WO2010020212A1 - Method for mould annealing with intermediate cooling - Google Patents
Method for mould annealing with intermediate cooling Download PDFInfo
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- WO2010020212A1 WO2010020212A1 PCT/DE2009/001108 DE2009001108W WO2010020212A1 WO 2010020212 A1 WO2010020212 A1 WO 2010020212A1 DE 2009001108 W DE2009001108 W DE 2009001108W WO 2010020212 A1 WO2010020212 A1 WO 2010020212A1
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- board
- cooling
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- intermediate cooling
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Classifications
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- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/62—Quenching devices
- C21D1/673—Quenching devices for die quenching
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
- B21D22/02—Stamping using rigid devices or tools
- B21D22/022—Stamping using rigid devices or tools by heating the blank or stamping associated with heat treatment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J1/00—Preparing metal stock or similar ancillary operations prior, during or post forging, e.g. heating or cooling
- B21J1/06—Heating or cooling methods or arrangements specially adapted for performing forging or pressing operations
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
- B21J5/02—Die forging; Trimming by making use of special dies ; Punching during forging
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- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
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- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/62—Quenching devices
- C21D1/667—Quenching devices for spray quenching
Definitions
- the present invention relates to a method for
- a usually boron-alloyed steel is austenitized at about 900 ° C to 950 ° C and introduced directly from the oven as quickly as possible in a forming tool and formed at a high operating speed.
- a usually hydraulic presses and special cooled tools are used, with which sufficient for the martensite cooling rate can be realized.
- the cooling of the workpiece determines the final hardness and
- the sheets are first cold preformed, then heated and cured in a cooled mold. This makes it possible to realize more complex transformations than direct form hardening.
- DE 10 2005 003 551 A1 discloses a hot-forming process in which the end product is intended to be a formed sheet-metal part with an interstage structure. This is achieved by a method which is applicable to curable thin sheets, preferably for steel sheets with a C content of about 0.1% to about 0.3%. The method is characterized in that following a austenitizing heating of the steel sheet to above the A C3 point is followed by a comparatively rapid cooling to a temperature range of 400 ° C to 600 ° C. Upon reaching this temperature range, an isothermal deformation of the sheet into its final shape.
- Characteristic of this method is that before the transformation neither the bainite, nor the ferrite, nor the pearlite, nor the martensite is achieved, and that the transformation is made isothermal until the interstage area is reached and adjusts a sacred processngeglage.
- the invention is based on the object, starting from the prior art to develop a mold hardening process, which represents a significant reduction in the process cycle time and which has as a final product a formed sheet with defined or preselected strength values.
- Another object of the invention is the targeted influence on the flow behavior of the material to prevent wrinkles and ripples in the formed workpiece.
- the invention is based on the idea to introduce a further process step between the heating and the associated austenitizing of the blanks or preformed workpieces and the cooling in the forming tool in order to significantly shorten the time for workpiece cooling in the forming tool compared to known methods.
- the boards or preformed workpieces are cooled after the heating before the complete cooling takes place in a forming tool.
- Characteristic of the hot forming process according to the invention is that both the intermediate cooling, as well as the cooling of the formed workpiece in the forming tool are controlled in time so that the end product is a formed sheet with a defined mixed structure or a purely martensitic structure. Both coolings have to be precisely defined in terms of time, so that the desired microstructural transformations arise.
- the invention provides for two types of intermediate cooling, by contact and by convection.
- the blanks are guided past cooling elements in the passage, which can be designed, for example, as cooling rollers and / or plate-shaped.
- the shape of the cooling elements and the pressure forces of the boards to the cooling elements determine the Intensity of cooling.
- the invention includes methods and systems with which the boards are cooled uniformly and those in which a partially different cooling takes place.
- the inventive method also includes the ability to perform the intermediate cooling under a protective gas atmosphere to prevent scaling.
- the workpieces are cooled by blowing with air, special gases, spray or sprayed with liquids. Processes and plants are possible in which the workpieces are cooled in a continuous process and those in which the cooling takes place at a standstill. As with contact cooling, it is also conceivable for convection cooling that the workpieces or sinkers are cooled both uniformly and partially differently.
- the inventive method also includes the use and processing of joined boards or boards with partially different thicknesses.
- Figure 1 shows a first embodiment of the method according to the invention for mold hardening with an intermediate cooling by convection.
- a circuit board 1 is lifted from a blank stack 2 and fed into a furnace 3.
- the transport of the board 1 in the furnace 3 and also in the following
- the furnace 3 can be carried out, for example, as a roller hearth furnace.
- the board 1 In order to achieve austenitization, the board 1 must be heated to a sufficient temperature when passing through the furnace 3. Subsequently, the circuit board 1 is not inserted as in the conventional direct form hardening in a coolable forming tool, but it goes through a Intercooling station 4.
- the intermediate cooling station 4 consists of one or more cooling stages 5, in which air or special gases are blown through one or more openings on the board 1 and thus achieve a cooling effect.
- These openings can have different shapes. They can for example be performed as holes, but also all other geometric shapes are conceivable. Also, 5 nozzles can be installed in the cooling stages to improve the cooling effect. Even linear openings are conceivable, but these often have unfavorable flow conditions.
