EP0163906A2 - Method and vacuum furnace for heat treatment a charge - Google Patents

Method and vacuum furnace for heat treatment a charge Download PDF

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Publication number
EP0163906A2
EP0163906A2 EP85104965A EP85104965A EP0163906A2 EP 0163906 A2 EP0163906 A2 EP 0163906A2 EP 85104965 A EP85104965 A EP 85104965A EP 85104965 A EP85104965 A EP 85104965A EP 0163906 A2 EP0163906 A2 EP 0163906A2
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EP
European Patent Office
Prior art keywords
heating chamber
gas
heating
batch
charge
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Granted
Application number
EP85104965A
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German (de)
French (fr)
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EP0163906A3 (en
EP0163906B1 (en
Inventor
Peter Schmetz
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Schmetz GmbH and Co KG
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Schmetz GmbH and Co KG
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Priority to AT85104965T priority Critical patent/ATE37201T1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B5/00—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated
    • F27B5/06—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B5/16—Arrangements of air or gas supply devices
    • 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
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • 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
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/773—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material under reduced pressure or vacuum
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B5/00—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated
    • F27B5/06—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B2005/062—Cooling elements
    • F27B2005/064—Cooling elements disposed in the furnace, around the chamber, e.g. coils
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B5/00—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated
    • F27B5/06—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B5/14—Arrangements of heating devices
    • F27B2005/143—Heating rods disposed in the chamber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B5/00—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated
    • F27B5/06—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B5/16—Arrangements of air or gas supply devices
    • F27B2005/161—Gas inflow or outflow
    • F27B2005/162—Gas inflow or outflow through closable or non-closable openings of the chamber walls
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B5/00—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated
    • F27B5/06—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B5/16—Arrangements of air or gas supply devices
    • F27B2005/166—Means to circulate the atmosphere
    • F27B2005/167—Means to circulate the atmosphere the atmosphere being recirculated through the treatment chamber by a turbine

