EP2984287A2

EP2984287A2 - Annular tool

Info

Publication number: EP2984287A2
Application number: EP14723967.7A
Authority: EP
Inventors: Bernhard Feistritzer
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-04-12
Filing date: 2014-04-09
Publication date: 2016-02-17
Also published as: DE202014101693U1; WO2014165887A3; AT514133B1; WO2014165887A2; AT514133A1; CN105339587A; US20160298451A1

Abstract

The invention relates to an annular tool (1) having at least one working region (4) oriented radially outward and having high wear resistance, and a clamping part (5) closer to the axis, in particular a roller bit or cutting ring for rock, in particular for tunnel boring machines, made of a material which is formed from an iron-based alloy as matrix having incorporated hard material particles, wherein the hard material particles are formed from carbide and/or nitride and/or oxide and/or boride, possibly as carbonitride or oxycarbonitride having a boron component of at least one of the elements, or in mixed form of the elements from groups 4 and 5 of the periodic system, and have a density at room temperature of more than 7400 kg/m³, preferably of more than 7600 kg/m³. The invention further relates to methods for the production thereof.

Description

RINGTONED TOOL

The invention relates to an annular Tool with at least one radially outward working area with high wear resistance and an achsnäheren clamping part, in particular a Roller chisel or cutting ring for rock, in particular for Tunnel boring machines.
Furthermore, the invention relates to a Method for producing annular tools with at least one radially outward working area and an achsnäheren 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, optionally in a mixed form of the elements of the groups 4 and / or 5 of the periodic table are stored.

