AT514133B1 - Ring-shaped tool - Google Patents

Abstract

Ring-shaped tool (1) with at least one radially outwardly directed working area (4) with high wear resistance and an axis closer clamping part (5), in particular roller bit or cutting ring for rock, in particular for tunnel boring machines, made of a material which consists of an iron-based alloy as a matrix with embedded hard material particles is formed, wherein the hard material particles of carbide and / or nitride and / or oxide and / or boride, optionally formed as carbonitride or oxycarbonitride with boron at least one of the elements, or in a mixed form of the elements, groups 4 and 5 of the Periodic Table and have a density at room temperature of greater than 7400 kg / m3, preferably greater than 7600 kg / m3, as well as processes for its preparation.

Description

description

RINGTONED TOOL

The invention relates to an annular tool with at least one radially outwardly directed working area with high wear resistance and an achsnäheren clamping part, in particular a roller chisel or cutting ring for rock, especially for tunnel boring machines.

The invention further relates to a method for producing annular tools with at least one radially outwardly directed working area and an axially closer clamping part, in particular roller bits or cutting rings for rock, in particular for tunnel boring machines, formed from an iron-based alloy as a matrix, in which hard material particles, such as carbides and / or nitrides and / or carbonitrides and / or borides, are optionally incorporated in a mixed form of the elements of groups 4 and / or 5 of the periodic table.

STATE OF THE ART

Drilling rigs for rock formations or rock and the like, are usually equipped for larger diameter with annular tools, which have an outwardly directed working area and roll under pressure on the rock bottom and thereby cause a removal or a break of this.

Tunnel boring machines, for example, have a large dish-shaped tool holder, in which a plurality of so-called roller bits or cutting rings are mounted rotatably mounted. When propulsion of the tool holder is rotated and pressed with high force to the mountains, the same at different radii arranged roller bits in the respective areas are rock breaking effect and the removed rock or the so-called cuttings is discharged behind the tool holder.

According to the mechanical requirements, the annular tool should have a tapered, radially outwardly directed working area, in this particular high wear resistance and high hardness and high toughness of the material.

In most cases, the raw tool part is shrunk onto an axis, which inevitably tensile stresses arise in the clamping range, which are superimposed in the heavy, the hard rock breaking operation, respectively the required compressive stresses of the material and give no substantially stationary loads of the tool material.

Roll chisels should therefore have a working area with the highest possible wear resistance and a clamping range with sufficiently high hardness and high toughness and overall superior breaking resistance of the material with varying mechanical stress, because a failure of a tool causes costly repair work with a stoppage of the drill.

The cutting rings are usually made of a tool steel. The shaping is generally carried out by a forging process, wherein the desired material properties are achieved by a subsequent heat treatment. It is known to the person skilled in the art that the greatest possible wear resistance in tool steels can only be achieved with a high hardness of the structure. Here it must be accepted that with increasing hardness the tenacity of the structure decreases. In order to achieve the best properties for tool steels in terms of hard use as a cutting ring, a compromise between maximum wear resistance and high toughness must be made.

Various attempts have been made to extend the service life of the cutting rings by combining extremely wear-resistant materials with solid but tough materials. DE 10 2005 039 036 B3 describes, for example, a steel roller chisel which has welded segments in the working area, these tungsten carbide hard metal particles containing. From JP 2000001733 A a similar cutting ring is known, which has a hard metal ring applied on the outer circumference of a base body made of ductile iron. Furthermore, from the writings JP 2007138437 A, GB 1188305, GB 1379151, DE10300642 A1 and DE 101 61 825 A1 cutting rings for tunnel boring machines are known which have arranged on the outer periphery segments, or cylindrical and otherwise specially shaped parts made of hard metal, which by soldering , Pressing or pouring be connected to the body. CA 2 512 737 A1 also describes a cutting ring in which segments made of hard metal are axially clamped between two disks. All of these known approaches to solutions involve either a very complex and difficult production or lead for example by high thermal stresses during use or by the softening of the solder for premature failure of the cutting rings in use. In JP 59144568 A, a manufacturing method for cutting rings is described, in which a melt containing tungsten carbide-based cemented carbide particles is poured into a rotating mold, whereupon the hard metal particles concentrate in the outer region of the cast body. This method has the disadvantage that the hard metal particles added to the melt are partially dissolved by the melt and, during solidification, can form undesirable, brittle microstructural constituents in the microstructure of the tool. Also, the minimum size of the added cemented carbide particles is limited by the dissolution process.