Definitions

  • the invention relates to a method for the heat treatment of a batch of metallic workpieces or a single workpiece in a closable and evacuable container.
  • the invention further relates to a vacuum furnace for carrying out the method with a closable steel container and an internal heating chamber for receiving the batch, with a heating device located within the heating chamber and with a gas blower and a gas guide device for generating a circulation flow through the heating chamber.
  • the object of the invention is accordingly to provide a method for the heat treatment of a batch, which enables faster heating and with which a uniform heat distribution within the batch is achieved at the same time.
  • the object of the invention is also to propose a vacuum oven suitable for carrying out this method.
  • the first-mentioned object is achieved according to the invention in that the container is evacuated after the batch is inserted and flooded with protective gas, the batch is then heated by heating and gas circulation up to the maximum permissible working temperature of the circulating device and then essentially with static protective gas or under vacuum heated by radiant heat to a desired final temperature of the heat treatment becomes.
  • the batch is heated in a first stage by hot gas circulation, i.e. essentially by convection heat up to a temperature permissible for the circulation device, and in a subsequent second stage either under static protective gas or under vacuum, essentially by radiant heat to the desired final temperature.
  • hot gas circulation i.e. essentially by convection heat up to a temperature permissible for the circulation device
  • second stage either under static protective gas or under vacuum, essentially by radiant heat to the desired final temperature.
  • the circulating device is protected in a suitable manner against the effects of the higher temperatures.
  • the invention is based on a vacuum furnace with a lockable steel container and an internal heating chamber for receiving the batch, with a heating device located within the heating chamber and with a gas blower and a gas guide device for generating a circulation flow through the heating chamber.
  • the heating chamber can be closed according to the invention with the exclusion of the gas blower for heating the batch in the second stage.
  • Such a vacuum furnace is flooded with protective gas in the first treatment stage.
  • This protective gas is circulated with the aid of the fan of the gas blower projecting into the heating chamber and the gas guiding device in the boiler room in such a way that the energy from the heating elements is also transmitted convectively to the batch to be heated in addition to radiation.
  • the maximum working temperature of the fan is reached, it is moved out of the heating chamber and the opening is closed by a slide.
  • the batch can be heated to the desired final temperature either under a protective gas atmosphere or - after another evacuation - under vacuum.
  • a vacuum shaft furnace with vertical loading was chosen for the description of an exemplary embodiment.
  • This furnace consists of a cylindrical lower part 1, which stands on the floor with a support structure 2, and an upper part 3, which is detachably connected to the lower part 1 in the parting plane 4.
  • On top 3 is on the top of a hood 5 attached by means of a flange connection.
  • a lifting and swiveling device 6 is provided which rests on the floor with one foot and is connected to the lower part 1 on its side wall.
  • Lower part 1 and upper part 3 consist of sheet steel and form a vacuum-tight container in the operating position.
  • a likewise cylindrical heating chamber 7 is arranged in the interior of this container, the walls of which are equipped with a thermal insulation layer 8.
  • the bottom 9 of the heating chamber 7 can be lowered. It rests on the ends of piston rods of lifting cylinders 10 which are fastened in the bottom of the lower furnace part 1. With the aid of the lifting cylinders, the base 9 can be moved from the closed position into an open position and vice versa, as is shown in the two half-sections in FIG. 1.
  • a support grate 12 is provided in the interior of the heating chamber 7, which is supported on the bottom of the lower part 1 by means of a support structure 13 consisting essentially of vertical supports.
  • a support structure 13 consisting essentially of vertical supports.
  • openings are contained in which the vertical supports of the support structure 13 are slidably guided.
  • cooling tubes 14 are arranged, for example in the form of a spiral made of finned tubes. Inside the heating chamber 7 there are heating elements 15, for example electrical resistance heating elements, near the inner lateral surface. Furthermore, a gas guiding device 16 is provided in the interior of the heating chamber 7 and is located in the space between the heating elements 15 and the charge 11. This gas pipe device is guided upwards like a hood to the center, a central opening 17 being left open.
  • a slide 25 is provided which, like the wall of the heating chamber 7, is equipped with a heat insulation layer. This slide 25 can be moved back and forth from the operating position shown in FIG. 2 into a lateral rest position.
  • a laterally projecting nozzle 26 is formed on the upper part 3.
  • the subsequent cooling is again carried out with gas circulation.
  • the slide 25 is opened and the fan motor 18 is lowered into the intermediate position shown in the right half section of FIG. 1.
  • the bottom 9 of the heating chamber 7 is further lowered, as is also shown in the right half section of FIG. 1.
  • the gas is now again ventilated with the help of the fan 19 into a circulation flow upwards out of the heating chamber 7 into the space between the heating chamber 7 and the lower part 1 past the cooling tubes 14 and here into the interior of the heating chamber 7 set back.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Furnace Details (AREA)
  • Muffle Furnaces And Rotary Kilns (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Drying Of Solid Materials (AREA)

Abstract

A method and vacuum furnace for heat-treating a charge. Pursuant to the method, after the charge is placed in the receiving vessel, the latter is evacuated and flooded with inert gas. Subsequently, the charge is heated to the maximum permissible operating temperature of the circulation device by heating and gas circulation. Thereafter, the charge is heated to the desired end temperature by static inert gas or under vacuum, and essentially by radiation heat. The vacuum furnace may include a steel vessel which can be closed off, and which contains an inner heating chamber for receiving the charge. A heating device is provided within the heating chamber, and a fan and a gas guiding arrangement are provided for producing a gas circulation through the heating chamber. In the second phase, in which the heating is effected by radiant heat, the heating chamber can be closed off, accompanied by disconnection of the fan. For this purpose, an opening is provided in the wall of the heating chamber. This opening can be closed off by a sliding plug.

Description

Die Erfindung betrifft ein Verfahren zur Wärmebehandlung einer Charge aus metallischen Werkstücken oder einem einzigen Werkstück in einem verschließbaren und evakuierbaren Behälter. Weiter betrifft die Erfindung einen Vakuumofen zur Durchführung des Verfahrens mit einem verschließbaren Stahlbehälter und einer inneren Heizkammer zur Aufnahme der Charge, mit einer innerhalb der Heizkammer befindlichen Heizeinrichtung und mit einem Gasgebläse sowie einer Gasleiteinrichtung zur Erzeugung einer Umwälzströmung durch die Heizkammer.The invention relates to a method for the heat treatment of a batch of metallic workpieces or a single workpiece in a closable and evacuable container. The invention further relates to a vacuum furnace for carrying out the method with a closable steel container and an internal heating chamber for receiving the batch, with a heating device located within the heating chamber and with a gas blower and a gas guide device for generating a circulation flow through the heating chamber.

