EP0890652A2 - Wear resisting component made by metal melting - Google Patents

Abstract

In a component, tool or the like made of wear resistant solidified material has a microstructure of metal compound particles (carbide, nitride, carbonitride, boride and/or oxide) in a metallic matrix. At least the wear-exposed region consists of up to 10 (preferably up to 15, especially more than 22) vol.% group IVa and/or Va metal compound(s). Density of the wear exposed region is different to that of the matrix. Also claimed is production of a material for the above component, tool or the like by introducing or forming (by reaction) the above particles in a metal melt and then allowing the melt to solidify. Further claimed is equipment for producing the above component, tool or the like by the above process, in which the casting mould is rotated for subjecting the particles to radial acceleration for disintegration and concentration in the wear-exposed component or tool.

Description

The invention relates to a component, tool body or the like from one wear-resistant, metallurgically manufactured material with a Microstructure consisting of a metallic matrix and embedded in it Grains or particles from at least one metallic compound, namely from Carbide and / or nitride and / or carbonitride and / or boride and / or oxide. Furthermore The invention comprises a method for the production of a metallurgical melt Material for components, tool bodies and parts subject to wear the like, the microstructure of which is embedded and embedded in a metallic matrix Has grains or particles of at least one metallic compound. The The invention also relates to a device for producing components, Tool bodies and the like with high proportions of metallic Connections in a metallic matrix of the material as well as a use the device for the production of rollers.

Metallic connections are connections between at least one metallic and at least one non-metallic element, usually have one great hardness, possibly over 2000 HV and a high melting point, possibly above 3000 ° C and can therefore with increasing proportions in one Matrix improve the wear resistance of the material thus constructed. In terms of sintering, the highest levels of compounds, the so-called Hard materials, adjustable in material. The using such hard powder manufactured sintered body, which is advantageous as a cutting tip as wearing parts highest demands and the like tool components use find, but are limited in their dimensions, require a complex Manufacture and have high material brittleness.

Connections of metallic with non-metallic elements in one Metallic matrix can also be melt metallurgically Elimination from a melt are formed when alloying and / or Cooling and solidification of an alloyed metal melt in this Solubility product of two mutually affine elements one for them characteristic value and so-called primarily excreted Metallic connections are created, which are stored and ultimately in turn improve the wear resistance of the material. On the other hand, are through Heat treatment processes, fine precipitations of connections can be created, which, however, mainly cause an increase in the matrix hardness.

The most important materials with high cutting edge stability and wear resistance represent the ledeburitic steels, especially the high-speed steels. Components or cutting and forming tools made of these steels, in which structure in a metallic matrix with high hardness carbides or Carbide grains to an extent of at least 5% by volume and usually less than 25% by volume have been in use for a long time and form in it State of the art. For example, high-speed steel alloys are used usual compositions mostly produced by melt metallurgy and contain in addition to carbon with concentrations up to approx. 1.5 wt Achieve the desired material properties important carbide-forming metallic elements chrome, molybdenum and / or tungsten as well as vanadium, optionally in small amounts of titanium and / or niobium and in some cases Improvement of matrix toughness cobalt.

When creating the high-speed steel material, the concentration of the respective metallic alloy elements and that of carbon in the To precisely match the melt with regard to their activity and affinity to one another, in order to increase wear resistance as much as possible Carbide content with small carbide grain size in the solidified part or primary material reach and on the other hand with this high carbide content another to ensure sufficient hot formability of the material.

For example, US-3,929,471 is a high-speed steel with a high Wear resistance known, which with a structure made of an iron matrix has stored primary vanadium-niobium mixed carbides. A vanadium-niobium mixed carbide form is chosen because it is this metallic connection with the same density as the melt has.

To further increase the wear resistance of components, in particular of Sendzimir strippers has been proposed in accordance with US 3,929,518 Vanadium and niobium contents of up to 12.0% and up to 10.0% high To provide carbon levels of up to 6.3% in steel in addition to a high Vanadium niobium - mixed carbide content larger amounts of cementite, i.e. iron carbide, in to get the matrix. This can also increase the strength and hardness Matrix metal must be alloyed with the elements common for high-speed steel.

In order to ensure small carbide grain sizes in the matrix metal of a material, has already been suggested (US 4,717,537), a pre-alloy with a high carbide content manufacture and this master alloy of the melt, which is used for the production of the Component is used to add.