OBJECT OF THE INVENTION

The invention has for its object to provide a generic, annular tool which allows for hard, rock-breaking operation an increased service life.

Furthermore, it is an object of the invention to provide a method of the type mentioned for the production of annular tools, which have the respective stresses according to an optimal material structure.

The above-mentioned object, to provide a generic, annular tool, which allows an increased operating time in hard, rock-breaking operation, is achieved by the tool consists of a material consisting of an iron-based matrix alloy with embedded in this hard material particles is formed. The hard material particles may be formed of carbide, nitride, oxide or boride, but also as compounds of these, such as carbonitride, carboboride or Oxikarbonitrid with boron content. Depending on the application, it may be advantageous that mixtures of these different types of hard materials are included in the tool. The metal content in the hard material particles essentially comes from groups 4 and 5 of the periodic table (Ti, Zr, Hf, V, Nb, Ta), whereby here too only individual elements from these groups or mixtures thereof can be contained in the hard materials. Compared with the hard materials used in iron metallurgy, the metallic components of which come from Group 6 of the Periodic Table (eg tungsten carbide), have hard metals from Group 4 and 5 metals the advantage that these in common in practice melting and casting temperatures of iron-based alloys up to 1650 ° C have only a low solubility in a molten iron melt.

It is known that hard substances which are formed or precipitated during the solidification of an iron melt base and during the further cooling of the resulting workpiece, preferably form eutectic microstructures or precipitate at grain boundaries. The hard materials thus formed can significantly reduce the toughness of the structure. The advantage of the low solubility of the above hard materials in a molten iron melt lies in the fact that on the one hand large amounts of these hard materials may be contained as solid particles in the melt, on the other hand, only a small amount of additional amounts in the solidification of the melt and in the further cooling of the workpiece Hard material particles are formed or eliminated in the microstructure. These small amounts of brittle hard materials negatively affect the toughness of the structure only to a small extent. However, these can increase toughness even when the precipitated particles are sufficiently fine to reduce grain growth of the matrix during heat treatment.

In order to achieve a high wear resistance and long service life of the roller bits, both a minimum proportion of hard particles in the structure should be present as well as the hard particles so inhomogeneous be distributed in the cutting ring, that is a high proportion of this in the radially outward working area of the roller chisel located. For a volume fraction of the wear-resistant working range of about 8% by volume (% by volume) considered sufficient, a proportion of hard material of at least 5% by volume, based in each case on the entire workpiece, has proven suitable. At least 8% by volume of hard material particles are necessary if heavy working conditions are foreseen for the cutting ring. The possible service life of the roller bits can be increased with a larger volume proportion of the work area. Thus, the proportion of the work area can be increased to about 25% by volume and above, to allow long operating times in difficult operating conditions.

The desired distribution of the hard particles in the cutting ring is achieved when their density is higher than the density of the melt and they move so in the centrifugal casting process to the outside. Experiments have shown that good results are already achieved when the density of the hard material particles at room temperature is greater than 7400 kg / m3. A desired, high concentration of the hard material particles in the work area is achieved if they have a density greater than 7600 kg / m 3 at room temperature. Hard materials with this density are, for example, carbides, nitrides and carbonitrides of niobium, which have proven themselves in tests. It has also been shown that a slight addition of vanadium to these niobium hard materials can favorably influence the growth and the properties of the particles, but with the addition of vanadium the density of the particles decreases. A ratio of Nb atomic% / V atomic%> 5 should in any case be complied with for niobium-vanadium mixed carbides, which may optionally also be carbonitrides. Higher concentrations of these particles in the working range are achieved with a ratio Nb atom% / V atom%> 10.