Vakuumöfen dieser Art sind bekannt. Beim Erwärmen einer Charge im Vakuum erfolgt die Energieübertragung fast ausschließlich durch Strahlung. Die übertragbare Energie ist dabei abhängig von der Höhe der Temperatur. In der Praxis bedeutet dies, daß die Erwärmung bis etwa 750° C sehr langsam erfolgt. Außerdem treten Schatteneffekte auf, die eine angestrebte gleichmäßige Erwärmung der Charge erschweren.Vacuum furnaces of this type are known. When a batch is heated in a vacuum, the energy transfer takes place almost exclusively through radiation. The transferable energy depends on the temperature. In practice, this means that the heating up to about 750 ° C takes place very slowly. There are also shadow effects that make it difficult to heat the batch uniformly.

Die Aufgabe der Erfindung besteht dementsprechend darin, für die Wärmebehandlung einer Charge ein Verfahren anzugeben, welches eine schnellere Erwärmung ermöglicht und mit dem zugleich eine gleichmäßige Wärmeverteilung innerhalb der Charge erzielt wird. Aufgabe der Erfindung ist es ferner, einen für die Durchführung dieses Verfahrens geeigneten Vakuumofen vorzuschlagen.The object of the invention is accordingly to provide a method for the heat treatment of a batch, which enables faster heating and with which a uniform heat distribution within the batch is achieved at the same time. The object of the invention is also to propose a vacuum oven suitable for carrying out this method.

Die erstgenannte Aufgabe wird erfindungsgemäß dadurch gelöst, daß der Behälter nach dem Einsetzen der Charge evakuiert und mit Schutzgas geflutet wird, die Charge anschließend durch Heizen und Gasumwälzung bis auf die maximal zulässige Arbeitstemperatur der Umwälzeinrichtung erwärmt wird und hiernach mit ruhendem Schutzgas oder unter Vakuum im wesentlichen durch Strahlungswärme auf eine gewünschte Endtemperatur der Wärmebehandlung erwärmt wird.The first-mentioned object is achieved according to the invention in that the container is evacuated after the batch is inserted and flooded with protective gas, the batch is then heated by heating and gas circulation up to the maximum permissible working temperature of the circulating device and then essentially with static protective gas or under vacuum heated by radiant heat to a desired final temperature of the heat treatment becomes.

Nach diesem Verfahren erfolgt das Erwärmen der Charge in einer ersten Stufe durch Heißgasumwälzen, also im wesentlichen durch Konvektionswärme bis zu einer für die Umwälzeinrichtung zulässigen Temperatur und in einer anschließenden zweiten Stufe entweder unter ruhendem Schutzgas oder unter Vakuum im wesentlichen durch Strahlungswärme bis zur gewünschten Endtemperatur. Vor Beginn der zweiten Stufe wird die Umwälzeinrichtung auf eine geeignete Art gegen die Einwirkung der höheren Temperaturen geschützt. Ein solches Verfahren ermöglicht eine insgesamt schnellere und gleichmäßigere Erwärmung einer Charge als nach den herkömmlichen Verfahren.According to this method, the batch is heated in a first stage by hot gas circulation, i.e. essentially by convection heat up to a temperature permissible for the circulation device, and in a subsequent second stage either under static protective gas or under vacuum, essentially by radiant heat to the desired final temperature. Before the start of the second stage, the circulating device is protected in a suitable manner against the effects of the higher temperatures. Such a method enables a batch to be heated more quickly and more uniformly than in the conventional methods.

Für die konstruktive Lösung geht die Erfindung aus von einem Vakuumofen mit einem verschließbaren Stahlbehälter und einer inneren Heizkammer zur Aufnahme der Charge, mit einer innerhalb der Heizkammer befindlichen Heizeinrichtung und mit einem Gasgebläse sowie einer Gasleiteinrichtung zur Erzeugung einer Umwälzströmung durch die Heizkammer. Bei diesem Vakuumofen ist für die Erwärmung der Charge in der zweiten Stufe erfindungsgemäß die Heizkammer unter Ausschluß des Gasgebläses verschließbar.For the constructive solution, the invention is based on a vacuum furnace with a lockable steel container and an internal heating chamber for receiving the batch, with a heating device located within the heating chamber and with a gas blower and a gas guide device for generating a circulation flow through the heating chamber. In this vacuum oven, the heating chamber can be closed according to the invention with the exclusion of the gas blower for heating the batch in the second stage.

