EP0869857A1 - Process for manufacturing hard metal parts - Google Patents

Process for manufacturing hard metal parts

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Publication number
EP0869857A1
EP0869857A1 EP96942363A EP96942363A EP0869857A1 EP 0869857 A1 EP0869857 A1 EP 0869857A1 EP 96942363 A EP96942363 A EP 96942363A EP 96942363 A EP96942363 A EP 96942363A EP 0869857 A1 EP0869857 A1 EP 0869857A1
Authority
EP
European Patent Office
Prior art keywords
hard metal
binder
thermoplastic binder
viscosity
hard
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP96942363A
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German (de)
French (fr)
Other versions
EP0869857B1 (en
Inventor
Reinhard Lenk
Claus Richter
Waldemar Hermel
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Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
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Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/05—Mixtures of metal powder with non-metallic powder
    • C22C1/051—Making hard metals based on borides, carbides, nitrides, oxides or silicides; Preparation of the powder mixture used as the starting material therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/22—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip
    • B22F3/225—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip by injection molding

Definitions

  • the invention relates to the fields of ceramics and the hard metal industry and relates to a method for producing hard metal components, in particular with complicated geometries, as e.g. are used as processing tools and wear elements.
  • Ceramic or powder-metallurgical components of complex geometry can be manufactured by carrying out mechanical post-processing of the outer contours based on raw molded parts. In the case of such materials, it is possible to carry out the post-processing in the shaped, sintered or state given between these process steps. The processing effort increases with the hardness of the material in the respective state, with the complexity of the geometry and with the number of pieces.
  • the injection molding of powder metal and ceramic is known, which is based on the fact that an non-plastic powder is mixed with a thermoplastic plastic binder and an injection molding compound which is flowable at higher temperatures is produced and can be processed on conventional plastic injection molding machines (US 2122960, DE 680250).
  • thermoplastic molding process which is based on the liquefaction of non-plastic ceramic powders by paraffins and waxes.
  • the shape of thermoplastic suspensions is already low
  • DD 286 311 Also known from DD 286 311 is a process for the production of molded parts from sintered materials by injection molding, in which a plasticized mass is prepared from a pretreated metal powder and an organic binder, which after the binder has been driven out is processed into molded parts by subsequent injection molding and then sintered becomes.
  • the binder consists of paraffin and polyethylene wax.
  • thermoplastic binder 3 to 6 mPa s
  • high density differences between the hard metal powder and the binder used (12 to 24 times) no stable dispersed thermoplastic Suspensions can be made.
  • the production of such stable-dispersion thermoplastic suspensions is the prerequisite for the production of green bodies with reproducible homogeneity and density and thus for a production implementation that is ready for series production.
  • Tungsten carbide components of complex geometries, even in large numbers, have so far been produced essentially by cost-intensive mechanical post-processing in the sintered state.
  • the object of the invention is to provide a method for producing hard metal components in which hard metal components with complex geometries can be produced using a stable, disperse hard metal binder suspension with a thermoplastic binder having a viscosity of 3 to 6 mPa s and without using an organic one Debinding solvent.
  • a hard metal powder with an average grain size ⁇ 2.0 ⁇ m is liquefied with a thermoplastic binder mixed, wherein the viscosity of the mixture during the entire production and processing is set to a value of at least 100 mPa s and up to ⁇ 4000 mPa s, and the stabilized dispersion obtained in this way is processed into a shaped body, from which the thermoplastic binder is then driven out and the debindered molding is then sintered.
  • Paraffins, waxes and surface-active additives are advantageously used as thermoplastic binders.
  • hard materials are WC, TaC, NbC, VC TiC M02C, Co, Ni or mixtures of these hard materials in powder form.
  • Hard material powders with an average grain size of 0.5 to 1.5 ⁇ m are also advantageously used.
  • the viscosity of the mixture of hard metal powder and liquefied thermoplastic binder is set to a value of 100 to 2000 mPa s during the entire production and processing.
  • the hard metal powder is added to the liquid thermoplastic binder in several stages.
  • the method according to the invention makes it possible to produce a stable, disperse hard-material-thermoplastic binder suspension which can then be processed into a shaped body by means of hot molding (low-pressure injection molding).
  • a hard material powder mixture consisting of 16.6% by mass of Co, 87.8% by mass of WC and 1.6% by mass of TaC, NbC, VC, with an average grain size of 0.9 ⁇ m
  • a thermoplastic binder consisting of 25 g paraffin and 5 g stearic acid, processed as follows to form a slip (suspension).
  • the binder constituents paraffin and stearic acid are melted in a heated stirred vessel at 80 ° C. and 300 g of the hard metal powder are added. This mixture is stirred intensively.
  • the slip produced in this way is conveyed from a storage container to which a pressure of 0.6 MPa has been applied, via a pipeline system into a closed shape with the negative component shape with a complex geometry.
  • the mold is opened, the component is debindered by slowly increasing the temperature under inert gas up to 300 ° C and then sintered at 1450 ° C.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Powder Metallurgy (AREA)