- the forming press 6 is usually a hydraulic press, because the plunger 7 must remain with the upper tool 8 at the lower reversal point for several seconds. In addition to hydraulic presses, this requirement can also be met by servo presses or toggle presses and are thus also suitable for this form hardening method.
- the plunger 7 moves down with the upper tool 8 and forms the board 4 to its final contour.
- the tool 8, 10 initially remains in the closed state. During this time, the deformed board 4 is cooled as long and so fast until the desired structure is established in the formed workpiece.
- the shape of the workpiece remains stable and it will be achieved very good accuracies on the formed workpiece.
- the cooling in the tool 8, 10 is usually carried out by means of the lower tool 10 and the upper tool 8 located cooling channels.
- the duration of the cooling in closed mold 8, 10 is significantly reduced in the inventive mold hardening process compared to the conventional mold hardening process, because due to the cooling in the intermediate cooling station, the heat energy which has to be dissipated in the cooling tool 8, 10 is significantly reduced.
- Figure 2 shows a second embodiment of the method according to the invention for mold hardening with an intermediate cooling by contact.
- This second embodiment differs from the first embodiment by the type of intercooling.
- the intermediate cooling station 4 in Figure 2 is a contact cooling.
- the board 1 is cooled by contact with cooling rollers 11.
- the cooling rollers 11 are arranged in pairs in this example. The pairs of cooling rollers 11 clamp the circuit board 1. At least one of
- Cooling roller pairs is driven, so that the board 1 is conveyed through the intermediate cooling station 4.
- the contact pressure and the shape of the cooling rollers affect the cooling capacity.
- As a cooling medium for heat removal from the cooling rollers 11 in principle all common cooling media in question.
- FIG 3 Figure 4 and Figure 5 different variants for the arrangement of the cooling rollers 11 are shown.
- the board 1 is pressed by two smaller cooling rollers 13 against a cooling roller 12 with a large diameter.
- the advantage of this arrangement is that the board 1, the cooling roller 12 over a large wrap angle touched. As a result, this arrangement guarantees a good cooling performance.
- FIG. 4 shows a cooling roller arrangement which corresponds to that in FIG.
- the cooling rollers 11 are arranged in pairs and exert a pressing force on the board 1 from both sides. As a result, high contact pressures are possible, which guarantee good cooling performance.
- FIG. 5 shows a further possibility for arranging the cooling rollers.
- the opposing cooling rollers 14 are arranged offset to one another. This results in larger contact surfaces between the board and cooling rollers, which has an advantageous effect on the cooling capacity.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
Description
"Verfahren zum Formhärten mit Zwischenkühlung" "Method of Form Hardening with Intercooling"
Beschreibungdescription
Die vorliegende Erfindung betrifft ein Verfahren zurThe present invention relates to a method for
Warmumformung, bei dem ein härtbares Stahlblech nach einer austenitisierenden Erwärmung und vor einer Abkühlung in einem Werkzeug eine Zwischenkühlung erfährt.Hot forming in which a hardenable steel sheet undergoes intercooling after austenitizing heating and before cooling in a tool.
Stand der TechnikState of the art
Bauteile aus hochfesten Blechen werden zunehmend im Automobilbau verwendet. Sie erhöhen die Festigkeit, verbessern das Crashverhalten und reduzieren das Fahrzeuggewicht deutlich. Das so genannte Formhärten oder auch Presshärten dieser hochfesten Blechwerkstoffe ermöglicht den Bau leichterer und dennoch extrem steifer Karosseriebauteile durch die Kombination von Wärmebehandlung und Formgebung mit gleichzeitiger kontrollierter Abkühlung. Bei dem Verfahren des Formhärtens wird nicht nur ein deutlicher Festigkeitszuwachs des Materials nutzbar, darüber hinaus ist auch die Verformbarkeit bei hoher Temperatur über des 20-fache höher als die Verformbarkeit von Stahlblechen mit vergleichbarer Endfestigkeit, die kalt verformt werden. Daher ist bei diesem Verfahren oftmals der Verformungsprozess in einem Schritt möglich, während bei kalter Verformung mehrere Pressenhübe erforderlich sind. Beira Formhärten unterscheidet man prinzipiell zwei Verfahren, das direkte und das indirekte Verfahren. Beim direktem Formhärten wird ein in der Regel borlegierter Stahl bei ca. 900° C bis 950° C austenitisiert und direkt aus dem Ofen möglichst schnell in ein Umformwerkzeug eingebracht und mit hoher Arbeitsgeschwindigkeit umgeformt. Zum Umformen werden üblicherweise hydraulische Pressen und spezielle gekühlte Werkzeuge eingesetzt, mit denen eine für die Martensitbildung ausreichende Abkühlgeschwindigkeit realisiert werden kann. Das Abkühlen des Werkstückes bestimmt die endgültige Härte undComponents made of high-strength sheets are increasingly being used in the automotive industry. They increase the strength, improve the crash behavior and reduce the vehicle weight significantly. The so-called form hardening or press hardening of these high-strength sheet metal materials allows the construction of lighter yet extremely rigid body components by combining heat treatment and shaping with simultaneous controlled cooling. In the method of mold-hardening not only a significant increase in the strength of the material is available, moreover, the deformability at high temperature is more than 20 times higher than the deformability of steel sheets with comparable final strength, which are cold-formed. Therefore, in this method, often the deformation process in one step is possible, while cold deformation requires several press strokes. In principle, Beira tempering is divided into two processes, direct and indirect. In direct mold hardening a usually boron-alloyed steel is austenitized at about 900 ° C to 950 ° C and introduced directly from the oven as quickly as possible in a forming tool and formed at a high operating speed. For forming usually hydraulic presses and special cooled tools are used, with which sufficient for the martensite cooling rate can be realized. The cooling of the workpiece determines the final hardness and
Festigkeit. Das nach der Umformung und Kühlung harte Werkstück wird dann hart beschnitten und weiterbearbeitet.Strength. The hard workpiece after forming and cooling is then trimmed hard and processed further.