Gemäß einer vorteilhaften Ausführung ist in der Wandung der Heizkammer eine Öffnung enthalten, die durch einen Schieber verschließbar ist, und wobei das Gasgebläse zwischen einer Ruhe- und einer Arbeitsstellung derart hin-und her bewegbar gelagert ist, daß der Ventilator in der Ruhestellung außerhalb der Heizkammer liegt, dagegen in der Arbeitsstellung bei geöffnetem Schieber in das Innere der Heizkammer hineinragt. Weiter ist hierbei auf der Rückseite des Ventilators ein Stopfen mit integrierter Wärmedämmschicht angebracht, der zum Verschließen der Öffnung dient, wenn der Ventilator die Arbeitsstellung einnimmt.According to an advantageous embodiment, an opening is contained in the wall of the heating chamber, which can be closed by a slide, and the gas blower is mounted so that it can move back and forth between a rest and a working position in such a way that the fan is in the rest position outside the heating chamber lies, however, protrudes into the interior of the heating chamber in the working position with the slide open. Furthermore, a plug with integrated thermal insulation layer is attached to the back of the fan, which is used to close the opening when the fan is in the working position occupies.

Ein solcher Vakuumofen ist in der ersten Behandlungsstufe mit Schutzgas geflutet. Dieses Schutzgas wird mit Hilfe des in die Heizkammer hineinragenden Ventilators des Gasgebläses und der Gasleiteinrichtung im Heizraum derart umgewälzt, daß die Energie von den Heizelementen außer durch Strahlung auch konvektiv auf die zu erwärmende Charge übertragen wird. Sobald die maximale Arbeitstemperatur des Ventilators erreicht ist, wird dieser aus der Heizkammer herausgefahren und die Öffnung durch einen Schieber verschlossen. Danach kann in der zweiten Stufe die Charge entweder unter ruhender Schutzgasatmosphäre oder - nach erneuter Evakuierung - unter Vakuum auf die gewünschte Endtemperatur erwärmt werden.Such a vacuum furnace is flooded with protective gas in the first treatment stage. This protective gas is circulated with the aid of the fan of the gas blower projecting into the heating chamber and the gas guiding device in the boiler room in such a way that the energy from the heating elements is also transmitted convectively to the batch to be heated in addition to radiation. As soon as the maximum working temperature of the fan is reached, it is moved out of the heating chamber and the opening is closed by a slide. Then in the second stage the batch can be heated to the desired final temperature either under a protective gas atmosphere or - after another evacuation - under vacuum.

Die Erfindung wird nachstehend an einem in der Zeichnung schematisch dargestellten Vakuumschachtofen näher erläutert. Es zeigen:

  • Fig. 1 einen senkrechten Schnitt des Vakuumschachtofens, bei dem im linken Halbschnitt die Betriebsstellung "Heizen mit Gasumwälzung" und im rechten Halbschnitt die Betriebsstellung "Kühlen mit Gasumwälzung" dargestellt ist, und
  • Fig. 2 einen senkrechten Schnitt des Vakuumschachtofens entsprechend der Betriebsstellung "Heizen unter Ausschluß des Gasgebläses".
The invention is explained in more detail below on a vacuum shaft furnace shown schematically in the drawing. Show it:
  • Fig. 1 is a vertical section of the vacuum shaft furnace, in which the operating position "heating with gas circulation" and the operating position "cooling with gas circulation" is shown in the left half section, and
  • Fig. 2 is a vertical section of the vacuum shaft furnace corresponding to the operating position "heating with the gas blower excluded".

Für die Beschreibung eines Ausführungsbeispieles wurde ein Vakuumschachtofen mit vertikaler Beschickung gewählt. Dieser Ofen besteht aus einem zylindrischen Unterteil 1, der mit einer Trägerkonstruktion 2 auf dem Boden steht, und einem Oberteil 3, der in der Trennebene 4 mit dem Unterteil 1 lösbar verbunden ist. Am Oberteil 3 ist auf der Oberseite eine Haube 5 mittels einer Flanschverbindung befestigt. Für das Abheben des Oberteils 3 vom Unterteil 1 und das seitliche Ausschwenken ist eine Heb- und Schwenkeinrichtung 6 vorgesehen, die mit einem Fuß auf dem Boden ruht und mit dem Unterteil 1 an dessen Seitenwand verbunden ist.A vacuum shaft furnace with vertical loading was chosen for the description of an exemplary embodiment. This furnace consists of a cylindrical lower part 1, which stands on the floor with a support structure 2, and an upper part 3, which is detachably connected to the lower part 1 in the parting plane 4. On top 3 is on the top of a hood 5 attached by means of a flange connection. For lifting the upper part 3 from the lower part 1 and swiveling it out to the side, a lifting and swiveling device 6 is provided which rests on the floor with one foot and is connected to the lower part 1 on its side wall.