Abstract

The invention relates to the field of the ceramic and hard metal industries and concerns a process for manufacturing hard metal parts, in particular those having a complex geometry, such as those used for example as machining tools and wear elements. The object of the invention is to create a process which allows the manufacture of hard metal parts with a complex geometry by using a stable dispersed hard metal-binder suspension, in which the binder is a thermoplastic binder having a viscosity of 3 to 6 mPas, and without using an organic solvent to eliminate the binder. For that purpose, a process is disclosed wherein a hard metal powder having an average corn size smaller than 2.0 νm is mixed with a liquefied thermoplastic binder, the viscosity of the mixture being set upon a value of at least 100 mPas and up to 4000 mPas during the whole production and treatment process. The thus obtained stable disperse suspension is shaped into a moulded body from which the thermoplastic binder is then expelled and the binder-free shaped body is then sintered.

Description

Verfahren zur Herstellung von HartmetallbauteilenProcess for the production of hard metal components
Technisches GebietTechnical field
Die Erfindung bezieht sich auf die Gebiete der Keramik und der Hartmetallindustrie und betrifft ein Verfahren zur Herstellung von Hartmetallbauteilen, insbesondere mit komplizierten Geometrien, wie sie z.B. als Bearbeitungswerkzeuge und Verschleißelemente zur Anwendung kommen.The invention relates to the fields of ceramics and the hard metal industry and relates to a method for producing hard metal components, in particular with complicated geometries, as e.g. are used as processing tools and wear elements.
Stand der TechnikState of the art
Keramische oder pulvermetallurgische Bauteile komplizierter Geometrie können gefertigt werden, indem man von Rohformkörpern ausgehend eine mechanische Nachbearbeitung der äußeren Konturen durchführt. Bei derartigen Werkstoffen ist es möglich, die Nachbearbeitung im geformten, gesinterten oder einem zwischen diesen Verfahrensschritten gegebenen Zustand durchzuführen. Dabei erhöht sich der Bearbeitungsaufwand mit der Härte des Werkstoffes im jeweiligen Zustand, mit der Komplexität der Geometrie und mit der Stückzahl.Ceramic or powder-metallurgical components of complex geometry can be manufactured by carrying out mechanical post-processing of the outer contours based on raw molded parts. In the case of such materials, it is possible to carry out the post-processing in the shaped, sintered or state given between these process steps. The processing effort increases with the hardness of the material in the respective state, with the complexity of the geometry and with the number of pieces.
Große Stückzahlen pulvertechnologischer oder keramischer Werkstoffe werden kostengünstig durch endformnahe ("near net shape") thermoplastische Formgebungsverfahren gefertigt.Large quantities of powder technology or ceramic materials are inexpensively manufactured using near-net shape thermoplastic molding processes.
Bekannt ist das Spritzgießen von Pulvermetall und Keramik, das darauf beruht, daß ein unplastisches Pulver mit einem thermoplastischen Kunststoffbinder vermischt wird und eine bei höheren Temperaturen unter Druck fließfähige Spritzgußmasse entsteht, die auf herkömmlichen Kunststoffspritzgießmaschinen verarbeitet werden kann (US 2122960, DE 680250).The injection molding of powder metal and ceramic is known, which is based on the fact that an non-plastic powder is mixed with a thermoplastic plastic binder and an injection molding compound which is flowable at higher temperatures is produced and can be processed on conventional plastic injection molding machines (US 2122960, DE 680250).