Beim indirekten Formhärten werden die Bleche zunächst kalt vorgeformt, danach erwärmt und in einer gekühlten Form gehärtet. Damit lassen sich komplexere Umformungen realisieren als beim direkten Formhärten.In indirect mold hardening, the sheets are first cold preformed, then heated and cured in a cooled mold. This makes it possible to realize more complex transformations than direct form hardening.
In der DE 24 52 486 Al wird ein direktes Formhärteverfahren zur Herstellung eines gehärteten Blechprofils aus einer Platine beschrieben. Danach wird ein aus härtbarem Stahl bestehendes Blechprofil auf eine Härtetemperatur erhitzt. Anschließend wird es mittels einer Warmumformung in einem entsprechenden Pressenwerkzeug umgeformt. Anschließend wird das Blechprofil ausgehärtet, wobei es in dem Pressenwerkzeug verbleibt. Da das Blechprofil bei der im Zuge des Härtevorgangs vorgenommenen Kühlung im Pressenwerkzeug verbleibt und dort eingespannt ist, weist das derart hergestellte Produkt eine gute Maßhaltigkeit auf. Nachteilig an diesem Verfahren ist die lange Zykluszeit. Dabei wird die Dauer eines Verfahrenszyklus hauptsächlich bestimmt durch die Abkühlung des umgeformten Werkstückes im Umformwerkzeug. Auch bei maximaler Kühlleistung und einer optimierten Verteilung der Kühlkanäle im Werkzeug stellt der Abkühlvorgang innerhalb des Verfahrenszyklus den zeitlich dominierenden Anteil dar. Die DE 10 2005 003 551 Al offenbart ein Warmumformverfahren, bei dem als Endprodukt ein umgeformtes Blechteil mit einem Zwischenstufengefüge angestrebt wird. Erreicht wird dies durch ein Verfahren, welches für härtbare Feinbleche, vorzugsweise für Stahlbleche mit einem C-Gehalt von etwa 0,1 % bis etwa 0,3 % anwendbar ist. Das Verfahren zeichnet sich dadurch aus, dass im Anschluss an eine austenitisierende Erwärmung des Stahlbleches bis über den AC3-Punkt sich eine vergleichsweise rasche Abkühlung bis auf einen Temperaturbereich von 400° C bis 600° C anschließt. Mit Erreichen dieses Temperaturbereiches erfolgt eine isotherme Umformung des Blechs in seine Endform. Kennzeichnend für dieses Verfahren ist, dass vor der Umformung weder das Bainit-, noch das Ferrit-, noch das Perlit-, noch das Martensitgebiet erreicht wird, und dass die Umformung isotherm erfolgt bis das Zwischenstufengebiet erreicht wird und sich ein Zwischenstufengefüge einstellt.In DE 24 52 486 Al a direct mold hardening process for producing a hardened sheet metal profile from a circuit board is described. Thereafter, a sheet metal profile made of hardenable steel is heated to a hardening temperature. Subsequently, it is formed by means of a hot forming in a corresponding press tool. Subsequently, the sheet profile is cured leaving it in the press tool. Since the sheet metal profile remains in the press tool during the cooling process carried out in the course of the hardening process and is clamped there, the product produced in this way has a good dimensional stability. A disadvantage of this method is the long cycle time. The duration of a process cycle is mainly determined by the cooling of the formed workpiece in the forming tool. Even with maximum cooling capacity and an optimized distribution of the cooling channels in the tool, the cooling process within the process cycle represents the time dominating portion. DE 10 2005 003 551 A1 discloses a hot-forming process in which the end product is intended to be a formed sheet-metal part with an interstage structure. This is achieved by a method which is applicable to curable thin sheets, preferably for steel sheets with a C content of about 0.1% to about 0.3%. The method is characterized in that following a austenitizing heating of the steel sheet to above the A C3 point is followed by a comparatively rapid cooling to a temperature range of 400 ° C to 600 ° C. Upon reaching this temperature range, an isothermal deformation of the sheet into its final shape. Characteristic of this method is that before the transformation neither the bainite, nor the ferrite, nor the pearlite, nor the martensite is achieved, and that the transformation is made isothermal until the interstage area is reached and adjusts a Zwischenstufengefüge.