It is known to the person skilled in the art that the wear resistance of a microstructure depends not only on the hardness of the matrix and the embedded hard material particles, but also on their quantitative ratio, but also on the size distribution of the hard material particles. In the following, all structural constituents are understood as a matrix, which are not the above-mentioned hard material particles. If the particles of hard material are too small, they can be removed from the matrix in the form of entire particles as a result of their fearsome wear, without particularly increasing the wear resistance. However, if the particles are too large, they may break under the high pressure load during the rock-breaking operation and thereby also not increase the wear resistance sufficiently. In the present case of the roller bits, it has been found that best results can be achieved if at least 60% by volume, preferably at least 75% by volume, of the hard material particles having a size of less than 70 μm are formed.

In addition to the properties of the hard material particles and the properties of the matrix are of crucial importance to achieve a high wear resistance in the working area of the roller chisel. In particular, the properties of the matrix are crucial in order to allow a sufficient toughness of the structure both in the working area, as well as in the clamping area. The properties of the matrix are mainly based on their chemical composition and possible heat treatment. Carbon is the most important alloying element and, above all, affects the hardenability of the steel, with about 0.28 wt.% C being considered as the lower limit for sufficient hardenability of the steel for the present application. With a carbon content of more than 1.2 wt .-% in the matrix, a carbide network can form in the structure, which reduces its toughness. Silicon increases the strength and the wear resistance but also the melt pourability, but should not exceed 2% by weight in the matrix. Manganese reduces the critical cooling rate to form the martensite and, with a sufficient amount of up to 2% by weight, enables air-hardening of the cutting rings. By higher manganese contents up to 25 wt .-%, the solubility of carbon in austenite can be significantly increased and the conversion properties of the austenite be influenced by cooling or mechanical Beschu chung. With manganese contents of up to 25% by weight, the carbon content in the matrix can also be up to 2.3% by weight. Like manganese, chromium also increases the hardenability of the steel and forms secondary and tertiary carbides which are precipitated from the austenite and increase wear resistance, with excessive chromium contents resulting in a chromium carbide network in the structure. The chromium content should therefore not be higher than 6.0% by weight. Like manganese and chromium, nickel also promotes martensite formation and, in addition, increases the toughness of the matrix. For nickel, a content of 2.5% by weight appears as an upper limit in the matrix to achieve the necessary properties as sufficient. To set a low critical cooling rate, a combination of Mn, Cr and Ni has been demonstrated. Molybdenum increases the strength of the matrix up to about 2.2% by weight and increases the wear resistance through the formation of carbides. Tungsten forms together with Nb and V mixed carbides and mixed nitrides and can thus increase the density of these hard materials. However, the content of W in the melt is adjusted so that after ejection of the primary hard materials formed in the matrix only a content of max. Contains 1.5 wt .-%, otherwise together with Mo may form a network of W-Mo mixed carbides. For this reason, 1.5xMo + W should not be more than 3.5% by weight. Due to the high affinity of Nb and V to C or N of these in the matrix remain only small amounts of less than max. 0.8% by weight back. Like Nb and V, Ti, Zr, Hf, and Ta also remain low in the matrix. Cobalt can be included in the matrix to increase the heat resistance in particularly high-stress cutting rings up to a content of 3% by weight. For the deoxidation of the melt is often added AI, which can remain partially dissolved in the matrix after solidification. Higher levels of Al can reduce the density of the melt and thus increase the density difference to the hard material particles. An Al content of up to 3% by weight in the matrix is possible.

As a base composition for the matrix are particularly suitable alloys of alloyed tool steels, as described in the standard DIN 10020. Both cold work tool steels, hot work tool steels and high speed steels can be used as the base composition for the matrix. To avoid eutectic carbides, it is sometimes necessary to reduce the carbon content of the high-speed steels compared to the standard composition. With these matrix alloys, by a suitable heat treatment, which generally consists of a hardening process and a tempering process, the hardness required for a trouble-free use of the cutting rings of at least 44HRC can be achieved. It has been found that a particularly good wear resistance is achieved if the matrix of the cutting rings has a hardness of 50HRC and above. This hardness is required when drilling in hard, particularly abrasive rock formations. The heat treatment of the cutting rings must always be adapted to the particular application of the application in order to achieve a balance between hardness and toughness of the structure.