Bekannt ist ebenfalls ein thermoplastisches Formgebungsverfahren, welches auf dem Verflüssigen unplastischer keramischer Pulver durch Paraffine und Wachse beruht. Die Formgebung thermoplastischer Suspensionen ist bereits bei geringenAlso known is a thermoplastic molding process which is based on the liquefaction of non-plastic ceramic powders by paraffins and waxes. The shape of thermoplastic suspensions is already low
ORIGINAL UNTERLAGEN Drücken möglich (SU 137807). Das Verfahren wird Heißgießen oder Niederdruckspritzgießen genannt. Unterschiedliche keramische Werkstoffe (Aluminiumoxid, Zirkonoxid, Siliciumcarbid) wurden mit diesem Verfahren bereits verarbeitet. Die werkstoffspezifischen Besonderheiten liegen vor allem im Versatz des thermoplastischen Binders, der in jedem Fall grenzflächenaktive Stoffe für die Modifizierung der Pulveroberfläche beinhaltet (SU 298566, SU 298567, DD 139397, DD 233117, DD 233119, SU 1590468). Maschinenkonzepte für die Realisierung des Formgebungsverfahrens sind bekannt (US 4416603, DD 281913). Eine Übersicht über das Heißgießverfahren ist ebenfalls veröffentlicht (Lenk, R. Technische Keramische Werkstoffe, Kapitel 3.4.8.1).ORIGINAL DOCUMENTS Pressing possible (SU 137807). The process is called hot molding or low pressure injection molding. Different ceramic materials (aluminum oxide, zirconium oxide, silicon carbide) have already been processed with this process. The material-specific peculiarities lie primarily in the offset of the thermoplastic binder, which in any case contains surface-active substances for modifying the powder surface (SU 298566, SU 298567, DD 139397, DD 233117, DD 233119, SU 1590468). Machine concepts for realizing the shaping process are known (US 4416603, DD 281913). An overview of the hot casting process is also published (Lenk, R. Technical Ceramic Materials, Chapter 3.4.8.1).
Bekannt ist weiterhin aus der DD 286 311 ein Verfahren zum Herstellen von Formteilen aus Sinterwerkstoffen durch Spritzgießen, bei dem aus einem vorbehandelten Metallpulver und einem organischen Bindemittel eine plastifizierte Masse aufbereitet wird, die nach dem Austreiben des Bindemittels durch anschließendes Sprizgießen zu Formteilen verarbeitet und danach gesintert wird. Das Bindemittel besteht dabei aus Paraffin und Polyethylenwachs.Also known from DD 286 311 is a process for the production of molded parts from sintered materials by injection molding, in which a plasticized mass is prepared from a pretreated metal powder and an organic binder, which after the binder has been driven out is processed into molded parts by subsequent injection molding and then sintered becomes. The binder consists of paraffin and polyethylene wax.
Weiterhin ist nach Dropmann, u.a., Metall, 45. Jg. Heft 5, Mai 1991 der pulvermetallurgische Spritzguß von Hochleistungswerkstoffen bekannt. Die verwendeten Bindemittel bestimmen dabei im wesentlichen, ob ein Spritzgießen der Masse und eine vollständige Formfüllung möglich wird. Dabei kommt der Viskosität der Massen eine besondere Bedeutung zu. Spritzgußmassen mit einer Viskosität von < 4000 mPa s sind dabei nicht anwendbar.Furthermore, according to Dropmann, et al., Metall, 45th vol. Issue 5, May 1991, powder metallurgical injection molding of high-performance materials is known. The binders used essentially determine whether injection molding of the mass and complete mold filling is possible. The viscosity of the masses is of particular importance. Injection molding compounds with a viscosity of <4000 mPa s cannot be used.