From Wo-94/11541 is another way of producing carbide Materials become known, solid carbide particles in a melt introduced and this mixture is allowed to solidify. Preferably, the homogeneous distribution because of the alloyed carbide particles the same density as the melt on and are to improve the wettability in this surface coated.

A production of tool bodies, their central and surface area should have different properties, for example cold rolling according to US 4,484,959 in such a way that on a low alloy Structural steel core a hard layer of high-speed steel, preferably with the Alloy elements carbon, chromium and tungsten or chromium and tungsten, is applied, a powder metallurgical application by welding, in particular with a plasma arc or laser torch.

Furthermore, a composite roller is known from DE-A-4 019 845, which one preferably outer layer created by an electroslag welding process or working position with compressive stresses.

All components, tool bodies or similar plant as well Machine components made of a wear-resistant, melt metallurgical manufactured material with embedded grains or particles from at least A metallic connection has the disadvantages in common that on the one hand in the areas subject to wear the concentration of Hard material particles in the matrix are limited for manufacturing reasons and on the other hand the different mechanical requirement profile for the Component cannot be adequately met. It is also justified by the fact that the density of the To adjust or adapt the connection to the density of the matrix metal in order to consistently set a homogeneous distribution of the connections in the material. For components and tool bodies, this homogeneous structure can be considered with regard to their local demands are often not very effective. For example, a Roller or tube in the areas that are subject to wear have a high concentration of hard material particles in the material, whereas in the segments that absorb the bending or torsional stresses Hard material particles should be kept low.

In order to take the different profile of requirements into account, but also from economic reasons are in special deformation plants Compound rollers used. Such rolls are usually manufactured by means of a centrifugal casting process or a composite casting process.

A high, certain value is due to procedural or manufacturing reasons exceeding concentration of grains or particles of metallic Compounds in molten metals disadvantageous. On the one hand, the pourability is the Melt with increasing proportion of solid particles impaired, whereby Manufacturing problems for the primary material or the components arise, on the other hand can, due to the decreasing solubility product, when cooling down Solidification temperature the primarily excreted metallic compounds or connecting parts continue to grow or crystallize together, resulting in Inhomogeneities or places of particular brittleness in the material leads.

Here the invention seeks to remedy the problem and presents the disadvantages to eliminate the generic state of the art and to improve components, Tool body and the like and an advantageous method with a Specify device for their manufacture.

This object is achieved in that at least in the (the) wear area (s) of the part or body of the material or its structure proportionally at least to 10% by volume, preferably at least 15% by volume, in particular over 22% by volume, by one or more Compound (s) whose metallic part consists of at least one element from the Groups IV A and V A of the periodic table exist, is formed and Compound (s) has a different density compared to the matrix (exhibit).

The advantages achieved by the invention can be seen essentially in the fact that the metallic elements from groups IV A and V A of the periodic table Non-metals can form hard and high-melting compounds, which at Above 10 vol .-% the wear resistance of a material jumped increase. These metals also have a high affinity for carbon, Nitrogen, boron and oxygen, so that their compounds also in a melt or matrix, which has a low concentration of the above non-metallic elements has high resistance. This allows the matrix composition largely independently chosen and the other requirements for the part be adjusted. It is particularly important that the metal component of the Connection from several elements can be formed by alloying and thereby the density of the connections is adjustable. Even the configuration the particle is alloy-based, as was found, about its atomic structure can be influenced, whereby the packing of the particles in the matrix and thus the mechanical properties of the material can be improved.

It is particularly advantageous if the difference in density between the compound (s) and the matrix is at least 21 kg / m ³ , preferably at least 61 kg / m ³ , in particular at least 101 kg / m ³ , because this gives good wear properties in the work zones of the part with high homogeneity are reachable. It is furthermore advantageous if the proportion of grains or particles of the connection (s) is increased in the area of the component's wear.

To ensure good mechanical properties in the case of high wear resistance Reaching the stressed zone of the part or tool can be an advantage if the average diameter of the grains or particles of the compound (s) in the matrix less than 200 microns, preferably less than 50 microns, in particular less than 20 µm.

If the matrix is formed by an iron-based alloy, alloying largely independent of the metallic connections, preferred conditions for thermal tempering of the part created become. This means that even high matrix hardnesses can be achieved, which is the area of application of Parts according to the invention significantly expanded.

If the matrix is made of a nickel base or cobalt base, special ones are Corrosion advantages and high heat resistance values of the material can be achieved.