If the matrix composition selected according to a manganese hard steel, so the advantage of a particularly tough and impact-resistant basic structure can be used together with a pressure-hardening and thus wear-resistant surface. In "Houdremont, Handbuch der Sonderstahlkunde, Springer Verlag, 1956" and other literatures, such manganese hard steels, which according to their inventor are also called Hadfield steels and according to their structure are austenitic manganese tool steels, are described, which have a manganese content of about 8 wt. % to 15% by weight, in exceptional cases 6 to 25% by weight, and a carbon content of about 0.8 to 2.3% by weight. The ratio of% by weight of Mn to% by weight of C is At about 10: 1, manganese hard steels, after heat treatment, are characterized by a metastable, very tough austenite structure, which can cause the metastable austenite to turn into a hard and wear-resistant martensite due to compressive stress on the surface Depending on the proportion of Mn and C in the steel and their quantitative ratio to each other, the conversion behavior can be influenced Due to the hard, martensitic surface alone, the load during use may be sufficient. Is the pressure load during use not enough to the required

To cause transformation of the structure in the region of the surface, the surface area to be hardened can be hardened, for example by hammering or another mechanical treatment, even before use. The composition of the matrix alloy can also be adjusted so that the surface or the entire tool body can be at least partially converted into martensite by a cooling below room temperature, preferably by means of liquid nitrogen.

There may be described above roller bits or similar annular tools, which contain at least one radially outward working area and an achsnäheren clamping part, and of an iron-based alloy as a matrix, in which hard material particles, such as carbides and / or nitrides and / or carbonitrides and / or borides, optionally incorporated in a mixed form of the elements of Groups 4 and / or 5 of the Periodic Table, can be prepared by, in a first step, melting a base alloy, for example in an induction furnace, and to a temperature of 10 -30 ° C to 1630 ° C ° C is heated. This base melt is used to bring most of the alloying elements for the subsequent finished alloy in the melt.

Depending on the desired matrix composition and, depending on the choice of execution of the subsequent second step, the base melt may have the following composition in% by weight:

Carbon (C) to 2.5

Silicon (Si) 0.01 to 3.0

Manganese (Mn) 0.05 to 28.0

Chrome (Cr) to 9.0

Nickel (Ni) to 4.3

Molybdenum (Mo) to 3.5

Tungsten (W) to 2.2 (1.5xMo + W) to 5.1

Vanadin (V) to 6.0

Niobium (Nb) to 35.0

Aluminum (AI) to 3.5, if necessary

Titanium (Ti) to 2.0

Zircon (Zr) to 3.0

Hafnium (Hf) to 1.0

Tantalum (Ta) to 5.0

Cobalt (Co) to 3.5 Iron (Fe) and impurity elements as balance.

Are in the base melt already the metallic components of the later to be formed hard material particles (elements from groups 4 and 5) and at the same time the proportion of C, N and B kept as low as possible, so in a second step carbon and / or nitrogen and / or boron introduced into the base melt, whereupon these elements with the elements of group 4 and / or 5 of the periodic table already in the base melt to hard particles which have a higher density than the melt connect. The hard materials formed have the structure Mx (C + N + B) y, wherein the sum of carbon, nitrogen and boron in the hard materials formed is between 0.4 and 0.55 atomic parts, or the ratio x: y is between 1.5 and 0.8. The amount of alloyed carbon should be selected such that a carbon content of 0.3 to 2.3% by weight remains in the residual melt. This provides sufficient carbon for the formation of martensite in the matrix during the subsequent heat treatment. The amount of the other alloying elements, except those of the 4th and 5th group, depends on the desired properties of the matrix surrounding the hard material particles, wherein the formation of a eutectic carbide network to achieve the highest possible toughness should be avoided. Particular attention should be paid here to the heat treatment properties of the matrix.