Aufgabe und Vorteile der ErfindungPurpose and advantages of the invention
Der Erfindung liegt die Aufgabe zugrunde, ausgehend vom Stand der Technik ein Formhärteverfahren zu entwickeln, welches eine deutliche Verkürzung der Verfahrenszykluszeit darstellt und welches als Endprodukt ein umgeformtes Blech mit definierten oder vorwählbaren Festigkeitswerten hat.The invention is based on the object, starting from the prior art to develop a mold hardening process, which represents a significant reduction in the process cycle time and which has as a final product a formed sheet with defined or preselected strength values.
Eine weitere Aufgabe der Erfindung ist die gezielte Einflussnahme auf das Fließverhalten des Werkstoffes zur Verhinderung von Falten und Reissern im umgeformten Werkstück.Another object of the invention is the targeted influence on the flow behavior of the material to prevent wrinkles and ripples in the formed workpiece.
Die Aufgabe wird ausgehend von einem Verfahren nach dem Oberbegriff des Anspruch 1 durch die kennzeichnenden Merkmale des Anspruch 1 gelöst. In den Unteransprüchen sind vorteilhafte und zweckmäßige Weiterbildungen des erfindungsgemäßen Verfahrens angegeben.The object is achieved on the basis of a method according to the preamble of claim 1 by the characterizing features of claim 1. In the subclaims are indicated advantageous and expedient developments of the method according to the invention.
Der Erfindung liegt der Gedanke zugrunde, zwischen dem Erwärmen und dem damit verbundenen Austenitisieren der Platinen bzw. vorgeformten Werkstücke und dem Abkühlen im Umformwerkzeug einen weiteren Prozessschritt einzuführen, um die Zeit zur Werkstückkühlung im Umformwerkzeug gegenüber bekannten Verfahren deutlich zu verkürzen. Hierbei werden die Platinen bzw. vorgeformten Werkstücke nach der Erwärmung zwischengekühlt bevor die vollständige Abkühlung in einem Umformwerkzeug erfolgt. Kennzeichnend für das erfindungsgemäße Warmumformverfahren ist, dass sowohl die Zwischenkühlung, als auch die Kühlung des umgeformten Werkstückes im Umformwerkzeug zeitlich so gesteuert werden, dass als Endprodukt ein umgeformtes Blech mit einem definierten Mischgefüge oder einem rein martensitischem Gefüge entsteht. Beide Abkühlungen müssen zeitlich genau definiert erfolgen, damit die gewünschten Gefügeumwandlungen entstehen.The invention is based on the idea to introduce a further process step between the heating and the associated austenitizing of the blanks or preformed workpieces and the cooling in the forming tool in order to significantly shorten the time for workpiece cooling in the forming tool compared to known methods. Here, the boards or preformed workpieces are cooled after the heating before the complete cooling takes place in a forming tool. Characteristic of the hot forming process according to the invention is that both the intermediate cooling, as well as the cooling of the formed workpiece in the forming tool are controlled in time so that the end product is a formed sheet with a defined mixed structure or a purely martensitic structure. Both coolings have to be precisely defined in terms of time, so that the desired microstructural transformations arise.
Da sich das Fließverhalten von Blechwerkstoffen temperaturabhängig ändert, ist es möglich durch eine gezielte Vorkühlung der gesamten Platine oder definierter Bereiche das Fließverhalten so zu beeinflussen, dass der Materialfluss des Werkstücks während der Umformung für die Bauteilherstellbar- keit optimiert wird. So können Reisser, Falten oder auch andere Defekte vermieden werden.Since the flow behavior of sheet metal materials changes depending on the temperature, it is possible to influence the flow behavior by targeted pre-cooling of the entire board or defined areas in such a way that the material flow of the workpiece is optimized during the forming process for component manufacturing. This way you can avoid tears, wrinkles or other defects.
Prinzipiell sieht die Erfindung zwei Arten von Zwischenkühlungen vor, durch Kontakt und durch Konvektion. Bei der Zwischenkühlung durch Kontaktkühlung werden im Durchlauf die Platinen an Kühlelementen vorbeigeführt, die beispielsweise als Kühlrollen und/oder plattenförmig ausgeführt sein können. Die Form der Kühlelemente sowie die Andruckkräfte der Platinen an die Kühlelemente bestimmen die Intensität der Kühlung. Die Erfindung umfasst Verfahren und Anlagen mit denen die Platinen gleichmäßig gekühlt werden sowie solche, bei denen eine partiell unterschiedliche Kühlung erfolgt.In principle, the invention provides for two types of intermediate cooling, by contact and by convection. In the intermediate cooling by contact cooling, the blanks are guided past cooling elements in the passage, which can be designed, for example, as cooling rollers and / or plate-shaped. The shape of the cooling elements and the pressure forces of the boards to the cooling elements determine the Intensity of cooling. The invention includes methods and systems with which the boards are cooled uniformly and those in which a partially different cooling takes place.
Das erfindungsgemäße Verfahren beinhaltet darüber hinaus die Möglichkeit die Zwischenkühlung unter Schutzgasatmosphäre durchzuführen um eine Verzunderung zu verhindern.The inventive method also includes the ability to perform the intermediate cooling under a protective gas atmosphere to prevent scaling.