Unterteil 1 und Oberteil 3 bestehen aus Stahlblech und bilden in der Betriebsstellung einen vakuumdicht abgeschlossenen Behälter. Im Innern dieses Behälters ist eine ebenfalls zylindrische Heizkammer 7 angeordnet, deren Wandungen mit einer Wärmedämmschicht 8 ausgestattet sind. Der Boden 9 der Heizkammer 7 ist absenkbar. Er ruht auf den Enden von Kolbenstangen von Hubzylindern 10, die im Boden des Ofenunterteils 1 befestigt sind. Mit Hilfe der Hubzylinder kann der Boden 9 aus der Schließstellung in eine Offenstellung und umgekehrt bewegt werden, wie es in den beiden Halbschnitten in Fig. 1 dargestellt ist.Lower part 1 and upper part 3 consist of sheet steel and form a vacuum-tight container in the operating position. A likewise cylindrical heating chamber 7 is arranged in the interior of this container, the walls of which are equipped with a thermal insulation layer 8. The bottom 9 of the heating chamber 7 can be lowered. It rests on the ends of piston rods of lifting cylinders 10 which are fastened in the bottom of the lower furnace part 1. With the aid of the lifting cylinders, the base 9 can be moved from the closed position into an open position and vice versa, as is shown in the two half-sections in FIG. 1.

Für das Auflegen der Charge 11, die in der Zeichnung durch ein Rechteck angedeutet ist, ist im Innern der Heizkammer 7 ein Auflagerost 12 vorgesehen, der mit Hilfe einer im wesentlichen aus senkrechten Stützen bestehenden Tragkonstruktion 13 am Boden des Unterteils 1 abgestützt ist. In dem heb- und senkbaren Boden 9 der Heizkammer 7 sind Öffnungen enthalten, in denen die senkrechten Stützen der Tragkonstruktion 13 gleitend geführt sind.For placing the batch 11, which is indicated in the drawing by a rectangle, a support grate 12 is provided in the interior of the heating chamber 7, which is supported on the bottom of the lower part 1 by means of a support structure 13 consisting essentially of vertical supports. In the lifting and lowering bottom 9 of the heating chamber 7 openings are contained in which the vertical supports of the support structure 13 are slidably guided.

In dem Zwischenraum zwischen dem Unterteil 1 und der Heizkammer 7 sind Kühlrohre 14, beispielsweise in Form einer Wendel aus Rippenrohren angeordnet. Im Innern der Heizkammer 7 befinden sich nahe der inneren Mantelfläche Heizelemente 15, z.B. elektrische Widerstandsheizelemente. Weiter ist im Innern der Heizkammer 7 eine Gasleiteinrichtung 16 vorgesehen, die sich im Zwischenraum zwischen den Heizelementen 15 und der Charge 11 befindet. Diese Gasleiteinrichtung ist nach oben haubenartig zur Mitte geführt, wobei eine zentrale Öffnung 17 freigelassen ist.In the space between the lower part 1 and the heating chamber 7, cooling tubes 14 are arranged, for example in the form of a spiral made of finned tubes. Inside the heating chamber 7 there are heating elements 15, for example electrical resistance heating elements, near the inner lateral surface. Furthermore, a gas guiding device 16 is provided in the interior of the heating chamber 7 and is located in the space between the heating elements 15 and the charge 11. This gas pipe device is guided upwards like a hood to the center, a central opening 17 being left open.