A rapid formation of the hard materials with low wear of the melting vessel is obtained when the temperature of the base melt is maintained between 1550 ° C and 1630 ° C. The alloying of carbon, nitrogen and boron can be carried out by solid substances such as coke, high carbon ferrochrome, silicon carbide, ferro-nitrogen and ferroboron or by addition of carbon and / or nitrogen and / or boron-containing melts or gases. This component or components may or may also contain other alloying elements. Depending on the carbon, nitrogen and boron content of the added component or components, very large amounts of these may be necessary to achieve the desired carbon, nitrogen and boron levels in the final melt. The amount of added carbon, nitrogen and boron carriers can thus also be significantly greater than the amount of the base melt, with which the alloy elemental proportions in the base melt can assume very high levels, e.g. Niobium up to 35% by weight.

The melting of a rich in the elements of the 4th and / or 5th main group alloy with low levels of carbon, nitrogen and boron has the advantage that the ferroalloys, on which in general the elements of the 4th and 5th Group are alloyed, dissolve quickly. If the contents of carbon, nitrogen and boron in the melt are too high, a layer of hard material can form on the surface of the ferro alloy pieces used, which severely hampers the dissolution. It has been shown in experiments that the proportion of carbon in the base melt in the above case should be less than 0.6 wt .-%.

It is also possible to adjust in the first step, the composition of the base melt such that it does not contain the elements for forming the hard material and in the second step, the hard material particles, by means of a solid or liquid, metallic pre-melt or by means of a similar mixture Metal and hard particles, added and homogeneously distributed in the base melt. These hard material particles may be carbides and / or nitrides and / or oxycarbonitrides and / or borides, optionally as carbonitrides and / or oxycarbonitrides with borane portions, at least one of the elements or in a mixed form of the elements of groups 4 and 5 of the periodic table. The homogeneous distribution of the hard material particles in the base melt can be assisted by mechanical processes, for example by stirring, or also by the injection of gases in the lower region of the melting vessel.

Depending on the composition of the composition and the composition of the formed or introduced hard material particles, it may be advantageous, for example, to prevent oxidation of constituents in the melt, the process steps 1 and / or 2 in the whole or even partially under a protective gas atmosphere or under to perform reduced ambient pressure.

After the homogeneous distribution of the hard material particles in the second step, the matrix melt is poured with the hard material particles contained therein in a third step in a rotating mold and allowed to solidify. Caused by the rotational movement about the longitudinal axis of the mold and thereby acting on the melt and the hard particles centrifugal force, the hard particles migrate outward into the later work area of the roller bit, where they form a very rich in hard materials microstructure. At the same time, a microstructure forms in the interior, which has only small contents of the primary precipitated or introduced hard materials. The resulting proportion of hard materials in the outdoor area is mainly due to the process parameters speed of the mold, the density difference between the hard particles and the melt, the size distribution of

Hard material particles and the cooling rate of the melt in the rotating mold determined. In order to achieve a high concentration of hard material particles in the outer region and thus a high wear resistance, the speed of the mold and thus the force acting on the melt and on the hard particles centrifugal acceleration should be as high as possible. Centrifugal accelerations of 700 m / s 2 and above, measured on the outside diameter of the casting, have been proven. A high density difference between the hard material particles and the melt can be achieved above all by high proportions of niobium, tantalum and hafnium in the hard materials. For cost reasons, niobium-rich hard materials, in particular niobium-vanadium mixed carbides, have proven to be favorable for achieving a high proportion of hard material. In any case, the hard-substance particles precipitated or added in the second step should have a density which is greater than that of the matrix melt at a temperature of 50 ° C. above its liquidus temperature.

The migration of the hard material particles to the outside requires depending on the dimension of the casting different time and to achieve a maximum possible concentration of hard materials in the outer structure, the time between the time of pouring the melt into the mold and the solidification of the melt should be as large as possible. Preheating the mold on several ΙΟΟ'Ό can bring slight advantages here. The speed of solidification can be particularly reduced if the mold as a whole or in parts facing the casting is made of a material which conducts the heat very poorly. Above all, quartz sand and molded materials based on aluminum-silicate ceramics should be mentioned here. Also, a heat-insulating ceramic-based or carbon-based coating on the inside of the mold brings advantages here.