State of the art
Drilling rigs for rock formations or rock and The like, are mostly for larger diameter with annular tools equipped, which have an outward working area and Roll under pressure on the rock bottom and thereby a removal or a Break out of this effect.
For example, tunnel boring machines have a large size dish-shaped tool holder in which a variety of so-called Roller bits or cutting rings are mounted rotatably mounted. When driving The tool holder is rotated and pressed with high force to the mountains, the same arranged on different radii of the roller bit in the respective areas of rock are effectively breaking and the eroded Rock or the so-called cuttings discharged behind the tool holder becomes.
The mechanical requirements should be annular tool with a tapered, radially outward facing Work area, in this particular a high wear resistance as well have high hardness and high toughness of the material.
In most cases, the tool raw part is on an axis Shrunk, whereby tensile stresses inevitably arise in the clamping area, which in the heavy, the hard rock breaking operation, each one for it required compressive stresses of the material are superimposed and no in the Substantially stationary loads of the tool material result.
Roller bits should therefore have a workspace highest possible wear resistance and a clamping range with sufficient high toughness and high toughness and overall a superior Break resistance of the material with changing mechanical stress, because a failure of a tool costly repairs with a Standstill of the drill caused.
The cutting rings usually consist of a Tool steel. The shaping is generally done via a Forging process, the desired material properties by a subsequent heat treatment can be achieved. The person skilled in the art is aware that a maximum wear resistance of tool steels only with a high Hardness of the structure is achievable. Here must be accepted that with increasing hardness decreases the toughness of the structure. To achieve the for Tool steels best properties in terms of hard use as Cutting ring, must be a compromise between highest wear resistance and high tenacity.
Various attempts have been made by Combination of extremely wear-resistant materials with solid but tough Materials to extend the life of the cutting rings. DE 10 2005 039 036 B3 describes, for example, a steel roller chisel, which in the work area having welded segments, said carbide particles of Contain tungsten carbide. From JP 2000001733 A is a similar cutting ring known, which has a on the outer periphery of a base body of ductile iron has applied carbide ring. Furthermore, from the writings JP 2007138437 A, GB 1188305, GB 1379151, DE10300624A1 and DE 101 61 825 A1 Cutting rings for tunnel boring machines known, which arranged on the outer circumference Segments, or cylindrical or otherwise specially shaped parts Have carbide, which by soldering, pressing or pouring with the Basic body to be connected. Also in CA 2 512 737 A1 a cutting ring described in which segments of hard metal between two discs axially be clamped. All of these known approaches involve either a very elaborate and difficult production or perform for example high thermal stresses when using or by softening the solder to early failure of the cutting rings in use. In JP 59144568 A is a Manufacturing process for cutting rings described in which a melt, which contains tungsten carbide-based cemented carbide particles, into a rotating one Mold is poured, whereupon the hard metal particles in the outdoor area focus on the cast body. This method has the disadvantage that the the melt added hard metal particles partially through the melt be dissolved and in the solidification unwanted, brittle structural components can form in the structure of the tool. Also, the minimum size is the added carbide particles limited by the dissolution process.
Object of the invention
The invention sets itself the goal of a generic, annular tool to create, which in the hard, rock breaking operation allows an increased service life.
Furthermore, it is the object of the invention to provide a Method of the type mentioned for the production of annular Specify tools that correspond to the respective stresses a have optimal material structure.
The above aim is a generic, To create a ring-shaped tool, which in the hard, rock-breaking operation An increased service life is achieved by the tool off a material consisting of an iron-based matrix alloy with is formed in this embedded hard material particles. The hard material particles can be made of carbide, nitride, oxide or boride, but also as compounds this, such as carbonitride, carboboride or oxicarbonitride with Boron, be formed. Depending on the application, it may be advantageous that mixtures of these different types of hard materials in the tool are included. The metal content in the hard material particles comes essentially from Groups 4 and 5 of the Periodic Table (Ti, Zr, Hf, V, Nb, Ta), wherein also here only single elements from these groups or mixtures of these in may be contained in the hard materials. Compared to the many in the Eisenmetallurgie used hard materials whose metallic components from the Group 6 of the Periodic Table (e.g., tungsten carbide) have hard materials from metals of groups 4 and 5 the advantage that these in practice common 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 materials used during the Solidification of an iron base melt and during the further cooling of the be formed or eliminated from this resulting workpiece, preferably Form eutectic microstructures or segregate at grain boundaries. The thus formed hard materials, the toughness of the structure can be clearly reduce. The advantage of the low solubility of the above hard materials in one Iron meltdown lies in the fact that on the one hand large amounts of this Hard materials may be contained as solid particles in the melt, wherein on the other hand, in the solidification of the melt and in the further cooling of the Workpiece only small amounts of additional hard particles in the structure be formed or excreted. These small amounts of brittle Hard materials affect the toughness of the structure only to a small extent negative. These can increase the toughness but even if the excreted particles are sufficiently fine to grain growth of the matrix during a heat treatment decrease.