Mögliche Bauformen dieser Anlagen können Ähnlichkeiten zu bekannten Richtmaschinen aufweisen, wobei bei der erfindungsgemäßen Zwischenkühlung im Gegensatz zum Richten nicht die plastische Verformung der Platinen das Ziel ist, sondern deren Kühlung.Possible designs of these systems may have similarities to known straightening machines, wherein in the inventive intermediate cooling in contrast to straightening not the plastic deformation of the boards is the goal, but their cooling.
Bei der Zwischenkühlung durch Konvektionskühlung werden die Werkstücke durch Anblasen mit Luft, speziellen Gasen, Sprühnebel oder Anstrahlen mit Flüssigkeiten gekühlt. Es sind Verfahren und Anlagen möglich, bei denen die Werkstücke im Durchlauf gekühlt werden und solche bei denen die Kühlung im Stillstand erfolgt. Wie bei der Kontaktkühlung ist es auch bei der Konvektionskühlung denkbar, dass die Werkstücke bzw. Platinen sowohl gleichmäßig als auch partiell unterschiedlich gekühlt werden.In the intermediate cooling by convection cooling, the workpieces are cooled by blowing with air, special gases, spray or sprayed with liquids. Processes and plants are possible in which the workpieces are cooled in a continuous process and those in which the cooling takes place at a standstill. As with contact cooling, it is also conceivable for convection cooling that the workpieces or sinkers are cooled both uniformly and partially differently.
Das erfindungsgemäße Verfahren beinhaltet auch die Verwendung und Bearbeitung von gefügten Platinen oder von Platinen mit partiell unterschiedlichen Dicken.The inventive method also includes the use and processing of joined boards or boards with partially different thicknesses.
Bei der Konvektionskühlung ist es vorteilhaft, wenn sich an der Oberfläche der angeströmten Platinen turbulente Strömungen bilden. Dadurch wird die Kühlwirkung verbessert. Weitere Einzelheiten und Vorteile der Erfindung ergeben sich aus den, anhand der Zeichnungen dargestellten Ausführungsbeispielen.In convection cooling, it is advantageous if turbulent flows form on the surface of the flown boards. This improves the cooling effect. Further details and advantages of the invention will become apparent from the embodiments illustrated by the drawings.
Es zeigen:Show it:
Figur 1 Prinzip einer Anlage für das erfindungsgemäße Verfahren zum Formhärten mit Zwischenkühlung durch Konvektion Figur 2 Prinzip einer Anlage für das erfindungsgemäße Verfahren zum Formhärten mit Zwischenkühlung durch KontaktFigure 1 Principle of a system for the inventive method for mold hardening with intermediate cooling by convection Figure 2 Principle of a system for the inventive method for mold hardening with intercooling by contact
Figur 3 Ausführungsbeispiel 1 einer KontaktkühlungFigure 3 Embodiment 1 of a contact cooling
Figur 4 Ausführungsbeispiel 2 einer Kontaktkühlung Figur 5 Ausführungsbeispiel 3 einer KontaktkühlungFigure 4 Embodiment 2 of a contact cooling Figure 5 Embodiment 3 of a contact cooling
Beschreibung der AusführungsbeispieleDescription of the embodiments
Figur 1 zeigt ein erstes Ausführungsbeispiel des erfindungsgemäßen Verfahrens zum Formhärten mit einer Zwischenkühlung durch Konvektion. Dabei wird zunächst eine Platine 1 von einem Platinenstapel 2 abgehoben und in einen Ofen 3 zugeführt. Der Transport der Platine 1 in den Ofen 3 und auch in die im Folgenden beschriebenenFigure 1 shows a first embodiment of the method according to the invention for mold hardening with an intermediate cooling by convection. In this case, first a circuit board 1 is lifted from a blank stack 2 and fed into a furnace 3. The transport of the board 1 in the furnace 3 and also in the following
Bearbeitungsstationen erfolgt mit marktüblichen im Stand der Technik bekannten Teiletransportsystemen . Der Ofen 3 kann beispielsweise als Rollenherdofen ausgeführt werden. Um eine Austenitisierung zu erreichen muss die Platine 1 bei Durchlaufen des Ofens 3 auf eine ausreichende Temperatur erhitzt werden. Anschließend wird die Platine 1 nicht wie beim konventionellen direkten Formhärten in ein kühlbares Umformwerkzeug eingelegt, sondern sie durchläuft eine Zwischenkühlungsstation 4. Die Zwischenkühlstation 4 besteht aus einer oder mehreren Kühlstufen 5, bei denen Luft oder spezielle Gase durch eine oder mehrere Öffnungen auf die Platine 1 geblasen werden und so eine Kühlwirkung erzielen. Diese Öffnungen können unterschiedliche Formen haben. Sie können beispielsweise als Bohrungen ausgeführt werden, aber auch alle anderen geometrischen Formen sind denkbar. Ebenfalls können in die Kühlstufen 5 Düsen eingebaut werden um die Kühlwirkung zu verbessern. Auch linienförmige Öffnungen sind denkbar, allerdings weisen diese häufig ungünstige Strömungsbedingungen auf.Processing stations are made using commercially available part transport systems known in the art. The furnace 3 can be carried out, for example, as a roller hearth furnace. In order to achieve austenitization, the board 1 must be heated to a sufficient temperature when passing through the furnace 3. Subsequently, the circuit board 1 is not inserted as in the conventional direct form hardening in a coolable forming tool, but it goes through a Intercooling station 4. The intermediate cooling station 4 consists of one or more cooling stages 5, in which air or special gases are blown through one or more openings on the board 1 and thus achieve a cooling effect. These openings can have different shapes. They can for example be performed as holes, but also all other geometric shapes are conceivable. Also, 5 nozzles can be installed in the cooling stages to improve the cooling effect. Even linear openings are conceivable, but these often have unfavorable flow conditions.