Innerhalb der oberen Haube 5 befindet sich ein Ventilatormotor 18, der am Ende der nach unten ragenden Motorwelle ein Flügelrad 19 trägt. Der Ventilatormotor 18 ist am freien Ende einer Kolbenstange eines Hubzylinders 20 befestigt und mit Hilfe dieses Hubzylinders aus einer oberen Ruhestellung in eine untere Betriebsstellung absenkbar und umgekehrt. Ebenso wie in der Gasleiteinrichtung 16 ist in der oberen Decke der Heizkammer eine etwa gleich große Öffnung 21 enthalten, durch die das Flügelrad 19 in das Innere der Heizkammer 7 eindringen kann. Über ein Gestänge 22 ist an der Kolbenstange des Hubzylinders 20 ein kreisrunder Stopfen 23 mit entsprechender Wärmedämmschicht befestigt, der in der Betriebsstellung des Ventilatormotors 18 die Öffnung 21 der Heizkammer 7 verschließt. Weiter ist auf der Rückseite des Stopfens 23 eine Kühlscheibe 24 für die Welle des Ventilatormotors 18 vorgesehen, der ebenfalls am Gestänge 22 befestigt ist.Inside the upper hood 5 there is a fan motor 18 which carries an impeller 19 at the end of the motor shaft projecting downwards. The fan motor 18 is attached to the free end of a piston rod of a lifting cylinder 20 and can be lowered with the aid of this lifting cylinder from an upper rest position into a lower operating position and vice versa. Just as in the gas guiding device 16, an opening 21 of approximately the same size is contained in the upper ceiling of the heating chamber, through which the impeller 19 can penetrate into the interior of the heating chamber 7. A circular stopper 23 with a corresponding thermal barrier coating is fastened to the piston rod of the lifting cylinder 20 via a linkage 22 and closes the opening 21 of the heating chamber 7 in the operating position of the fan motor 18. Furthermore, a cooling disk 24 is provided for the shaft of the fan motor 18 on the back of the plug 23, which is also attached to the linkage 22.

Für das Verschließen der Heizkammer in der Betriebsphase, in der der Ventilatormotor 18 die Ruhestellung einnimmt, ist ein Schieber 25 vorgesehen, der wie die Wandung der Heizkammer 7 mit einer Wärmedämmschicht ausgestattet ist. Dieser Schieber 25 ist aus der in Fig. 2 dargestellten Einsatzstellung in eine seitliche Ruhestellung hin- und her bewegbar. Zu diesem Zweck ist am Oberteil 3 ein seitlich vorstehender Stutzen 26 angeformt.For closing the heating chamber in the operating phase, in which the fan motor 18 assumes the rest position, a slide 25 is provided which, like the wall of the heating chamber 7, is equipped with a heat insulation layer. This slide 25 can be moved back and forth from the operating position shown in FIG. 2 into a lateral rest position. For this purpose, a laterally projecting nozzle 26 is formed on the upper part 3.

Für die Wärmebehandlung einer Charge wird der beschriebene Vakuumschachtofen wie folgt eingesetzt:

  • Der linke Halbschnitt in Fig. 1 zeigt den Betriebszustand für das Heizen mit Gasumwälzung bis zu einer Temperatur von etwa 750° C. Der Ventilatormotor 18 nimmt die untere Betriebsstellung ein, in der der Ventilator 19 in Höhe der Öffnung 17 der Gasleiteinrichtung 16 sich befindet. Das im Innern der Heizkammer befindliche Schutzgas wird in eine Umwälzströmung aus dem Innenraum der Gasleiteinrichtung 16 nach oben in den Zwischenraum zwischen Gasleiteinrichtung 16 und Wandung der Heizkammer 7 versetzt, wobei der Gasstrom an den Heizelementen 15 erwärmt wird und am unteren Ende des Zwischenraumes erneut in das Innere der Gasleiteinrichtung 16 eintritt. Wenn die für den Ventilator 19 maximal zulässige Temperatur erreicht ist, wird der Ventilatormotor 18 in die in Fig. 2 dargestellte Ruhestellung zurückbewegt. Mit dem Schieber 25 wird die Öffnung 21 der Heizkammer 7 verschlossen. In dieser Phase wird die Charge 11 mit ruhendem Schutzgas oder unter Vakuum im wesentlichen durch Strahlungswärme bis zur gewünschten Endtemperatur, z.B. 1.150° C, erwärmt.
The described vacuum shaft furnace is used for the heat treatment of a batch as follows:
  • The left half section in Fig. 1 shows the operating state for heating with gas circulation up to a temperature of about 750 ° C. The fan motor 18 assumes the lower operating position, in which the fan 19 is at height the opening 17 of the gas guide device 16 is located. The protective gas inside the heating chamber is placed in a circulating flow from the interior of the gas guiding device 16 upwards into the space between the gas guiding device 16 and the wall of the heating chamber 7, the gas flow being heated at the heating elements 15 and again at the lower end of the space Inside the gas guide device 16 occurs. When the maximum permissible temperature for the fan 19 is reached, the fan motor 18 is moved back into the rest position shown in FIG. 2. The opening 21 of the heating chamber 7 is closed with the slide 25. In this phase, the batch 11 is heated with inert gas or under vacuum, essentially by radiant heat, to the desired final temperature, for example 1,150 ° C.