To be highly resistant to wear and long To achieve the service life of the roller chisel, both a minimum share of Hard material ponds are present in the structure, as well as the hard material particles in such a way be distributed inhomogenously in the cutting ring, that a high proportion of these in the located radially outward working area of the roller bit. For considered as sufficient volume fraction of the wear-resistant Working range of about 8 volume% (vol%), has a hard material content of at least 5 vol .-%, in each case based on the entire workpiece, as suitable proved. At least 8% by volume of hard particles are necessary if heavy Working conditions are provided for the cutting ring. The possible Operating time of the roller chisel can with larger volume portion of the Work area are increased. So the percentage of the work area can be up about 25% by volume and above are increased to long use times at the same time to enable difficult conditions of use.
The desired distribution of the hard material ponds in the Cutting ring is achieved if its density is higher than the density of the melt is and they move outward in the centrifugal casting process. tries have shown that good results are already achieved when the density of the Hard material particles at room temperature is greater than 7400kg / m³. A desired, high concentration of hard material ponds in the work area is achieved when at room temperature a density greater than 7600 kg / m³ exhibit. Hard materials with this density are, for example, carbides, nitrides and Carbonitrides of niobium, which have been proven in experiments. It has too shown that a slight addition of vanadium to these niobium hardstocks the However, growth and the properties of the particles can have a favorable influence with the addition of vanadium the density of the particles decreases. A ratio of Nb Atomic% / V atomic%> 5 should be used for niobium-vanadium mixed carbides optionally carbonitrides may be, at least be respected. Higher concentrations of these particles in the work area are combined with a Ratio Nb atomic% / V atomic%> 10 achieved.
The person skilled in the art is aware that the Wear resistance of a structure not only on the hardness of the matrix and the embedded hard material particles, as well as their ratio depends, but also depends on the size distribution of the hard material particles. in the In the following, all structural constituents are understood as a matrix which does not correspond to the above-mentioned hard material particles are. If the hard particles are too small, so These can be in the furious wear as whole particles from the matrix be removed without increasing the wear resistance especially. Are the However, if particles are too large, these can be under the high pressure load during of the rock breaking mission break and thereby also the Do not increase wear resistance sufficiently. In the present case the Roller Chisel has been shown to give the best results if at least 60% by volume, preferably at least 75% by volume of the hard material particles are formed with a size of less than 70μm.
Besides the properties of the hard material particles are Also, the properties of the matrix of crucial importance to a high To achieve wear resistance in the working area of the roller chisel. In particular, the properties of the matrix are crucial to a sufficient toughness of the structure both in the work area, as well as in the Clamping range, to allow. The properties of the matrix will be above all by their chemical composition and by a possible heat treatment founded. Carbon is the most important alloying element and influences before In particular, the hardenability of the steel, with about 0.28% C as the lower limit for a sufficient hardenability of the steel is considered for the present application becomes. At a carbon content of over 1.2% in the matrix, a Carbide network form in the structure, which reduces its toughness. Silicon increases the strength and the wear resistance but also the Castability of the melt, but should not exceed 2% in the matrix. Manganese sets the critical cooling rate for the formation of martensite and, with a sufficient amount of up to 2%, allows the air to be hardened Cutting rings. By higher manganese contents up to 25%, the solubility of Carbon in austenite can be significantly increased and the conversion properties austenite may be affected by cooling or mechanical stress. With manganese contents up to 25%, the carbon content in the matrix can also reach up to 2.3%. Like manganese, chromium also increases the hardenability of steel and forms secondary and tertiary carbides, which are excreted from the austenite and increase the wear resistance, too high chromium contents too lead a chromium carbide network in the structure. The chromium content should therefore not higher than 6.0%. Nickel also favors like manganese and chromium the martensite formation and additionally increases the toughness of the matrix. For nickel a content of 2.5% appears as the upper limit in the matrix to reach the necessary properties as sufficient. To set a low Critical cooling rate has a combination of Mn, Cr and Ni reinforced. Molybdenum increases the strength of the matrix up to about 2.2% increases the wear resistance through the formation of carbides. Tungsten forms together with Nb and V mixed carbides as well as mixed nitrides and can thus increase the density increase these hard substances. However, the content of W in the melt is so to adjust that after the ejection of the primary formed hard materials in the matrix only has a content of max. 1.5% is included, otherwise together with Mo can form a network of W-Mo mixed carbides. For this Reason should also be 1.5xMo + W not more than 3.5%. Due to the high affinity of Nb and V to C and N remain of these in the matrix only small amounts from below max. 0.8% back.