Nachdem die Platine 1 die Zwischenkühlungsstation durchlaufen hat, wird sie in eine Umformpresse 6 eingelegt. Schematisch dargestellt sind in Figur 1 ein Stößel 7 mit einemAfter the board 1 has passed through the intermediate cooling station, it is inserted into a forming press 6. Schematically represented in Figure 1, a plunger 7 with a
Oberwerkzeug 8 sowie ein Tisch 9 mit einem Unterwerkzeug 10. Bei der Umformpresse 6 handelt es sich in der Regel um eine hydraulische Presse, weil der Stößel 7 mit dem Oberwerkzeug 8 im unteren Umkehrpunkt mehrere Sekunden stehen bleiben muss. Neben hydraulischen Pressen können diese Anforderung auch Servopressen oder Kniehebelpressen erfüllen und sind somit auch für diese Formhärteverfahren geeignet. Nachdem die zwischengekühlte Platine 4 in das Unterwerkzeug 10 der Umformpresse 6 eingelegt wurde, bewegt sich der Stößel 7 mit dem Oberwerkzeug 8 nach unten und formt die Platine 4 zu deren Endkontur um. Nach Beenden des Umformvorganges bleibt das Werkzeug 8, 10 zunächst in geschlossenem Zustand. Während dieser Zeit wird die umgeformte Platine 4 so lange und so schnell gekühlt, bis sich im umgeformten Werkstück das gewünschte Gefüge einstellt. Durch die Abkühlung im geschlossenen Werkzeug 8, 10 bleibt die Form des Werkstückes stabil und es werden sehr gute Genauigkeiten am umgeformten Werkstück erreicht. Die Kühlung im Werkzeug 8, 10 erfolgt in der Regel mittels sich im Unterwerkzeug 10 und im Oberwerkzeug 8 befindliche Kühlkanäle. Die Zeitdauer der Kühlung in geschlossenen Werkzeug 8, 10 verringert sich beim erfindungsgemäßen Formhärteverfahren gegenüber den konventionellen Formhärteverfahren erheblich, weil aufgrund der Kühlung in der Zwischenkühlungsstation, die Wärmeenergie, welche im Kühlwerkzeug 8, 10 abgeführt werden muss, deutlich reduziert wird. Nachdem das umgeformte Werkstück eine gewünschte Temperatur erreicht hat, wird das umgeformte Werkstück aus der Umformpresse 6 entnommen und abgestapelt.Upper tool 8 and a table 9 with a lower tool 10. The forming press 6 is usually a hydraulic press, because the plunger 7 must remain with the upper tool 8 at the lower reversal point for several seconds. In addition to hydraulic presses, this requirement can also be met by servo presses or toggle presses and are thus also suitable for this form hardening method. After the intermediate-cooled board 4 has been inserted into the lower tool 10 of the forming press 6, the plunger 7 moves down with the upper tool 8 and forms the board 4 to its final contour. After completion of the forming process, the tool 8, 10 initially remains in the closed state. During this time, the deformed board 4 is cooled as long and so fast until the desired structure is established in the formed workpiece. By cooling in the closed mold 8, 10, the shape of the workpiece remains stable and it will be achieved very good accuracies on the formed workpiece. The cooling in the tool 8, 10 is usually carried out by means of the lower tool 10 and the upper tool 8 located cooling channels. The duration of the cooling in closed mold 8, 10 is significantly reduced in the inventive mold hardening process compared to the conventional mold hardening process, because due to the cooling in the intermediate cooling station, the heat energy which has to be dissipated in the cooling tool 8, 10 is significantly reduced. After the reshaped workpiece has reached a desired temperature, the formed workpiece is removed from the forming press 6 and stacked.
Figur 2 zeigt ein zweites Ausführungsbeispiel des erfindungsgemäßen Verfahrens zum Formhärten mit einer Zwischenkühlung durch Kontakt. Dieses zweite Ausführungsbeispiel unterscheidet sich vom ersten Ausführungsbeispiel durch die Art der Zwischenkühlung. Bei der Zwischenkühlungsstation 4 in Figur 2 handelt es sich um eine Kontaktkühlung. Dabei wird die Platine 1 durch den Kontakt mit Kühlrollen 11 gekühlt. Die Kühlrollen 11 sind in diesem Beispiel paarweise angeordnet. Die Paare von Kühlrollen 11 spannen die Platine 1 ein. Mindestens eines derFigure 2 shows a second embodiment of the method according to the invention for mold hardening with an intermediate cooling by contact. This second embodiment differs from the first embodiment by the type of intercooling. In the intermediate cooling station 4 in Figure 2 is a contact cooling. In this case, the board 1 is cooled by contact with cooling rollers 11. The cooling rollers 11 are arranged in pairs in this example. The pairs of cooling rollers 11 clamp the circuit board 1. At least one of
Kühlrollenpaare wird angetrieben, so dass die Platine 1 durch die Zwischenkühlstation 4 hindurchbefördert wird. Der Anpressdruck und die Form der Kühlrollen beeinflussen dabei die Kühlleistung. Als Kühlmedium zur Wärmeabfuhr aus den Kühlrollen 11 kommen prinzipiell alle gängigen Kühlmedien in Frage .Cooling roller pairs is driven, so that the board 1 is conveyed through the intermediate cooling station 4. The contact pressure and the shape of the cooling rollers affect the cooling capacity. As a cooling medium for heat removal from the cooling rollers 11 in principle all common cooling media in question.