Das nachfolgende Kühlen erfolgt wiederum mit Gasumwälzung. Zu diesem Zweck wird der Schieber 25 geöffnet und der Ventilatormotor 18 in die im rechten Halbschnitt der Fig. 1 dargestellte Zwischenstellung abgesenkt. Weiter wird der Boden 9 der Heizkammer 7 nach unten abgesenkt, wie es ebenfalls im rechten Halbschnitt der Fig. 1 daraestellt ist. In Verbindung mit der Gasleiteinrichtung 16 wird nun das Gas mit Hilfe des Ventilators 19 erneut in eine Umwälzströmung nach oben aus der Heizkammer 7 heraus in den Zwischenraum zwischen Heizkammer 7 und Unterteil 1 an den Kühlrohren 14 vorbei nach unten und hier in das Innere der Heizkammer 7 zurückversetzt.The subsequent cooling is again carried out with gas circulation. For this purpose, the slide 25 is opened and the fan motor 18 is lowered into the intermediate position shown in the right half section of FIG. 1. The bottom 9 of the heating chamber 7 is further lowered, as is also shown in the right half section of FIG. 1. In connection with the gas guide device 16, the gas is now again ventilated with the help of the fan 19 into a circulation flow upwards out of the heating chamber 7 into the space between the heating chamber 7 and the lower part 1 past the cooling tubes 14 and here into the interior of the heating chamber 7 set back.

Claims (4)

1. Verfahren zur Wärmebehandlung einer Charge aus metallischen Werkstücken oder einem einzigen Werkstück in einem verschließbaren und evakuierbaren Behälter, dadurch gekennzeichnet, daß der Behälter nach dem Einsetzen der Charge evakuiert und mit Schutzgas geflutet wird, die Charge anschließend durch Heizen und Gasumwälzung bis auf die maximal zulässige Arbeitstemperatur der Umwälzeinrichtung erwärmt wird und hiernach mit ruhendem Schutzgas oder unter Vakuum im wesentlichen durch Strahlungswärme auf eine gewünschte Endtemperatur der Wärmebehandlung erwärmt wird.1. A method for the heat treatment of a batch of metallic workpieces or a single workpiece in a sealable and evacuable container, characterized in that the container is evacuated after the batch is inserted and flooded with protective gas, the batch is then heated to the maximum by heating and gas circulation permissible working temperature of the circulating device is heated and then heated to a desired final temperature of the heat treatment with inert gas or under vacuum, essentially by radiant heat. 2. Vakuumofen zur Durchführung des Verfahrens nach Anspruch 1 mit einem verschließbaren Stahlbehälter und einer inneren Heizkammer zur Aufnahme der Charge, mit einer innerhalb der Heizkammer befindlichen Heizeinrichtung und mit einem Gasgebläse sowie einer Gasleiteinrichtung zur Erzeugung einer Umwälzströmung durch die Heizkammer, dadurch gekennzeichnet, daß die Heizkammer (7) unter Ausschluß des Gasgebläses (18, 19) verschließbar ist.2. Vacuum furnace for performing the method according to claim 1 with a closable steel container and an inner heating chamber for receiving the batch, with a heating device located within the heating chamber and with a gas blower and a gas guide device for generating a circulating flow through the heating chamber, characterized in that the Heating chamber (7) with the exclusion of the gas blower (18, 19) can be closed. 3. Vakuumofen nach Anspruch 2, dadurch gekennzeichnet, daß in der Wandung der Heizkammer (7) eine Öffnung (21) enthalten ist, die durch einen Schieber (25) mit integrierter Wärmedämmschicht verschließbar ist, und daß das Gasgebläse (18, 19) zwischen einer Ruhe-und einer Arbeitsstellung derart hin und her bewegbar gelagert ist, daß der Ventilator (19) in der Ruhestellung außerhalb der Heizkammer (7) liegt, dagegen in der Arbeitsstellung bei geöffnetem Schieber (25) in das Innere der Heizkammer (7) hineinragt.3. Vacuum furnace according to claim 2, characterized in that an opening (21) is contained in the wall of the heating chamber (7), which can be closed by a slide (25) with an integrated thermal insulation layer, and that the gas blower (18, 19) between a rest and a working position is mounted so that it can move back and forth such that the fan (19) in the rest position outside the heating chamber (7) lies, in contrast, in the working position with the slide (25) open, protrudes into the interior of the heating chamber (7). 4. Vakuumofen nach Anspruch 3, dadurch gekennzeichnet, daß auf der Rückseite des Ventilators (19) ein zum Verschließen der Öffnung (21) dienender Stopfen (23) mit integrierter Wärmedämmschicht angebracht ist.4. Vacuum furnace according to claim 3, characterized in that on the back of the fan (19) for closing the opening (21) serving plug (23) is attached with an integrated thermal barrier coating.
EP85104965A 1984-05-08 1985-04-24 Method and vacuum furnace for heat treatment a charge Expired EP0163906B1 (en)