After the casting of the blank, this can be taken to keep the stresses in the ring low, with a temperature of up to 1000 ° C from the mold, balanced in an oven, the temperature over the entire ring and then cooled so slowly be that the matrix structure is in a soft state at room temperature. The cooling rate depends here on the alloy composition of the matrix. If the later conditions of use of the roller bit require it, e.g. drilling in particularly hard rock, so after emptying the blank from the mold this can be brought in an oven to the appropriate forging temperature and then be plastically deformed in the drop forging process in one or more stages. Through this process, the toughness of the structure can be significantly increased. The forging process then includes the controlled cooling to room temperature. Thereafter, the blank may be mechanically removed by e.g. Turning be prepared, followed by a heat treatment of the ring follows. This may, in the case of a matrix composition similar to a tool steel, consist of a hardening process and at least one annealing process. In the case of a matrix composition similar to a manganese-hard steel, a rapid cooling generally takes place after an annealing treatment, in order to achieve a metastable, austenitic structure. After the heat treatment, the mechanical finishing of the cutting ring is followed by e.g. Turning and / or grinding.

Subsequently, the invention will be described with reference to an example carried out.

A pre-melt with 0.28% C, 1.3% Si, 0.9% Mn, 1.34% Cr, 2.2% Ni, 0.1% Mo, 0.8% V and 10.0% Nb was melted in an induction furnace to a temperature of ΙδθΟ'Ό kept at this temperature for 5 minutes and then brought to a carbon content of 2.35% with petroleum coke at the same temperature. After carburizing, the temperature of the finished melt was lowered to 1570C, held there for 3 minutes and then poured off in a centrifugal casting process. As a centrifugal casting mold, a steel mold was used, in which a core of bonded silica was inserted. This core was previously coated on the inside surface with 1mm thick zirconia base size. The casting was removed at about 800'O from the mold and cooled after a compensation phase of 60min in the oven in this room temperature, then preprocessed and brought by hardening and two tempering to a hardness of 53 HRC in the clamping range.

Figure 1 shows an example of a cut annular roller chisel 1 with the cross section 2. The enriched with hard particles Part 3 includes the lying on the outer diameter of the ring 1 work area 4. The clamping area 5 is located on the inner diameter of the ring 1 and contains only a small proportion hard materials.

Figure 2 shows an example of the structure in the working area 4, wherein the hard particles are bright and the matrix are shown in dark. The hard material content is about 20%.

Figure 3 shows, for comparison, the microstructure in the clamping region 5 with only a clotting conditions share of hard materials.

Claims (12)

