is used in forging. Vanadium (as well as tantalum, molybdenum, nickel, tungsten, cobalt) increases stiffness and wear resistance.
Popular steel grades
An excellent combination of hardness and resistance to corrosion is demonstrated by products made of modern 440C chrome steel, from the entire group of steels of this brand it is most often used for the production of blades of the best folding knives in the world, since it is the hardest. In addition to iron, it contains 1.10% carbon, as much as 17% chromium, 1% silicon and manganese, 0.75% molybdenum, 0.04% phosphorus, and 0.03% sulfur. This composition gives the cutting edge good durability, it does not dull for a long time and is quite easy to sharpen. For a long time, 440C steel was the quality standard for knives, it was considered the most balanced in terms of properties. Her prevalence in the world is very high, her reputation is positive. However, from the 440th group, this steel is the most expensive. Analogs exist in Japan (AUS-10), in France (Z100CD17), in Germany (X102CrMo17), in Austria (N690) and in Russia (95X18).
Duratech CV20 martensitic high-alloy powder stainless steel (CPM 20CV) is manufactured by Crucible Industries LLC (USA). As part of it - an increased volume of vanadium carbides, therefore, it has few rivals in terms of wear resistance. The high chromium content provides corrosion resistance. By the way, this brand has the highest chromium content in modern steels. Carbon - 1.90%, chromium - as much as 20%, molybdenum - 1%, vanadium - 4%, tungsten - 0.60%. CPM 20CV steel, hardened at 58 HRc, is considered the most balanced in terms of resistance to wear and corrosion, as well as strength. In this, it surpasses the 440C, CPM Rex M4, CPM 9V and many others well-known for their quality. The distribution of carbides during the manufacturing process is more subtle and uniform, so the viscosity improves, sharpening and processing become easier. Hardening at 61-63 HRc when the blades are made increases resistance to stress. Steel CPM 20CV is used for the production of not only serial, but also top-end, designer knives. This brand is very popular in Russia. Analogs exist only in the USA (CPM S90V) and in Austria (M390).
Comparison with D2
Premium steel CPM S90V (420V) is a stainless martensitic powder steel with exceptional wear resistance by adding a certain amount of carbon and vanadium. It is released by the metallurgical company Crucible Industries LLC (USA). Particularly high vanadium content in this steel forms solid vanadium carbides, not chromium carbides, and therefore the cutting blade has the highest wear resistance, especially when compared with similar tool steels D2 and 440C.
Free chromium is also present in the composition, which makes the blade much more corrosion resistant than D2 and 440C steels. D2 includes only 12% chromium, and CPM S90V - 14%. In addition, it contains as much as 9% vanadium! Carbon - 2.30%, molybdenum - 1%. There are no more alloying additives. True, you will have to tinker with sharpening such a blade, it is much more difficult to work with steel CPM S90V than with 440C or D2. Serial knives are made from it quite rarely, mainly copyright and exclusive works. There are analogs in the USA (CPM S60V) and in Austria (N690).