Like Nb and V, Ti, Zr, Hf and Ta remain as well only small amounts in the matrix. Cobalt can increase the heat resistance for cutting rings which are subject to particularly high loads up to a content of 3% in be included in the matrix. For deoxidation, the melt is often Al added, which is still partially dissolved in the matrix after solidification can stay. Higher levels of Al can increase the density of the melt reduced and thus increases the density difference to the hard particles become. An Al content of up to 3% in the matrix is possible.
As a base composition for the matrix are suitable especially the alloys of alloyed tool steels, as specified in the standard DIN 10020 are described. It can both cold work steel, hot work steel and high speed steels used as the base composition for the matrix become. To avoid eutectic carbides, it is in the High speed steels partly necessary, the carbon content compared to the Standard composition to reduce. With these matrix alloys can by a suitable heat treatment, which generally consists of a hardening process and a start-up process, the trouble-free use of the Cutting rings required hardness of at least 44HRC can be achieved. It has demonstrated that a particularly good wear resistance is achieved when the Matrix of the cutting rings has a hardness of 50HRC and above. This hardness is needed when in hard, especially weary rock formations is bored. The heat treatment of the cutting rings is always on the special Application to adapt the application to a balance between To achieve hardness and toughness of the structure.
Is the matrix composition according to a Manganese steel, so the advantage of a particularly tough and can impact-resistant basic structure together with a pressure-hardening and thus wear-resistant surface can be used. In 'Houdremont, Handbook of the Special steel customer, Springer publishing house, 1956 'and other Literaturen become Such manganese hard steels, which also invented Hadfield steels called austenitic manganese tool steels according to their structure, described. These steels have a manganese content of about 8% by weight to 15% % By weight, exceptionally 6 to 25% by weight, and a carbon content of about 0.8 to 2.3 wt .-%. The ratio of wt.% Mn to wt.% C is included about 10: 1. Manganese hard steels are characterized by a corresponding Heat treatment characterized by making their structure of a metastable, very tough Austenite exists. By compressive stress of the surface, the metastable Turning austenite into a hard and wear-resistant martensite, which makes you obtains a hard surface and tough core component. Depending on the proportion of Mn and C in the steel and their quantitative ratio to each other, can Conversion behavior can be influenced.
To form the hard, martensitic surface alone the load during the use can be sufficient. Is that enough Pressure load during use is not sufficient to get the needed conversion of the To cause structure in the surface, so can be cured Surface area for example by hammering or another mechanical Treatment should be cured before use. The composition of Matrix alloy can also be adjusted so that the surface or the entire tool body by cooling below room temperature, preferably by means of liquid nitrogen, at least partly in martensite can be converted.
It can be described above chisel or similar annular tools, which at least one radially outward directed work area and an axis closer clamping part included, and off 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 in Mixed form of the elements of groups 4 and / or 5 of the periodic table embedded are to be manufactured, in which in a first step one Base alloy, for example, in an induction furnace, melted and on a Temperature is heated from 1350 ° C to 1630 ° C. This base melt serves most alloying elements for the later finished alloy in the To introduce melt.
The base melt can vary depending on the desired Matrix composition and depending on the choice of execution of the following second step, the following composition in wt .-%:
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 (Al) to 3.5
possibly
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 rest.
If the metallic constituents of the hard material particles to be formed later are already contained in the base melt (elements from groups 4 and 5) and at the same time the proportion of C, N and B is kept as low as possible, in a second step carbon and / or nitrogen and Boron or introduced into the base melt, whereupon these elements with the already in the base melt elements of Group 4 and / or 5 of the Periodic Table to Hardstoffteilchen, which have a higher density than the melt connect. The hard materials formed have the structure M x (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 components, or the ratio x: y is between 1.5 and 0.8. The amount of alloyed carbon is to be selected such that a carbon content of 0.3 to 2.3 wt% C 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 hard materials at the same time low wear of the melting vessel results when the temperature of the Base melt is maintained between 1550 ° C and 1630 ° C. The Zulegieren of Carbon, nitrogen and boron can be absorbed by solids 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 Carbon, nitrogen and boron content of the added component or Components, very large quantities of these may be necessary to the desired carbon, nitrogen and boron content in the finished melt to reach. The amount of added carbon, nitrogen and boron carriers can thus be significantly larger than the amount of base melt, which the alloying element proportions in the base melt assume very high contents can, e.g. Niobium up to 35% by weight.
The melting of one of the elements of the 4th and / or main group rich alloy with low levels of carbon, Nitrogen and boron has the advantage that the ferroalloys, over which In general, the elements of the 4th and 5th group are alloyed quickly dissolve. At too high levels of carbon, nitrogen and boron in the Melt can build up on the surface of the ferroalloys used form a hard material layer, which greatly hinders the resolution. It has in experiments showed that the proportion of carbon in the base melt in the above case should be less than 0.6 wt .-%.
