EP2949766B1 - Method for producing a valve for an internal combustion engine - Google Patents

Method for producing a valve for an internal combustion engine Download PDF

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Publication number
EP2949766B1
EP2949766B1 EP15167871.1A EP15167871A EP2949766B1 EP 2949766 B1 EP2949766 B1 EP 2949766B1 EP 15167871 A EP15167871 A EP 15167871A EP 2949766 B1 EP2949766 B1 EP 2949766B1
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Prior art keywords
valve
temperature
hardness
internal combustion
cold treatment
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EP15167871.1A
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German (de)
French (fr)
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EP2949766A1 (en
Inventor
Alexander Müller
Matthias Vogelsang
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Mahle International GmbH
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Mahle International GmbH
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
    • B21K1/00—Making machine elements
    • B21K1/20—Making machine elements valve parts
    • B21K1/22—Making machine elements valve parts poppet valves, e.g. for internal-combustion engines
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite

Definitions

  • the present invention relates to a method of manufacturing a valve for an internal combustion engine.
  • the invention also relates to a valve produced by this method and to an internal combustion engine which contains at least one such valve.
  • Valves for internal combustion engines are usually made of high alloyed austenitic steels, such as e.g. made of steels with the material designations X45, X80, X85 and 1.4344.
  • a valve blank made of the steel mentioned subjected to hot forming, so that a raw valve is obtained.
  • the raw valve is then subjected to curing in a vacuum oven and then tempering.
  • the thus heat-treated raw valve is subjected in a conventional manner further processing steps until the finished valve is obtained.
  • valves Due to the heat input into the valve blank during hot forming a structural change is achieved to a harder microstructure, which still contains a large amount of retained austenite. Since valves are to have a uniform microstructure and to be set to a certain hardness value, in the conventional manufacturing method, the above-mentioned steps of curing in a vacuum oven and annealing are performed, whereby the retained austenite content is reduced and the hardness of the valve is adjusted.
  • the present invention addresses the problem of providing a method for manufacturing a valve for an internal combustion engine, which is cheaper than the conventional method and with the reduction of the retained austenite and the adjustment of the hardness of the valve can be easily achieved. Furthermore, to be created with the present invention, a corresponding valve.
  • the present invention is based on the general idea to carry out a method for manufacturing a valve for an internal combustion engine with the steps: hot forming a valve blank to a raw valve, adjusting the structure and the hardness of the raw valve and finishing the raw valve with set structure and set hardness such the setting of the structure and the hardness of the raw valve is carried out by first subjecting the raw valve to a cold treatment at a temperature of ⁇ -100 ° C and then a heat treatment at a temperature of ⁇ 650 ° C.
  • inventive cold treatment at a temperature of ⁇ -100 ° C substantially the same effects as achieved by the conventional hardening treatment in a vacuum furnace are achieved, i.e. in particular the reduction of retained austenite after hot forming.
  • This change in the martensite leads in the heat treatment according to the invention at a temperature of ⁇ 650 ° C for the elimination of a finer distribution of Carbides in the annealed structure, which increases both the toughness and the wear resistance of the valve.
  • the cold treatment is carried out in a conventional manner so that the raw valves are cooled either directly by liquid nitrogen, or by air or alcohol as a refrigerant, which has been cooled by liquid nitrogen. Is cooled to temperatures below -120 ° C, e.g. to -160 ° C, is recommended, initially to an intermediate temperature of e.g. Cool down to -135 ° C, and slowly after a time when the temperature is the same throughout the valve, continue to cool. As a result, cracking in the valve can be avoided.
  • the cooling rate in the cold treatment can be 0.5 to 4 ° C / min, preferably 1 to 3 ° C / min and especially 1 to 2 ° C / min.
  • the cold treatment is carried out for a period of 0.5 to 24 hours, preferably 0.75 to 12 hours, in particular 1 to 6 hours.
  • the heat treatment according to the invention is a per se known tempering treatment according to the invention at a temperature of 650 ° C to 780 ° C, preferably 680 ° C to 750 ° C, especially 690 ° C to 730 ° C, for a period of 1 to 4 hours , preferably 1.5 to 3 hours, in particular 2 to 2.5 hours.
  • the hot forming used in the process according to the invention comprises hot extrusion and forging, as used in a conventional manner for the formation of raw valves from valve blanks.
  • valve blank used in the method according to the invention can be made of known high-alloy steels for valve applications, in particular of a steel with the material designation X45, X80, X85 or 1.4344.
  • Finishing the raw valve with set structure and set hardness includes the usual steps such as e.g. sandblasting immediately after the tempering heat treatment, straightening after sandblasting, and various cutting processes such as sandblasting; Turning and grinding operations.
  • the total costs can thus be reduced by replacing the conventionally performed hardening in the vacuum furnace with the substantially less expensive cooling treatment.
  • the invention provides a valve for an internal combustion engine, which is obtained by the method described above.
  • the valve has a strength of 1000 to 1350 MPa, preferably 1100 to 1350 MPa, in particular 1200 to 1350 MPa, and a Vickers hardness HV1 of 300 to 500, preferably 320 to 480, in particular 340 to 450 on.
  • an internal combustion engine is provided according to the invention, which contains at least one valve, which has been obtained by the method described above.
  • a cylinder liner made of the material X85CrMoV18-2 as valve blank is inductively heated and subjected to hot extrusion at 1150 ° C.
  • the obtained forging blank is swaged directly on the hot extrusion press and the resulting raw valve is cooled in a water-thermisol solution.
  • the raw valve has a martensitic structure with a retained austenite content of> 70%.
  • a cold treatment is then carried out at -100 ° C with a cooling rate of 2 ° C / min and a holding time of 0.5 hours.
  • the martensitic structure of the raw valve after the cold treatment has a retained austenite content of ⁇ 70%.
  • the valve obtained after the cold treatment is then tempered at a temperature of 720 ° C for 2 hours, whereby a hardened valve having a Vickers hardness HV1 of 420 and a strength of 1350 MPa is obtained.
  • An analysis of the structure shows that the retained austenite content has dropped to 0%.
  • the tempered valve is finally subjected to the usual finishing operations, such as sandblasting, straightening, turning and grinding.