Bislang ist es nicht möglich, Hartmetallwerkstoffe mit dem Heißgießverfahren zu verarbeiten, da aufgrund der niedrigen Viskosität des thermoplastischen Binders (3 bis 6 mPa s) und der hohen Dichteunterschiede zwischen dem Hartmetallpulver und dem verwendeten Binder (12- bis 24-fach) keine stabildispersen thermoplastischen Suspensionen hergestellt werden können. Die Herstellung derartiger stabildisperser thermoplastischer Suspensionen ist aber die Voraussetzung für die Fertigung von Grünkörpern mit reproduzierbarer Homogenität und Dichte und damit für eine serienfähige industrielle Umsetzung. Hartmetallbauteile komplexer Geometrien auch in größerer Stückzahl werden bislang im wesentlichen durch eine kostenintensive mechanische Nachbearbeitung im gesinterten Zustand hergestellt.So far, it has not been possible to process hard metal materials with the hot casting process, because due to the low viscosity of the thermoplastic binder (3 to 6 mPa s) and the high density differences between the hard metal powder and the binder used (12 to 24 times) no stable dispersed thermoplastic Suspensions can be made. However, the production of such stable-dispersion thermoplastic suspensions is the prerequisite for the production of green bodies with reproducible homogeneity and density and thus for a production implementation that is ready for series production. Tungsten carbide components of complex geometries, even in large numbers, have so far been produced essentially by cost-intensive mechanical post-processing in the sintered state.
In den letzten Jahren ist eine Spritzgußtechnologie entwickelt worden, die die Möglichkeiten einer Großserienfertigung mit dem Vorteil der Darstellung sehr komplexer Geometrien verbindet (DE 3808123.7). Um die Probleme bei diesem Verfahren, die sich aus dem hohen Dichteunterschied zwischen dem Pulver und dem Binder, sowie den sehr hohen Fließgeschwindigkeiten beim Formfüllprozeß ergeben (Entmischung und Separation), zu minimieren, werden höherviskose Kunststoffbinder verwendet. Diese temporären Kunststoffbinder werden in einem geschlossenen Entbinderungsprozeß durch Extraktion mit Hilfe organischer Lösungsmittel ausgetrieben, bevor die Bauteile gesintert werden (Graf, W. u.a., Pulvermetall in Wissenschaft und Praxis, Band 7, VDI-Verlag, Düsseldorf, 1991, S. 275 - 285).In recent years, an injection molding technology has been developed that combines the possibilities of large series production with the advantage of displaying very complex geometries (DE 3808123.7). In order to minimize the problems with this process, which result from the high density difference between the powder and the binder, and the very high flow rates in the mold filling process (separation and separation), higher-viscosity plastic binders are used. These temporary plastic binders are driven out in a closed debinding process by extraction with the aid of organic solvents before the components are sintered (Graf, W. et al., Pulvermetall in Wissenschaft und Praxis, Volume 7, VDI-Verlag, Düsseldorf, 1991, pp. 275-285 ).
Die Grenzen dieses Verfahrens liegen in einer komplizierten Prozeßführung, hohen Werkzeugkosten, die sich erst bei sehr großen Stückzahlen amortisieren, und der aus Aspekten des Umweltschutzes schwierig zu handhabenden Verwendung großer Mengen organischer Lösungsmittel.The limits of this process lie in a complicated process control, high tool costs, which only pay for themselves in very large quantities, and the use of large amounts of organic solvents, which are difficult to handle from environmental aspects.
Darstellung der ErfindungPresentation of the invention
Die Aufgabe der Erfindung besteht darin, ein Verfahren zur Herstellung von Hartmetallbauteilen anzugeben, bei dem Hartmetallbauteile mit komplexen Geometrien hergestellt werden können unter Verwendung einer stabildispersen Hartmetall-Binder-Suspension mit einem thermoplastischen Binder einer Viskosität von 3 bis 6 mPa s und ohne Einsatz eines organischen Lösungsmittel zur Entbinderung.The object of the invention is to provide a method for producing hard metal components in which hard metal components with complex geometries can be produced using a stable, disperse hard metal binder suspension with a thermoplastic binder having a viscosity of 3 to 6 mPa s and without using an organic one Debinding solvent.