In Figur 3, Figur 4 und Figur 5 sind unterschiedliche Varianten für die Anordnung der Kühlrollen 11 dargestellt. Bei der Anordnung in Figur 3 wird die Platine 1 von zwei kleineren Kühlrollen 13 gegen eine Kühlrolle 12 mit großem Durchmesser gedrückt. Der Vorteil dieser Anordnung ist, dass die Platine 1 die Kühlrolle 12 über einen großen Umschlingungswinkel berührt. Dadurch garantiert diese Anordnung eine gute Kühlleistung.In Figure 3, Figure 4 and Figure 5 different variants for the arrangement of the cooling rollers 11 are shown. In the arrangement in Figure 3, the board 1 is pressed by two smaller cooling rollers 13 against a cooling roller 12 with a large diameter. The advantage of this arrangement is that the board 1, the cooling roller 12 over a large wrap angle touched. As a result, this arrangement guarantees a good cooling performance.
In Figur 4 ist eine Kühlrollenanordnung dargestellt, welche der in Figur 2 entspricht. Die Kühlrollen 11 sind dabei paarweise angeordnet und üben von beiden Seiten eine Anpresskraft auf die Platine 1 aus. Hierdurch sind hohe Anpresskräfte möglich, welche eine gute Kühlleistung garantieren.FIG. 4 shows a cooling roller arrangement which corresponds to that in FIG. The cooling rollers 11 are arranged in pairs and exert a pressing force on the board 1 from both sides. As a result, high contact pressures are possible, which guarantee good cooling performance.
Figur 5 zeigt eine weitere Möglichkeit zur Anordnung der Kühlrollen. Im Unterschied zur Anordnung in Figur 4 sind die sich gegenüber liegenden Kühlrollen 14 versetzt zueinander angeordnet. Dadurch ergeben sich zwischen Platine und Kühlrollen größere Berührungsflächen, was sich vorteilhaft auf die Kühlleistung auswirkt.FIG. 5 shows a further possibility for arranging the cooling rollers. In contrast to the arrangement in Figure 4, the opposing cooling rollers 14 are arranged offset to one another. This results in larger contact surfaces between the board and cooling rollers, which has an advantageous effect on the cooling capacity.
Die Erfindung ist nicht auf dargestellte oder beschriebene Ausführungsbeispiele beschränkt. Sie umfasst vielmehr auch Weiterbildungen der Erfindung im Rahmen der Schutzrechtsansprüche . The invention is not limited to illustrated or described embodiments. Rather, it also includes developments of the invention within the scope of the patent claims.
B ClTezugszeichenlisteBC l Tezugzeichenliste
1 Platine1 board
2 Platinenstapel 3 Ofen2 stacks of boards 3 oven
4 ZwischenkühlungsStation4 intermediate cooling station
5 Kühlstufen5 cooling stages
6 Umformpresse6 forming press
7 Stößel 8 Oberwerkzeug7 pestle 8 upper tool
Tischtable
10 Unterwerkzeug10 lower tool
11 Kühlrollen11 cooling rollers
12 Kühlrollen 13 Kühlrollen12 cooling rollers 13 cooling rollers
14 Kühlrollen 14 cooling rollers
Claims
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE200810039264 DE102008039264A1 (en) | 2008-08-22 | 2008-08-22 | Method for tempering with intermediate cooling |
| DE102008039264.2 | 2008-08-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2010020212A1 true WO2010020212A1 (en) | 2010-02-25 |
Family
ID=41467121
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/DE2009/001108 Ceased WO2010020212A1 (en) | 2008-08-22 | 2009-08-07 | Method for mould annealing with intermediate cooling |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE102008039264A1 (en) |
| WO (1) | WO2010020212A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102011114764A1 (en) | 2011-10-01 | 2013-04-04 | Volkswagen Aktiengesellschaft | Method for preparing hardened components of motor vehicle, involves cooling secondary portion of plate by forced convection, while plate is in holding position for predetermined time and then cured in mold form hardening tool |
| WO2014114420A1 (en) * | 2013-01-23 | 2014-07-31 | Voestalpine Stahl Gmbh | Method for producing hardened components and a structural component produced using said method |
| EP2547798A4 (en) * | 2010-03-16 | 2016-12-28 | Gestamp Hardtech Ab | Press hardening plant and a method of press hardening a steel sheet blank |
| CN107321832A (en) * | 2017-07-10 | 2017-11-07 | 山东钢铁集团日照有限公司 | A kind of process of steady decrease thermoforming temperatures |
| US10449597B2 (en) | 2014-01-30 | 2019-10-22 | Thyssenkrupp Steel Europe Ag | Method for the surface treatment of a workpiece |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103403195B (en) | 2011-01-17 | 2016-05-04 | 塔塔钢铁艾默伊登有限责任公司 | A method for thermoforming parts, and the parts of moulding like this |