Description

Die vorliegende Erfindung betrifft ein Verfahren zum Herstellen eines Ventils für eine Brennkraftmaschine. Die Erfindung betrifft außerdem ein nach diesem Verfahren hergestelltes Ventil sowie eine Brennkraftmaschine, die mindestens ein solches Ventil enthält.The present invention relates to a method of manufacturing a valve for an internal combustion engine. The invention also relates to a valve produced by this method and to an internal combustion engine which contains at least one such valve.

Aus "engine professional" vom 31.12.2011 ist eine cryogenische Behandlung von Maschinenteilen bekannt.From "engine professional" from 31.12.2011 a cryogenic treatment of machine parts is known.

Aus einem Tagungsprotokoll der International Conference in Computational Intelligence (ICCIA) aus dem Jahr 2012 mit dem Titel "Comparison of Effects of Cryogenic Treatment on Different Types of Steels ", ist bekannt, dass mit steigender Wärmebehandlungstemperatur ab einer Temperatur von 600 °C die Gesamthärte und Verschleißbeständigkeit abnimmt.From a Conference Protocol of the International Conference on Computational Intelligence (ICCIA), 2012, entitled "Comparison of Effects of Cryogenic Treatment on Different Types of Steels ", it is known that with increasing heat treatment temperature from a temperature of 600 ° C, the total hardness and wear resistance decreases.