It is also possible in the first step the Adjust composition of the base melt so that these elements does not contain to the formation of the hard material particles 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 of metal and Hard material particles, added and homogeneously distributed in the base melt. These hard particles may be carbides and / or nitrides and / or oxycarbonitrides and / or borides, optionally as carbonitrides and / or oxicarbonitrides with Borane parts, at least one of the elements or in mixed form of the elements of Groups 4 and 5 of the periodic table. The homogeneous distribution of Hard material particles in the base melt can by mechanical methods, for Example by stirring, or by the injection of gases in the bottom Supported area of the melting vessel.
Depending on the composition of the composition and the composition the formed or introduced hard material particles 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 reduced ambient pressure perform.
After the homogeneous distribution of the hard material particles in the second step, the matrix melt with the contained therein Hard material particles are poured in a third step into a rotating mold and allowed to freeze. Caused by the rotational movement around the Longitudinal axis of the mold and thereby on the melt and the Centrifugal force acting on hard particles, the hard particles migrate outside in the later work area of the roller chisel, where they have an Hard materials form very rich microstructure. At the same time forms in the Indoors a microstructure, which only small contents at the primary has excreted or introduced hard materials. The resulting Proportion of hard materials in the outdoor area is mainly due to the Process parameters rotational speed of the mold, the density difference between the Hard material particles and the melt, the size distribution of the hard material particles and the cooling rate of the melt in the rotating mold certainly. For a high concentration of hard particles in the outdoor area and In order to achieve high wear resistance, the speed should be the Mold and thus acting on the melt and on the hard particles Centrifugal acceleration should be as high as possible. Centrifugal accelerations from 700 m / s² and above, measured on the outside diameter of the casting, have become proven. A high density difference between the hard material particles and the Melting can be done mainly by high levels of niobium, tantalum and hafnium in the hard materials are achieved. For cost reasons, have particularly Niobium-rich hard materials, in particular niobium-vanadium mixed carbides, for Achieving a high proportion of hard material proved favorable. The second In any case, step precipitated or added hard material particles should have a density greater than that of the matrix melt in a Temperature 50 ° C above its liquidus temperature.
The migration of the hard particles to the outside requires depending on the dimension of the casting different time and Achieving a maximum possible concentration of hard materials in the outer structure should be the time between the pouring of the melt into the mold and the solidification of the melt should be as large as possible. Preheat the mold on Several 100 ° C can bring slight advantages here. The strong Solidification rate be reduced when the mold as a whole or in parts facing the casting from a material exists, which conducts the heat only very bad. Here are above all Quartz sand and molded materials based on aluminum silicate ceramics. Also a ceramic or ceramic based heat insulating coating Carbon base on the inside of the mold brings advantages here.
After the casting of the blank, this can, to the To keep stresses in the ring low, with a temperature of up to 1000 ° C be removed from the mold, in an oven, the temperature over the balanced ring and then cooled so slowly that the Matrix structure is in a soft state at room temperature. The Cooling speed depends here on the alloy composition the matrix. If it is the later conditions of use of the roller chisel require, e.g. drilling in particularly hard rock, so after the Emptying the blank from the mold of this in an oven to the appropriate Forging be brought and this then in drop forging be plastically deformed in one or more stages. Through this process the toughness of the structure can be increased significantly. To the forging process then close the controlled cooling to room temperature. After that you can the blank mechanically by e.g. Turning to be preprocessed, whereupon a Heat treatment of the ring follows. This can, in the case of a Matrix composition similar to a tool steel, from a hardening process and at least one starting process exist. For a matrix composition Similar to a manganese-hard steel is generally carried out after an annealing treatment a rapid cooling to reach a metastable, austenitic structure. After the heat treatment follows the mechanical finishing of the Cutting ring by e.g. Turning and / or grinding.
Subsequently, the invention is based on a described example.
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 in an induction oven melted, brought to a temperature of 1590 ° C, at this temperature for Held for 5 minutes and then at constant temperature with petroleum coke on brought a carbon content of 2.35%. After carburizing, the Temperature of the finished melt lowered to 1570 ° C, held there for 3 minutes and then poured in a centrifugal casting process. As a centrifugal casting mold a steel mold was used, into which a core of bound Silica was inserted. This core was previously used on the inside surface 1mm thick zirconia-based sizing coated. The casting was added about 800 ° C taken from the mold and after a balancing phase of 60min in Stove in this cooled to room temperature, then preprocessed and through Hardening and tempering twice to a hardness of 53 HRC in the clamping range brought.
FIG. 1 shows an example of a cutaway annular roller chisel 1 with the cross-section 2. The with hard particles Enriched 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 of hard materials.
FIG. 2 shows by way of example the microstructure in FIG Work area 4, where the hard particles bright and the matrix dark are shown. The hard material content is about 20%.
FIG. 3 shows, for comparison, the microstructure in FIG Clamping range 5 with only a small amount of hard materials.