The procedural object of the invention is achieved in that in a Molten metal Grains or particles of at least one compound whose metallic part from at least one element from groups IV A and V A des Periodic table exists and a different in comparison with the melt Has density, introduced or formed in this by reaction and may be concentrated in sub-areas, with a proportion of at least 10 Vol .-% of at least one compound, whereupon the melt is allowed to solidify. The advantages achieved are essentially due to the fact that fine independent grains introduced or formed and possibly due to the Difference in density in the melt can be distributed unevenly without the high Affinity of these metals for carbon, nitrogen, boron and oxygen because of Example by cooling from high temperatures as a result of falling Solubility of coarse particles, which ultimately affect the mechanical properties of the Can adversely affect material.

It is particularly favorable for the usage properties of the product that if a local concentration of the grains or particles of the metallic Connection (s) in the melt in the areas subject to wear the parts or bodies by the difference in their density or by a Gravity increase is effected.

This creates the possibility of solidifying from a melt Item only high in areas with mainly abrasive loads Hard material shares set, whereas in the remaining object volume one extremely low compound concentrates are given in the matrix and the Transition represents no risk of breakage.

It has proven to be particularly favorable if it is alloy-related the density of the grains or particles with respect to the density of the matrix forming melt is adjusted so that this by the action of Gravity or centrifugal acceleration in those areas of the component or Tool body are concentrated, which ultimately in particular on wear are claimed.

If, as is also advantageously provided, a concentration of the particles or Particles in the melt are caused by centrifugal acceleration high proportions of hard material particles in the matrix can be achieved in a particularly simple manner. Even with small differences in density of the melt and hard material particles due to a technically easy to achieve high centrifugal acceleration a rapid particle movement can be effected. The quickest possible Particle enrichment, if necessary with mutual support of the same, is in the Important with regard to the solidification progress of the residual melt.

It can have high mechanical properties, especially toughness component or tool zones subject to abrasion are improved, if the particles of the metallic compound (s) have a grain diameter or a grain size of at most 200 microns introduced into the melt or are formed, it being advantageous if a proportion of the compound particles in the zone of the body or component that is particularly subject to wear of at least 10% by volume, preferably of at least 15% by volume, in particular of more than 22 vol .-% is set.

A device according to the invention for the production of components, Tool bodies and the like system components is thereby characterized in that the mold (s) can be rotated at such a speed is (are) that the inside or brought into it, if necessary alloyed metal melt containing at least 10% by volume of grains or particles a combination of carbon and / or nitrogen and / or carbon and Nitrogen and / or boron and / or oxygen, with one or more elements from groups IV A and V A of the periodic table in comparison with the Molten metal of different density of such a radial acceleration are subject to a disintegration and consequently a concentration of Connection particles in the intended for high wear Components or tool parts are made.

Such a device makes it possible to remove the particles of the metallic Connection if these are heavier than the matrix melt, outside, or if these are easier to concentrate inside. It can thus advantageously Component or tool body at its local wear be adjusted.

The use of the device according to the invention and is particularly favorable of the method according to the invention for the production of roller bodies with particularly wear-resistant work area. Such rollers with high Hard material concentration in the area of the bale surface can be advantageous for both a deformation of metallic materials, preferably with increased Temperature, as well as for crushing rock such as lava, granite, lime or valuable rock can be used.

Compound rolls, which are advantageous in a rotating device according to the Processes produced according to the invention are not only in their Usage properties significantly improved, but it also exists Outstanding economic usability of tool bodies manufactured in this way.

Furthermore, as has been shown, is a production of a tubular body according to the invention or tube with wear-resistant inner and / or outer surface areas possible by a hard material enrichment, such tubes for transport or can be used cheaply in the case of abrasive sludges.

In the following, the invention is based on only one embodiment illustrative examples explained:

Fig. 1

einen Übergang in einen Bereich mit hoher Konzentration von Verbindungsteilchen

Fig. 2

gerundete Metallkarbidteilchen

Fig. 3

Größere, primär aus einer Schmelze ausgeschiedene und feinere, sekundär durch eine Wärmebehandlung ausgeschiedene Karbide in einer metallischen Matrix

Results of preliminary tests are shown on the basis of micrographs in which the metallic compounds or hard material particles appear light and the metallic matrix dark. Show it:

Fig. 1

a transition to an area with high concentration of compound particles

Fig. 2

rounded metal carbide particles

Fig. 3

Larger carbides in a metallic matrix, which are primarily precipitated from a melt and finer, which are secondary precipitated by heat treatment