Ventile für Brennkraftmaschinen werden üblicherweise aus hochlegierten austenitischen Stählen, wie z.B. aus Stählen mit den Werkstoffbezeichnungen X45, X80, X85 und 1.4344, hergestellt. Dabei wird bei dem herkömmlichen Herstellungsverfahren zunächst ein Ventilrohling aus den genannten Stählen einem Warmumformen unterzogen, so dass ein Rohventil erhalten wird. Das Rohventil wird anschließend einem Härten in einem Vakuumofen und dann einem Anlassen unterzogen. Anschließend wird das derart wärmebehandelte Rohventil in an sich bekannter Weise weiteren Bearbeitungsschritten unterzogen, bis das fertige Ventil erhalten wird.Valves for internal combustion engines are usually made of high alloyed austenitic steels, such as e.g. made of steels with the material designations X45, X80, X85 and 1.4344. In this case, in the conventional production process, first a valve blank made of the steel mentioned subjected to hot forming, so that a raw valve is obtained. The raw valve is then subjected to curing in a vacuum oven and then tempering. Subsequently, the thus heat-treated raw valve is subjected in a conventional manner further processing steps until the finished valve is obtained.

Durch den Wärmeeintrag in den Ventilrohling während der Warmumformung wird eine Gefügeänderung zu einem härteren Gefüge erreicht, das jedoch noch eine große Menge an Restaustenit enthält. Da Ventile eine gleichmäßige Gefügestruktur aufweisen sollen und auf einen bestimmten Härtewert eingestellt werden sollen, werden in dem herkömmlichen Herstellungsverfahren die vorstehend genannten Schritte des Härtens in einem Vakuumofen und des Anlassens durchgeführt, wodurch der Restaustenitgehalt vermindert wird und die Härte des Ventils eingestellt wird.Due to the heat input into the valve blank during hot forming a structural change is achieved to a harder microstructure, which still contains a large amount of retained austenite. Since valves are to have a uniform microstructure and to be set to a certain hardness value, in the conventional manufacturing method, the above-mentioned steps of curing in a vacuum oven and annealing are performed, whereby the retained austenite content is reduced and the hardness of the valve is adjusted.

Die Härtung in einem Vakuumofen ist jedoch zeitaufwändig und sowohl die Anschaffung als auch der Betrieb eines Vakuumofens sind teuer.However, curing in a vacuum oven is time consuming and both the purchase and operation of a vacuum oven are expensive.

Ferner ist die Durchführung einer Kältebehandlung von legierten Stählen bekannt. Dabei werden insbesondere hochlegierte Werkzeugstähle einer Kältebehandlung unterzogen, um die Standzeit von Werkzeugen, wie z.B. Fräsern, Stanzeinsätzen, Räumwerkzeugen, zu erhöhen.Furthermore, the implementation of a cold treatment of alloyed steels is known. In particular, high-alloy tool steels are subjected to a cold treatment in order to reduce the service life of tools, such as tools. Milling, punching inserts, broaching tools, increase.

Die vorliegende Erfindung beschäftigt sich mit dem Problem, ein Verfahren zum Herstellen eines Ventils für eine Brennkraftmaschine zu schaffen, das kostengünstiger ist als das herkömmliche Verfahren und mit dem die Verminderung des Restaustenits und die Einstellung der Härte des Ventils einfach erreicht werden können. Ferner soll mit der vorliegenden Erfindung ein entsprechendes Ventil geschaffen werden.The present invention addresses the problem of providing a method for manufacturing a valve for an internal combustion engine, which is cheaper than the conventional method and with the reduction of the retained austenite and the adjustment of the hardness of the valve can be easily achieved. Furthermore, to be created with the present invention, a corresponding valve.

Dieses Problem wird erfindungsgemäß durch die Gegenstände der unabhängigen Ansprüche gelöst. Vorteilhafte Ausführungsformen sind Gegenstand der abhängigen Ansprüche.This problem is solved according to the invention by the subject matters of the independent claims. Advantageous embodiments are the subject of the dependent claims.