Die Aufgabe wird durch die in den Ansprüchen angegebene Erfindung gelöst.The object is achieved by the invention specified in the claims.
Bei dem erfindungsgemäßen Verfahren zur Herstellung von Hartmetallbauteilen wird ein Hartmetallpulver einer mittleren Korngröße < 2,0 μm mit einem verflüssigten thermoplastischen Binder gemischt, wobei die Viskosität der Mischung während der gesamten Herstellung und Verarbeitung auf einen Wert von mindestens 100 mPa s und bis < 4000 mPa s eingestellt wird, und die so erhaltene stabildisperse Suspension zu einem Formkörper verarbeitet wird, aus dem anschließend das thermoplastische Bindemittel ausgetrieben und der entbinderte Formkörper dann gesintert wird.In the method according to the invention for producing hard metal components, a hard metal powder with an average grain size <2.0 μm is liquefied with a thermoplastic binder mixed, wherein the viscosity of the mixture during the entire production and processing is set to a value of at least 100 mPa s and up to <4000 mPa s, and the stabilized dispersion obtained in this way is processed into a shaped body, from which the thermoplastic binder is then driven out and the debindered molding is then sintered.
Vorteilhafterweise werden als thermoplastischer Binder Paraffine, Wachse und grenzflächenaktive Zusätze eingesetzt.Paraffins, waxes and surface-active additives are advantageously used as thermoplastic binders.
Weiterhin vorteilhafterweise werden als Hartstoffe WC, TaC, NbC, VC TiC M02C, Co, Ni oder Mischungen dieser Hartstoffe in Pulverform eingesetzt.Also advantageously used as hard materials are WC, TaC, NbC, VC TiC M02C, Co, Ni or mixtures of these hard materials in powder form.
Ebenfalls vorteilhafterweise werden Hartstoffpulver einer mittleren Korngröße von 0,5 bis 1 ,5 μm eingesetzt.Hard material powders with an average grain size of 0.5 to 1.5 μm are also advantageously used.
Es ist auch vorteilhaft, daß die Viskosität der Mischung aus Hartmetallpulver und verflüssigtem thermoplastischen Binder während der gesamten Herstellung und Verarbeitung auf einen Wert von 100 bis 2000 mPa s eingestellt wird.It is also advantageous that the viscosity of the mixture of hard metal powder and liquefied thermoplastic binder is set to a value of 100 to 2000 mPa s during the entire production and processing.
Es ist weiterhin vorteilhaft, daß das Hartmetallpulver in mehreren Stufen dem flüssigen thermoplastischen Binder zugegeben wird.It is also advantageous that the hard metal powder is added to the liquid thermoplastic binder in several stages.
Durch das erfindungsgemäße Verfahren wird es möglich, eine stabildisperse Hartstoff- thermoplastische Binder-Suspension herzustellen, die dann mittels Heißgießen (Niederdruckspritzgießen) zu einem Formkörper verarbeitet werden kann.The method according to the invention makes it possible to produce a stable, disperse hard-material-thermoplastic binder suspension which can then be processed into a shaped body by means of hot molding (low-pressure injection molding).