Preliminary tests

Approx. 3% by weight of carbon was added to an iron melt that was calmed and kept moving with 20% by weight of niobium. The melt and the niobium carbide compounds formed in it were subjected to an acceleration of 86 times the acceleration of gravity and allowed to solidify.
In a cross section of a test specimen, as shown in FIG. 1, there was a concentration of niobium carbides in the outer region of the test ring with a volume of 39% by volume, whereas the delimited inner region had only low carbide contents.
Because the lattice structure of niobium carbide is formed with sharp edges and preferably oriented in certain directions, the configuration of the grains was changed in the direction of the spherical shape by adding vanadium in the given case, which enables larger packing densities in a matrix . FIG. 2 shows carbide grains produced in this way.
After tempering by means of a heat treatment matched to a hardenable alloy of the matrix, fine, so-called secondary carbides can also be formed in this in addition to the primarily precipitated carbides, as can be seen from FIG. 3 in the area of a transition zone of the particle concentration.

Example 1 :

In a melt in an induction furnace with a composition in% by weight of C = 0.95, Si = 0.50, Mn = 0.80, Al = 0.03, balance iron and accompanying elements became niobium carbide powder by means of a lance using argon blown in, keeping a temperature of 1580 ° C essentially constant has been. The niobium carbide powder particles had an average diameter of 60 µm. After pouring the steel into a pan and inserting it into a centrifugal casting mold, the melt became one Centrifugal acceleration exposed to 60 times the gravitational acceleration and frozen. An examination of the centrifugal casting tube showed that in Area of the outer surface has a niobium carbide concentration of 42% in one Steel matrix, which essentially has the same alloy contents as at the beginning adjusted, was present, with an equal mean carbide grain diameter of 60 microns of the hard pack was given. Towards the inside surface of the Rohres was after the shift with largely the same high particle concentration a steep drop in the carbide content in the matrix is observed, the range of the tubular body on the inner surface had no significant carbide content.

Example 2:

A melt with, in% by weight, 0.02 C, 0.85 Si, 0.35 Mn, 0.80 Cr, 0.96% Ni, 2.1 Mo, 12.2% V was in an induction furnace at a temperature of 1595 ° C by conventional carburizing agents to a total carbon content of 2.85 % Carburized. Cast iron pipes were then manufactured the centrifugal casting process with a centrifugal acceleration of 95 times that Acceleration due to gravity. The cast iron pipes, which after the manufacture of a Subjected to heat treatment had one in the area of the inner surface Concentration of 39% by volume of vanadium carbides in a viscous Matrix, the matrix on the outer surface of the tube being essentially carbide-free Template. The pipes were used for the removal of granulated slag in one Copper smelting plant used, its durability up to the bottom Scrubbing compared to carbide-free pipes was twelve times.

Example 3:

In a melt with a composition of 2.85% C, 0.45% Si, 0.53% Mn, 5.2% Cr, 3.1% Mo, 1.8% W, 4.3% Co, 0.08% Al, balance iron and Accompanying elements were made using a ferroniob wire winding process with a Tantalum content of 12% by weight and ferrovanadium in a ratio of 100 to 6 brought in. With this melt treated in this way took place after the Centrifugal casting the production of the work zone of a compound roller for a sheet production. After processing and heat treatment of the An examination of the intended sample areas was carried out on the roller body, fine niobium-tantalum-vanadium carbides in the near-surface zone of the roller were present in the matrix in a homogeneous distribution. This, in comparison with the matrix heavier, mixed carbides were due to the alloying measure rounded and formed essentially a so-called spherical packing. With such rollers it was possible to increase the performance many times over.

Example 4:

Squeeze plates were sand-cast with slightly exothermic molding material an alloy of the working zone of 3.81% C, 0.40% Si, 0.82% Mn, 14.2% Cr, 0.8% Mo, 18.2% Nb + Ta, 1.4% V, balance iron and accompanying elements Work surface aligned downwards, machined by grinding and thermally tempered. These plates were used in practice at a shredding of lava and limestone as well as one Rock processing in quartz mining. Due to a homogeneous and up to 46 vol .-% and higher-reaching amount of carbide in fine configuration in a hardenable matrix In the area of the work surface, the durability of such crusher components could be increased be significantly increased.