Die vorliegende Erfindung beruht auf dem allgemeinen Gedanken, ein Verfahren zum Herstellen eines Ventils für eine Brennkraftmaschine mit den Schritten: Warmumformen eines Ventilrohlings zu einem Rohventil, Einstellen des Gefüges und der Härte des Rohventils und Fertigbearbeiten des Rohventils mit eingestelltem Gefüge und eingestellter Härte derart auszuführen, dass das Einstellen des Gefüges und der Härte des Rohventils dadurch erfolgt, dass das Rohventil zunächst einer Kältebehandlung bei einer Temperatur von ≤ -100 °C und dann einer Wärmebehandlung bei einer Temperatur von ≥ 650 °C unterzogen wird.The present invention is based on the general idea to carry out a method for manufacturing a valve for an internal combustion engine with the steps: hot forming a valve blank to a raw valve, adjusting the structure and the hardness of the raw valve and finishing the raw valve with set structure and set hardness such the setting of the structure and the hardness of the raw valve is carried out by first subjecting the raw valve to a cold treatment at a temperature of ≤ -100 ° C and then a heat treatment at a temperature of ≥ 650 ° C.

Durch die erfindungsgemäße Kältebehandlung bei einer Temperatur von ≤ -100 °C werden im Wesentlichen die gleichen Effekte erzielt, wie sie durch die herkömmliche Härtungsbehandlung in einem Vakuumofen erzielt werden, d.h. insbesondere die Verminderung des Restaustenits nach der Warmumformung.By the inventive cold treatment at a temperature of ≤ -100 ° C substantially the same effects as achieved by the conventional hardening treatment in a vacuum furnace are achieved, i.e. in particular the reduction of retained austenite after hot forming.

So wird in dem vorliegenden Verfahren bei einer Durchführung der Kältebehandlung bis zu einer Temperatur von -120 °C die Gefügeumwandlung von Restaustenit zu der festeren und härteren martensitischen Struktur im Wesentlichen vervollständigt, wodurch die Härte des Stahls steigt. Gleichzeitig mit der Härte nimmt auch die Verschleißfestigkeit des Stahls zu.Thus, in the present process, when carrying out the cold treatment to a temperature of -120 ° C, the structural transformation of retained austenite to the firmer and harder martensitic structure is substantially completed, thereby increasing the hardness of the steel. Along with the hardness, the wear resistance of the steel also increases.

Wenn die Kältebehandlung in dem vorliegenden Verfahren bei noch tieferen Temperaturen durchgeführt wird, d.h. bei unterhalb von -120 °C bis -198 °C, wird nicht nur der Restaustenit im Wesentlichen vollständig in Martensit umgewandelt, sondern der Martensit wird ferner kristallographisch und mikrostrukturell verändert. Insbesondere werden feine Martensitnadeln gebildet, wodurch die Härte weiter ansteigt.When the cold treatment in the present process is carried out at even lower temperatures, i. below -120 ° C to -198 ° C, not only is the retained austenite substantially completely converted into martensite, but the martensite is also changed crystallographically and microstructurally. In particular, fine martensite needles are formed, whereby the hardness further increases.

Diese Veränderung des Martensits führt bei der erfindungsgemäßen Wärmebehandlung bei einer Temperatur von ≥ 650 °C auch zur Ausscheidung einer feineren Verteilung von Carbiden in dem angelassenen Gefüge, was sowohl die Zähigkeit als auch die Verschleißfestigkeit des Ventils erhöht.This change in the martensite leads in the heat treatment according to the invention at a temperature of ≥ 650 ° C for the elimination of a finer distribution of Carbides in the annealed structure, which increases both the toughness and the wear resistance of the valve.

Bei einer vorteilhaften Weiterbildung der erfindungsgemäßen Lösung wird deshalb die Kältebehandlung bei einer Temperatur von -100 °C bis -196 °C, insbesondere bei einer Temperatur von -140 °C bis -160 °C, durchgeführt.In an advantageous development of the solution according to the invention, therefore, the cold treatment at a temperature of -100 ° C to -196 ° C, in particular at a temperature of -140 ° C to -160 ° C, performed.