Damit werden aufwendige Nachbearbeitungen von Hartmetallbauteilen in jedem Zustand der Herstellung vermieden und es ist weder ein solch hoher technologischer Aufwand notwendig, wie ihn der Einsatz von höherviskosen Binder erfordert, noch müssen große Mengen an organischen Lösungsmitteln für die Entbinderung eingesetzt werden. Mit Hilfe des erfindungsgemäßen Verfahrens werden auch trotz der auftretenden großen Dichteunterschiede zwischen den Hartstoffpulvern und dem Binder stabildisperse Suspensionen erreichbar. Die Primärteilchen in der Suspension werden stabilisiert und eine Sedimentation und damit der Verlust der Homogenität der Mischung wird vermieden.This avoids costly reworking of hard metal components in every state of manufacture and it does not require the high technological effort required by the use of higher-viscosity binders, nor do large amounts of organic solvents have to be used for debinding. With the aid of the method according to the invention, in spite of the large differences in density between the hard material powders and the binder, it is possible to obtain stable disperse suspensions. The primary particles in the suspension are stabilized and sedimentation and thus the loss of homogeneity of the mixture are avoided.
Bester Weg zur Ausführung der ErfindungBest way to carry out the invention
Im weiteren wird die Erfindung an einem Ausführungsbeispiel erläutert.The invention is explained below using an exemplary embodiment.
Beispielexample
500 g eines Hartstoffpulvergemisches, bestehend aus 16,6 Ma.-% Co, 87,8 Ma.-% WC und 1 ,6 Ma.-% TaC, NbC, VC, mit einer mittleren Korngröße von 0,9 μm werden mit einem thermoplastischen Binder, bestehend aus 25 g Paraffin und 5 g Stearinsäure, folgendermaßen zu einem Schlicker (Suspension) verarbeitet. Die Binderbestandteile Paraffin und Stearinsäure werden in einem beheizten Rührgefäß bei 80 °C aufgeschmolzen und 300 g des Hartmetallpulvers wird dazugegeben. Diese Mischung wird intensiv gerührt. Da sich während des Rührens die Viskosität der Mischung deutlich verringert, werden vor Unterschreiten einer Viskosität von 100 mPa s weitere 100 g des Hartstoffpulvergemisches zu der Mischung gegeben. Dadurch wird die Viskosität der Mischung sofort erhöht und die Sedimentationsstabilität des Schiickers ist weiterhin gegeben. Nach weiterem intensiven Rühren werden die restlichen 100 g Hartstoffpulver zugegeben und weiterhin gerührt.500 g of a hard material powder mixture consisting of 16.6% by mass of Co, 87.8% by mass of WC and 1.6% by mass of TaC, NbC, VC, with an average grain size of 0.9 μm, are mixed with a thermoplastic binder, consisting of 25 g paraffin and 5 g stearic acid, processed as follows to form a slip (suspension). The binder constituents paraffin and stearic acid are melted in a heated stirred vessel at 80 ° C. and 300 g of the hard metal powder are added. This mixture is stirred intensively. Since the viscosity of the mixture decreases significantly during stirring, a further 100 g of the hard material powder mixture are added to the mixture before the viscosity falls below 100 mPa s. As a result, the viscosity of the mixture is immediately increased and the sedimentation stability of the feeder remains intact. After further intensive stirring, the remaining 100 g of hard material powder are added and stirring is continued.
Der so hergestellte Schlicker wird aus einem Vorratsbehälter, der mit einem Druck von 0,6 MPa beaufschlagt ist, über ein Rohrleitungssystem in eine geschlossene Form mit der Negativbauteilform mit einer komplexen Geometrie gefördert. Nach dem Erkalten des Schlickers wird die Form geöffnet, das Bauteil durch langsame Temperaturerhöhung unter Inertgas bis 300 °C entbindert und anschließend bei 1450 °C gesintert. The slip produced in this way is conveyed from a storage container to which a pressure of 0.6 MPa has been applied, via a pipeline system into a closed shape with the negative component shape with a complex geometry. After the slip has cooled, the mold is opened, the component is debindered by slowly increasing the temperature under inert gas up to 300 ° C and then sintered at 1450 ° C.