claims 1. annular tool (1) having at least one radially outwardly directed working area (4) with high wear resistance and an achsnäheren clamping part (5), in particular roller chisel for rock or as a cutting ring for example, tunnel boring machines, characterized in that the tool of a cast Material which is formed of an iron-based alloy as a matrix with embedded hard material particles, wherein the hard material particles of carbide and / or nitride and / or oxide and / or boron, optionally as carbonitride or oxycarbonitride with boron at least one of the elements, or in mixed form the elements, groups 4 and 5 of the Periodic Table, are formed and have a density at room temperature of greater than 7400 kg / m3, preferably greater than 7600 kg / m3. 2. Tool (1) according to claim 1, characterized in that the hard material particles to an extent of at least 5 vol .-%, in particular of more than 8 vol .-%, are present in the tool, wherein the hard material particles on the tool cross-section (2) are distributed inhomogeneous and in the work area (4) have a higher concentration than in the clamping part (5). 3. Tool (1) according to claim 1 or 2, characterized in that the working area (4) has a volume proportion of at least 8.0%, preferably of at least 14.0%, in particular from 20 to 25%, of the tool (1), in which Working range more than 60 vol .-%, preferably more than 75 vol .-%, the hard particles are formed with a size of less than 70 pm. 4. Tool (1) according to one of claims 1 to 3, characterized in that the hard material particles are formed substantially as niobium-vanadium mixed carbides, optionally with a nitrogen content, and a ratio of At .-% Nb to At .-% V greater than 5, preferably greater than 10, have. 5. Tool (1) according to one of the preceding claims, characterized in that the matrix alloy has a chemical composition within the limits of in wt .-% carbon (C) 0.28 to 2.3 silicon (Si) 0.01 to 2.0 manganese (Mn) 0.05 to 25.0 Chromium (Cr) to 6.0 Nickel (Ni) to 2.5 Molybdenum (Mo) to 2.2 Tungsten (W) to 1.5 (1.5xMo + W) to 3.5 Vanadium (V) to 0.8 Niobium (Nb) to 0.4 Cobalt bis 3.0 Aluminum (AI) to 3.0 Optionally titanium (Ti) to 0.2 zirconium (Zr) to 0.2 hafnium (Hf) to 0.1 tantalum (Ta) to 0.25 iron (Fe) and impurity elements as balance. 6. Tool (1) according to claim 5, characterized in that the matrix alloy consists of tool steel having a hardness of greater than 44 HRC, preferably of 50 HRC and higher. 7. Tool (1) according to claim 5, characterized in that the matrix alloy of manganese steel with a manganese concentration of 6 to 25 wt .-% Mn, preferably from 8 to 15 wt .-% Mn. 8. A method for producing annular tools (1) having at least one radially outwardly directed working area (4) and an axially closer clamping part (5), in particular roller bit or cutting ring, formed from an iron-based alloy as a matrix, in which hard material particles such as carbides and / or nitrides and / or carbonitrides and / or borides, optionally embedded in a mixed form of the elements of groups 4 and / or 5 of the periodic table, in particular for producing a tool according to at least one of the preceding claims, characterized in that in a first step, a base alloy is melted and heated to a temperature of 1350 ° C to 1630 ° C and in a second step hard material particles with a higher density than the melt of these are added or formed in this, in a third step, the matrix melt with the hard material particles in a mold for the annular tool rotational movement to d The longitudinal axis is subjected and allowed to solidify. 9. The method according to claim 8, characterized in that in the first step, a base alloy having a chemical composition in wt .-% of carbon (C) to 2.5 silicon (Si) 0.01 to 3.0 manganese (Mn) 0.05 to 28.0 chromium (Cr) to 9.0 nickel (Ni) to 4.3 molybdenum (Mo) to 3.5 tungsten (W) to 2.2 (1.5xMo + W) to 5.1 vanadium (V) to 6.0 niobium (Nb) to 35.0 aluminum (AI) to 3.5 optionally titanium (Ti ) to 2.0 zirconium (Zr) to 3.0 hafnium (Hf) to 1.0 tantalum (Ta) to 5.0 cobalt (Co) to 3.0 iron (Fe) and impurity elements as the remainder. 10. The method according to any one of claims 8 or 9, characterized in that in the second step, the hard material particles by means of a solid or liquid metallic alloy or premelt or by means of a similar mixture of metal and hard material particles having a diameter of the hard particles of less than 70 pm in the liquid base alloy is introduced and homogeneously distributed in this, after which in the third step under rotation in the mold a solidification of the mixture of hard material and a matrix alloy formed from the base alloy and the metal portion of the premelt occurs. 11. The method according to any one of claims 8 or 9, characterized in that the base alloy is melted with a carbon content of less than 0.6 wt .-% C and heated to a temperature of 1550 ° C to 1630 ° C, after which in a second step Addition of the alloying elements carbon and / or nitrogen and / or boron, for example, as a master alloy and these elements with the dissolved elements of Group 4 and / or Group 5 of the Periodic Table in the melt primary carbides and / or nitrides and / or borides and / or Compounds or mixtures of these form, wherein the forming hard material particles have a sum of carbon, nitrogen and boron of 0.4 to 0.55 atomic proportions and a higher density than the melt and wherein 0.3 to 2.3 wt .-% carbon in the liquid metal remains, whereupon in a third Step subjected the melt in a mold for the annular tool of a rotational movement about the longitudinal axis and he is left to rigid, and carried out in further steps, a machining and a heat treatment of the tool. 12. The method according to claim 11, characterized in that the concentrations of the elements of groups 4 and 5 of the periodic table in the base alloy are chosen so that the density of the primary precipitated hard material particles is greater than that of the melt at a temperature of 50 ° C over the liquidus temperature. For this 1 sheet drawings