| DE102014204639A1 (en) * | 2014-03-13 | 2015-09-17 | Bayerische Motoren Werke Aktiengesellschaft | Method for producing at least one dimensionally hardened workpiece and manufacturing device for producing at least one dimensionally hardened workpiece |
| DE102014114740B3 (en) * | 2014-10-10 | 2015-07-23 | Schuler Pressen Gmbh | Process for producing hardened steel components |
| DE102015203406A1 (en) * | 2015-02-26 | 2016-09-01 | Bayerische Motoren Werke Aktiengesellschaft | Plant for mass production of press-hardened and corrosion-protected sheet metal parts, with a cooling device for intermediate cooling of the boards |
| EP3067129A1 (en) | 2015-03-09 | 2016-09-14 | Autotech Engineering, A.I.E. | Press systems and methods |
| PT3067128T (en) | 2015-03-09 | 2017-11-14 | Autotech Eng A I E | Press system for die quenching and method |
| DE102017107549A1 (en) | 2017-04-07 | 2018-10-11 | Schwartz Gmbh | Temperature control station for the partial heat treatment of a metallic component |
| DE102017213000A1 (en) * | 2017-07-27 | 2019-01-31 | Bayerische Motoren Werke Aktiengesellschaft | Forming process for a sheet metal component |
| DE102020116126A1 (en) | 2020-06-18 | 2021-12-23 | Bilstein Gmbh & Co. Kg | Process for press hardening of hot-formable blanks |
| DE102021122383A1 (en) | 2021-08-30 | 2023-03-02 | Audi Aktiengesellschaft | Process for the production of a hot-formed and press-hardened sheet steel component |
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| DE10208216C1 (en) * | 2002-02-26 | 2003-03-27 | Benteler Automobiltechnik Gmbh | Production of a hardened metallic component used as vehicle component comprises heating a plate or a pre-molded component to an austenitizing temperature, and feeding via a transport path while quenching parts of plate or component |
| DE102005003551A1 (en) * | 2005-01-26 | 2006-07-27 | Volkswagen Ag | Steel sheet forming and hardening, comprises austenitic heating above the Ac3 point, followed by forming and cooling |
| WO2008104360A1 (en) * | 2007-03-01 | 2008-09-04 | Schuler Smg Gmbh & Co. Kg | Method for shaping a blank, and cooling device for a blank |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE435527B (en) | 1973-11-06 | 1984-10-01 | Plannja Ab | PROCEDURE FOR PREPARING A PART OF Hardened Steel |
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2008
- 2008-08-22 DE DE200810039264 patent/DE102008039264A1/en not_active Ceased
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- 2009-08-07 WO PCT/DE2009/001108 patent/WO2010020212A1/en not_active Ceased
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10208216C1 (en) * | 2002-02-26 | 2003-03-27 | Benteler Automobiltechnik Gmbh | Production of a hardened metallic component used as vehicle component comprises heating a plate or a pre-molded component to an austenitizing temperature, and feeding via a transport path while quenching parts of plate or component |
| DE102005003551A1 (en) * | 2005-01-26 | 2006-07-27 | Volkswagen Ag | Steel sheet forming and hardening, comprises austenitic heating above the Ac3 point, followed by forming and cooling |
| WO2008104360A1 (en) * | 2007-03-01 | 2008-09-04 | Schuler Smg Gmbh & Co. Kg | Method for shaping a blank, and cooling device for a blank |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2547798A4 (en) * | 2010-03-16 | 2016-12-28 | Gestamp Hardtech Ab | Press hardening plant and a method of press hardening a steel sheet blank |
| DE102011114764A1 (en) | 2011-10-01 | 2013-04-04 | Volkswagen Aktiengesellschaft | Method for preparing hardened components of motor vehicle, involves cooling secondary portion of plate by forced convection, while plate is in holding position for predetermined time and then cured in mold form hardening tool |
| DE102011114764B4 (en) * | 2011-10-01 | 2016-04-21 | Volkswagen Aktiengesellschaft | Process for the production of form-hardened components and continuous furnace for heating a board provided for molding |
| WO2014114420A1 (en) * | 2013-01-23 | 2014-07-31 | Voestalpine Stahl Gmbh | Method for producing hardened components and a structural component produced using said method |
| US10449597B2 (en) | 2014-01-30 | 2019-10-22 | Thyssenkrupp Steel Europe Ag | Method for the surface treatment of a workpiece |
| CN107321832A (en) * | 2017-07-10 | 2017-11-07 | 山东钢铁集团日照有限公司 | A kind of process of steady decrease thermoforming temperatures |
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| Publication number | Publication date |
|---|---|
| DE102008039264A1 (en) | 2010-03-04 |
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