Die Kältebehandlung wird in an sich bekannter Weise so durchgeführt, dass die Rohventile entweder direkt durch flüssigen Stickstoff gekühlt werden, oder durch Luft oder Alkohol als Kälteträger, die bzw. der durch flüssigen Stickstoff gekühlt worden ist. Wird auf Temperaturen unter -120 °C abgekühlt, z.B. auf -160 °C, ist zu empfehlen, zunächst auf eine Zwischentemperatur von z.B. -135 °C abzukühlen, und erst nach einem Zeitpunkt, bei dem die Temperatur innerhalb des gesamten Ventils gleich ist, langsam weiter abzukühlen. Dadurch kann eine Rissbildung in dem Ventil vermieden werden.The cold treatment is carried out in a conventional manner so that the raw valves are cooled either directly by liquid nitrogen, or by air or alcohol as a refrigerant, which has been cooled by liquid nitrogen. Is cooled to temperatures below -120 ° C, e.g. to -160 ° C, is recommended, initially to an intermediate temperature of e.g. Cool down to -135 ° C, and slowly after a time when the temperature is the same throughout the valve, continue to cool. As a result, cracking in the valve can be avoided.

Die Abkühlungsrate bei der Kältebehandlung kann dabei 0,5 bis 4 °C/min, vorzugsweise 1 bis 3 °C/min und insbesondere 1 bis 2 °C/min betragen.The cooling rate in the cold treatment can be 0.5 to 4 ° C / min, preferably 1 to 3 ° C / min and especially 1 to 2 ° C / min.

Bei einer vorteilhaften Weiterbildung der erfindungsgemäßen Lösung wird die Kältebehandlung für einen Zeitraum von 0,5 bis 24 Stunden, vorzugsweise 0,75 bis 12 Stunden, insbesondere 1 bis 6 Stunden durchgeführt.In an advantageous development of the solution according to the invention, the cold treatment is carried out for a period of 0.5 to 24 hours, preferably 0.75 to 12 hours, in particular 1 to 6 hours.

Die erfindungsgemäße Wärmebehandlung ist eine an sich bekannte Anlassbehandlung, die erfindungsgemäß bei einer Temperatur von 650 °C bis 780 °C, vorzugsweise 680 °C bis 750 °C, insbesondere 690 °C bis 730 °C, für einen Zeitraum von 1 bis 4 Stunden, vorzugsweise 1,5 bis 3 Stunden, insbesondere 2 bis 2,5 Stunden durchgeführt wird.The heat treatment according to the invention is a per se known tempering treatment according to the invention at a temperature of 650 ° C to 780 ° C, preferably 680 ° C to 750 ° C, especially 690 ° C to 730 ° C, for a period of 1 to 4 hours , preferably 1.5 to 3 hours, in particular 2 to 2.5 hours.

Das in dem erfindungsgemäßen Verfahren eingesetzte Warmumformen umfasst Warmfließpressen und Schmieden, wie sie in an sich bekannter Weise zur Bildung von Rohventilen aus Ventilrohlingen verwendet werden.The hot forming used in the process according to the invention comprises hot extrusion and forging, as used in a conventional manner for the formation of raw valves from valve blanks.

Der in dem erfindungsgemäßen Verfahren verwendete Ventilrohling kann aus bekannten hochlegierten Stählen für Ventilanwendungen hergestellt sein, insbesondere aus einem Stahl mit der Werkstoffbezeichnung X45, X80, X85 oder 1.4344.The valve blank used in the method according to the invention can be made of known high-alloy steels for valve applications, in particular of a steel with the material designation X45, X80, X85 or 1.4344.

Das Fertigbearbeiten des Rohventils mit eingestelltem Gefüge und eingestellter Härte umfasst die fachüblichen Schritte, wie z.B. ein Sandstrahlen unmittelbar nach der Anlass-Wärmebehandlung, ein Richten nach dem Sandstrahlen und verschiedene spanabhebende Prozesse wie z.B. Dreh- und Schleifvorgänge.Finishing the raw valve with set structure and set hardness includes the usual steps such as e.g. sandblasting immediately after the tempering heat treatment, straightening after sandblasting, and various cutting processes such as sandblasting; Turning and grinding operations.