Claims

Patentansprüche claims
1. Verfahren zur Herstellung von Hartmetallbauteilen, bei dem ein Hartmetallpulver einer mittleren Korngröße < 2,0 μm mit einem verflüssigten thermoplastischen Binder gemischt wird, wobei die Viskosität der Mischung während der gesamten Herstellung und Verarbeitung auf einen Wert von mindestens 100 mPa s und bis < 4000 mPa s eingestellt wird, und die so erhaltene stabildisperse Suspension zu einem Formkörper verarbeitet wird, aus dem anschließend das thermoplastische Bindemittel ausgetrieben und der entbinderte Formkörper dann gesintert wird.1. A process for the production of hard metal components, in which a hard metal powder with an average grain size <2.0 μm is mixed with a liquefied thermoplastic binder, the viscosity of the mixture during the entire production and processing to a value of at least 100 mPa s and up to < 4000 mPa s is set, and the stabilized dispersion obtained in this way is processed into a shaped body, from which the thermoplastic binder is then expelled and the debindered shaped body is then sintered.
2. Verfahren nach Anspruch 1 , bei dem als thermoplastischer Binder Paraffine, Wachse und grenzflächenaktive Zusätze eingesetzt werden.2. The method according to claim 1, in which paraffins, waxes and surface-active additives are used as the thermoplastic binder.
3. Verfahren nach Anspruch 1 , bei dem als Hartstoffe WC, TaC, NbC, VC, TiC, M02C, Co, Ni oder Mischungen dieser Hartstoffe in Pulverform eingesetzt werden.3. The method according to claim 1, in which the hard materials used are WC, TaC, NbC, VC, TiC, M02C, Co, Ni or mixtures of these hard materials in powder form.
4. Verfahren nach Anspruch 1 , bei dem Hartstoff pulver einer mittleren Korngröße von 0,5 bis 1 ,5 μm eingesetzt werden.4. The method of claim 1, are used in the hard material powder an average grain size of 0.5 to 1.5 microns.
5. Verfahren nach Anspruch 1 , bei dem die Viskosität der Mischung aus Hartmetallpulver und verflüssigtem thermoplastischen Binder während der Herstellung und Verarbeitung auf einen Wert von 100 bis 2000 mPa s eingestellt wird.5. The method of claim 1, wherein the viscosity of the mixture of hard metal powder and liquefied thermoplastic binder is adjusted to a value of 100 to 2000 mPa s during manufacture and processing.
6. Verfahren nach Anspruch 1 , bei dem das Hartmetallpulver in mehreren Stufen dem flüssigen thermoplastischen Binder zugegeben wird. 6. The method of claim 1, wherein the hard metal powder is added to the liquid thermoplastic binder in several stages.
EP96942363A 1995-12-15 1996-12-05 Process for manufacturing hard metal parts Expired - Lifetime EP0869857B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19546901 1995-12-15
DE19546901A DE19546901C1 (en) 1995-12-15 1995-12-15 Production of hard metal components
PCT/EP1996/005452 WO1997022427A1 (en) 1995-12-15 1996-12-05 Process for manufacturing hard metal parts

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EP0869857A1 true EP0869857A1 (en) 1998-10-14
EP0869857B1 EP0869857B1 (en) 2001-03-07

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DE (2) DE19546901C1 (en)
WO (1) WO1997022427A1 (en)

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EP0869857B1 (en) 2001-03-07
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WO1997022427A1 (en) 1997-06-26
US5972286A (en) 1999-10-26

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