Priority Applications (1)

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AT85104965T ATE37201T1 (en) 1984-05-08 1985-04-24 PROCESS AND VACUUM FURNACE FOR THE HEAT TREATMENT OF A BATCH.

Applications Claiming Priority (2)

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DE19843416902 DE3416902A1 (en) 1984-05-08 1984-05-08 METHOD AND VACUUM OVEN FOR HEAT TREATING A BATCH
DE3416902 1984-05-08

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EP0163906A2 true EP0163906A2 (en) 1985-12-11
EP0163906A3 EP0163906A3 (en) 1986-08-20
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EP (1) EP0163906B1 (en)
AT (1) ATE37201T1 (en)
DE (2) DE3416902A1 (en)

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EP0313889A1 (en) * 1987-10-28 1989-05-03 Degussa Aktiengesellschaft Vacuum furnace for the heat treatment of metallic work-pieces
WO2007048664A1 (en) * 2005-10-27 2007-05-03 Robert Bosch Gmbh Method and installation for the dry transformation of a material structure of semifinished products

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DE3736501C1 (en) * 1987-10-28 1988-06-09 Degussa Process for the heat treatment of metallic workpieces
US5121903A (en) * 1991-03-11 1992-06-16 Vacuum Furnace Systems Corporation Quenching arrangement for a furnace
DE4400326C2 (en) * 1994-01-07 2002-10-31 Ald Vacuum Techn Ag Device for hardening metallic workpieces
DE19615609C2 (en) * 1996-04-19 1998-03-19 Hoffmann Foerdertechnik Gmbh W Hook tackle
US5783001A (en) * 1996-11-14 1998-07-21 Ethicon, Inc. Process for the heat treatment of surgical needles by aging
DE19741837B4 (en) * 1997-09-23 2006-04-27 Robert Bosch Gmbh High temperature furnace and process for heat treatment of materials
US7598477B2 (en) * 2005-02-07 2009-10-06 Guy Smith Vacuum muffle quench furnace
DE102005045783A1 (en) * 2005-09-23 2007-03-29 Sistem Teknik Endustriyel Elektronik Sistemler Sanayi Ve Ticaret Ltd. Sirketi Single-chamber vacuum furnace with hydrogen quenching
US7531769B2 (en) * 2006-06-13 2009-05-12 Guy Smith Carbon fiber composite muffle
DE202008009980U1 (en) * 2008-07-24 2008-10-16 Ipsen International Gmbh Retort oven for the heat treatment of metallic workpieces
US10436512B1 (en) * 2016-07-28 2019-10-08 Thomas Wingens Base component for a thermoprocessing system, a thermoprocessing system, and a thermoprocessing method

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EP0313889A1 (en) * 1987-10-28 1989-05-03 Degussa Aktiengesellschaft Vacuum furnace for the heat treatment of metallic work-pieces
WO2007048664A1 (en) * 2005-10-27 2007-05-03 Robert Bosch Gmbh Method and installation for the dry transformation of a material structure of semifinished products
US8715566B2 (en) 2005-10-27 2014-05-06 Robert Bosch Gmbh Method and installation for the dry transformation of a material structure of semifinished products

Also Published As

Publication number Publication date
EP0163906A3 (en) 1986-08-20
EP0163906B1 (en) 1988-09-14
US4612064A (en) 1986-09-16
ATE37201T1 (en) 1988-09-15
DE3564965D1 (en) 1988-10-20
DE3416902A1 (en) 1985-11-14
US4709904A (en) 1987-12-01

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