Example 5:

In a Hastelloy N type nickel-based alloy, was introduced Titanium vanadium carbonitrides. This alloy was used for the nuclear industry Centrifugal cast iron pipes manufactured with high internal wear. A Testing the pipes, which have high proportions of a in the area of the inner surface Had Ti-V connection and the determination of the significantly reduced Wear behavior led to an extension of the inspection period 3 times.

Further studies on products with carbides, nitrides, borides and Oxides of the elements from groups IV A and V A of the periodic table showed an advantageous effect of this different density compared to the matrix having and therefore compactible connections to the Wear behavior of components and tool bodies.

Claims (14)

Component, tool body or the like made of a wear-resistant, melt-metallurgically produced material with a microstructure, consisting of a metallic matrix and grains or particles embedded therein, made of at least one metallic compound, namely of carbide and / or nitride and / or carbonitride and / or boride and / or oxide, characterized in that at least in the area (s) of the part or body that is subject to wear, the material or its structure is proportionately at least 10% by volume, preferably at least 15% by volume, in particular more than 22% by volume is formed by one or more compounds, the metallic part of which consists of at least one element from groups IV A and VA of the periodic table, and the compound (s) is different in comparison with the matrix Has density. Component, tool body or the like according to claim 1, characterized in that the density difference between the connection (s) and matrix is at least 21 kg / m ³ , preferably at least 61 kg / m ³ , in particular at least 101 kg / m ³ . Component, tool body or the like according to claim 1 or 2, characterized in that the average diameter of the grains or particles of the compound (s) in the matrix is less than 200 µm, preferably less than 50 µm, in particular less than 20 µm. Component, tool body or the like according to one of claims 1 to 3, characterized in that the matrix is formed by an iron-based alloy. Component, tool body or the like according to one of claims 1 to 3, characterized in that the matrix is formed by a nickel-based or cobalt-based alloy. Process for the melt-metallurgical production of a material for components, tool bodies or the like subject to wear, the microstructure of which comprises a metallic matrix and grains or particles of at least one metallic compound embedded therein, namely of carbide and / or nitride and / or carbonitride and / or boride and / or oxide, characterized in that grains or particles of at least one compound, the metallic part of which consists of at least one element from groups IV A and VA of the periodic table and which has a different density compared to the melt, are introduced or into a metal melt are formed in this by reaction and optionally concentrated in partial areas, whereupon the melt is solidified with at least 10% by volume of at least one compound. A method according to claim 6, characterized in that a concentration of the grains or particles of the metallic compound (s) in the melt in the areas of the parts or bodies subject to wear is caused by the difference in their density or by an increase in gravity. Method according to one of claims 6 or 7, characterized in that, in terms of alloy technology, the density of the grains or particles is adjusted with regard to the density of the melt forming the matrix in such a way that it is affected by the effect of gravity or acceleration in those areas of the component or Tool body are concentrated, which are ultimately particularly stressed for wear. Process according to Claims 6 to 8, characterized in that the particles or particles are concentrated in the melt by centrifugal acceleration. Method according to one of claims 6 to 9, characterized in that the particles of the metallic compound (s) with a grain diameter or a grain size of at most 200 µm are introduced into the melt Method according to one of Claims 6 to 10, characterized in that a proportion of the connecting particles in the zone of the body or component which is particularly subject to wear is at least 10% by volume, preferably at least 15% by volume, in particular more than 22% Vol .-% is set. Device for producing components, tool bodies and similar system components with a high proportion of metallic compounds in a matrix, in particular according to claims 1 to 5 and for carrying out the method according to claims 6 to 11, characterized in that the mold (s) with a such a speed is (are) rotatable that the metal melt contained therein or incorporated therein, optionally alloyed, containing at least 10% by volume of grains or particles of a compound of carbon and / or nitrogen and / or carbon and nitrogen and / or boron and / or oxygen, with one or more elements from groups IV A and VA of the periodic table with such a radial acceleration that can be exposed in comparison with the molten metal to such a degree that a disintegration and consequently a concentration of connecting particles in the Ba intended for high wear stress u or tool parts. Use of a device according to claim 12 and in particular one Process according to claims 6 to 11 for the production of rolls. especially of composite rollers with a particularly wear-resistant working area for shaping metallic materials at room temperature and preferably elevated temperature. Use of a device according to claim 12 and in particular one Process according to claims 6 to 11 for the production of a tubular body or a tube with wear-resistant inner and / or outer Surface area.

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