Claims

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 bit or cutting ring for rock, in particular for tunnel boring machines, characterized in that the tool of a material consisting 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 boride, optionally as carbonitride or oxycarbonitride with boron content of at least one of the elements, or in a mixed form of 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 have a higher volume in the work area (4).

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 about 20 to 25%, of the tool (1), in which working range more than 60 vol .-%, preferably more than 75 vol .-%, the hard material particles are formed with a size of less than 70 microns.

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.

Nb [At .-%] / V [At .-%]> 5, preferably> 10

5. Tool (1) according to one of the preceding claims, characterized in that the matrix alloy has a chemical composition in 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

Chrome (Cr) to 6.0

Nickel (Ni) to 2.5

Molybdenum (Mo) to 2.2

Tungsten (W) to 1.5

(1,5xMo + W) up to 3,5

Vanadium (V) to 0.8

Niobium (Nb) to 0.4

Cobalt to 3.0

Aluminum (Al) up to 3.0

Possibly

Titanium (Ti) to 0.2

Zircon (Zr) to 0.2

Hafnium (Hf) to 0.1

Tantalum (Ta) to 0.25

Iron (Fe) and impurity elements as rest

having.

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. Method for producing annular tools (1) with at least one radially outwardly directed working area (4) and a near-axis clamping part (5), in particular roller bits or cutting rings for Rock, in particular for tunnel boring machines, formed from a Iron-based alloy as a matrix, in which hard material particles, such as carbides and / or nitrides and / or carbonitrides and / or borides, optionally in Mixed form of the elements of groups 4 and / or 5 of the periodic table embedded are, if necessary for the production of a tool according to at least one of preceding claims, wherein 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, an addition or a formation in or in the melt the base alloy of hard particles with a higher density, whereupon, in a third step, the matrix melt with the hard material particles in a mold for the annular tool a rotational movement about the Longitudinal axis is subjected and allowed to solidify.

9. The method according to claim 8, wherein in the first step Base alloy with 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

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 (Al) to 3.5

possibly

Titanium (Ti) to 2.0

Zircon (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 rest

is melted.

10. The method according to any one of claims 8 or 9, wherein in second step, the hard material particles, such as carbides and / or nitrides and / or Oxicarbonitrides and / or borides, optionally as carbonitrides and / or Oxicarbonitrides with borane parts, at least one of the elements or in Mixed form of the elements of Groups 4 and 5 of the Periodic Table by means of a solid or liquid, metallic pre-melt or by means of a like Mixture of metal and hard particles with a diameter of Hard material particles smaller than 70 μm in the liquid base alloy be distributed and distributed homogeneously in the third step under rotation in the mold a solidification of the mixture Hard material particles and a matrix alloy formed from the base alloy and the metal portion of the pre-melt takes place.

11. The method according to any one of claims 8 or 9, wherein the Base alloy having a carbon content of below 0.6 wt .-% C melted and is heated to a temperature of 1550 ° C to 1630 ° C, after which in a second step, an addition of the alloying elements carbon and / or Nitrogen and / or boron, optionally as a master alloy, takes place and these Elements with the group 4 and / or group 5 solved elements 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 a sum of carbon, nitrogen and Boron from 0.4 to 0.55 atomic parts and a higher density than the melt and that from 0.3 to 2.3% by weight of carbon remains in the liquid metal, whereupon, in a third step, the melt in a mold for the annular tool subjected to a rotational movement about the longitudinal axis and is frozen, and in further steps, a processing and a Heat treatment of the tool done.

12. The method according to claim 11, wherein the elements of Groups 4 and 5 of the periodic table in their respective concentration in the Base alloy can be chosen that the density of the primary excreted Hard material particles is greater than that of the melt at a temperature of 50 ° C. above the liquidus temperature.