Bei dem erfindungsgemäßen Verfahren können somit die Gesamtkosten dadurch gesenkt werden, dass das herkömmlich durchgeführte Härten im Vakuumofen durch die wesentlich kostengünstigere Kältebehandlung ersetzt wird.In the method according to the invention, the total costs can thus be reduced by replacing the conventionally performed hardening in the vacuum furnace with the substantially less expensive cooling treatment.

Gemäß einer weiteren Ausführungsform wird erfindungsgemäß ein Ventil für eine Brennkraftmaschine bereitgestellt, das durch das vorstehend beschriebene Verfahren erhalten wird.According to another embodiment, the invention provides a valve for an internal combustion engine, which is obtained by the method described above.

Bei einer vorteilhaften Weiterbildung der erfindungsgemäßen Lösung weist das Ventil eine Festigkeit von 1000 bis 1350 MPa, vorzugsweise 1100 bis 1350 MPa, insbesondere 1200 bis 1350 MPa, und eine Vickers-Härte HV1 von 300 bis 500, vorzugsweise 320 bis 480, insbesondere 340 bis 450 auf.In an advantageous development of the solution according to the invention, the valve has a strength of 1000 to 1350 MPa, preferably 1100 to 1350 MPa, in particular 1200 to 1350 MPa, and a Vickers hardness HV1 of 300 to 500, preferably 320 to 480, in particular 340 to 450 on.

Gemäß einer weiteren Ausführungsform wird erfindungsgemäß eine Brennkraftmaschine bereitgestellt, die mindestens ein Ventil enthält, das mit dem vorstehend beschriebenen Verfahren erhalten worden ist.According to a further embodiment, an internal combustion engine is provided according to the invention, which contains at least one valve, which has been obtained by the method described above.

Weitere wichtige Merkmale und Vorteile der Erfindung ergeben sich aus den Unteransprüchen.Other important features and advantages of the invention will become apparent from the dependent claims.

Es versteht sich, dass die vorstehend genannten Merkmale nicht nur in der jeweils angegebenen Kombination, sondern auch in anderen Kombinationen oder in Alleinstellung verwendbar sind, ohne den Rahmen der vorliegenden Erfindung zu verlassen.It is understood that the above-mentioned features can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Das folgende Beispiel dient lediglich der weiteren Veranschaulichung der Erfindung und ist nicht beschränkend aufzufassen.The following example is merely illustrative of the invention and is not intended to be limiting.

Beispielexample

Ein Zylinderbutzen aus dem Werkstoff X85CrMoV18-2 als Ventilrohling wird induktiv erhitzt und bei 1150 °C einem Warmfließpressen unterzogen. Der erhaltene Schmiederohling wird direkt auf der Warmfließpresse gesenkgeschmiedet, und das erhaltene Rohventil wird in einer Wasser-Thermisol-Lösung abgekühlt. Das Rohventil weist ein martensitisches Gefüge mit einem Restaustenitgehalt von >70 % auf.A cylinder liner made of the material X85CrMoV18-2 as valve blank is inductively heated and subjected to hot extrusion at 1150 ° C. The obtained forging blank is swaged directly on the hot extrusion press and the resulting raw valve is cooled in a water-thermisol solution. The raw valve has a martensitic structure with a retained austenite content of> 70%.

Mit dem erhaltenen Rohventil wird anschließend eine Kältebehandlung bei -100 °C mit einer Abkühlrate von 2 °C/min und einer Haltezeit von 0,5 Stunden durchgeführt. Das martensitische Gefüge des Rohventils nach der Kältebehandlung weist einen Restaustenitgehalt von <70 % auf.With the obtained raw valve, a cold treatment is then carried out at -100 ° C with a cooling rate of 2 ° C / min and a holding time of 0.5 hours. The martensitic structure of the raw valve after the cold treatment has a retained austenite content of <70%.

Das nach der Kältebehandlung erhaltene Ventil wird dann bei einer Temperatur von 720 °C für 2 Stunden angelassen, wobei ein gehärtetes Ventil mit einer Vickers-Härte HV1 von 420 und einer Festigkeit von 1350 MPa erhalten wird. Eine Analyse des Gefüges zeigt, dass der Restaustenitgehalt auf 0 % gesunken ist.The valve obtained after the cold treatment is then tempered at a temperature of 720 ° C for 2 hours, whereby a hardened valve having a Vickers hardness HV1 of 420 and a strength of 1350 MPa is obtained. An analysis of the structure shows that the retained austenite content has dropped to 0%.

Das angelassene Ventil wird schließlich noch den üblichen Fertigbearbeitungsvorgängen unterzogen, beispielsweise einem Sandstrahlen, Richten, Drehen und Schleifen.The tempered valve is finally subjected to the usual finishing operations, such as sandblasting, straightening, turning and grinding.

Claims (7)

  1. Method for producing a valve for an internal combustion engine with the steps:
    hot shaping a valve blank produced from a high-alloyed steel to form a rough valve, adjusting the structure and the hardness of the rough valve and finishing the rough valve with adjusted structure and adjusted hardness characterised in that the structure and hardness of the rough valve are adjusted by the rough value firstly being subjected to a cold treatment at a temperature of ≤ -100°C and then to a heat treatment at a temperature of ≥ 650°C.
  2. Method according to Claim 1, characterised in that the cold treatment is carried out at a temperature of from -100°C to -196°C.
  3. Method according to Claim 2, characterised in that the cold treatment is carried out at a temperature of from -140°C to -160°C.
  4. Method according to any one of Claims 1 to 3, characterised in that the cold treatment is carried out for a period of 0.5 to 24 hours.
  5. Method according to any one of Claims 1 to 4, characterised in that the heat treatment is carried out at a temperature of from 650°C to 780°C.
  6. Method according to any one of Claims 1 to 5, characterised in that the hot shaping comprises hot extrusion and forging.
  7. Method according to any one of Claims 1 to 6, characterised in that the valve blank is produced from a steel with the material designation X45, X80, X85 or 1.4344.
EP15167871.1A 2014-05-21 2015-05-15 Method for producing a valve for an internal combustion engine Active EP2949766B1 (en)

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DE102014209645.6A DE102014209645A1 (en) 2014-05-21 2014-05-21 Method for producing a valve for an internal combustion engine

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EP2949766A1 EP2949766A1 (en) 2015-12-02
EP2949766B1 true EP2949766B1 (en) 2017-03-29

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EP15167871.1A Active EP2949766B1 (en) 2014-05-21 2015-05-15 Method for producing a valve for an internal combustion engine

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EP (1) EP2949766B1 (en)
BR (1) BR102015011623A2 (en)
DE (1) DE102014209645A1 (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2451898A (en) * 2007-08-17 2009-02-18 Federal Mogul Sintered Prod Sintered valve seat

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3136722C2 (en) * 1981-09-16 1986-06-12 TRW Thompson GmbH, 3013 Barsinghausen Process for the production of valves for internal combustion engines
US4741080A (en) * 1987-02-20 1988-05-03 Eaton Corporation Process for providing valve members having varied microstructure
US5534081A (en) * 1993-05-11 1996-07-09 Honda Giken Kogyo Kabushiki Kaisha Fuel injector component
AT507385B1 (en) * 2008-09-30 2011-03-15 Joh Pengg Ag METHOD FOR PRODUCING A COATED STEEL WIRE FOR SPRING ELEMENTS, SPRING STEEL WIRE AND SPRINGS THEREFOR

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2451898A (en) * 2007-08-17 2009-02-18 Federal Mogul Sintered Prod Sintered valve seat

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BR102015011623A2 (en) 2016-04-12
DE102014209645A1 (en) 2015-11-26

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