EP1555330A2 - Installation and process for the transport of metallic workpieces and installation for the heat treatment of metallic workpieces - Google Patents

Abstract

The arrangement has a heat-insulated transport chamber (10) to hold work pieces (20). The chamber is moved horizontally and designed to be vacuum-tight, and evacuated of air to create vacuum to protect work pieces from environmental influences. The chamber has a heating unit for heating a treatment chamber. The transport chamber has removable thermal insulation made of steel. A vacuum pump evacuates the air from the transport chamber. Independent claims are also included for the following: (a) a system for heat treating metallic work pieces; and (b) a method of transporting metallic work pieces during a heat treatment process.

Description

The invention relates to a device for transporting metallic Workpieces, in particular during a heat treatment, with a heat-insulated transport chamber for receiving the workpieces, means for loading and unloading the workpieces and a transport chamber is provided moving landing gear. The invention further relates to a plant for heat treatment of metallic workpieces, at least two treatment chambers in which the workpieces heat treatable are, has. In addition, the invention has a method for Transporting metallic workpieces during a heat treatment to do, in which the workpieces in a heat-insulated transport chamber between at least two treatment chambers in which the workpieces are heat-treatable, transported.

For generating defined workpiece properties, such as a high Hardness or special wear resistance, become metallic workpieces usually a thermal or thermochemical heat treatment subjected. The result of the heat treatment is a different one Material structure that gives the workpieces the required properties gives. Of particular influence on the treatment outcome is in addition the general process parameters pressure, temperature and Treatment time also the atmosphere in which the heat treatment is carried out. A number of procedures are known in the art where the workpieces are exposed to different atmospheres, to achieve the desired treatment result. The workpieces be successively several treatment chambers one Heat treatment plant supplied. The individual treatment chambers are for this purpose usually by a transfer lock, which the Protects workpieces from environmental influences during transport the treatment achieved so far in a disadvantageous manner would interfere with each other. The transfer lock is either acted upon by a protective gas atmosphere, such as For example, from DE-A-43 16 841 known, or evacuated, as in FR-A-2 771 754 is proposed.

Such transfer locks are associated with the disadvantage that they have a variable design of the process sequence of the heat treatment plant at most to a limited extent. In addition, the expansion of the Heat treatment plant even with a modular designed construction, as known from FR-A-2 771 754, not without one to realize a relatively high cost. In economic terms is also very unsatisfactory, that is maintenance individual treatment chambers and in particular on the trolley in the transfer lock only at the acceptance of the temporary closure of the complete heat treatment plant.

From US-A-5 567 381 a heat treatment plant is also known, a vacuum oven, a lock and a mobile transport chamber having. The transport chamber is via the lock to the vacuum furnace coupled. The heat insulated to the outside and with a hermetic closing door provided transport chamber also has a Heating device for heating the workpieces and a conveyor for loading and unloading the workpieces. To put in the vacuum oven a certain temperature heated workpieces in another Treatment chamber, such as a quenching chamber, transfer, is the Transport chamber coupled to the lock and preheated. Subsequently Both the lock and the transport chamber with an inert gas up to a pressure greater than the ambient pressure flooded to prevent air from entering the lock or the transport chamber from the outside arrives. The workpieces in the vacuum oven are then on cooled in the transport chamber temperature, and the Vacuum furnace is also flooded with inert gas. After in a vacuum oven and in the lock or transport chamber the same Pressure level is reached, the door of the vacuum oven is opened and the Workpieces by means of the conveyor of the transport chamber in this loaded into it.

With the transport chamber described above, it is therefore possible Workpieces in the heated state from a treatment chamber to transport them while keeping them in an atmosphere of inert gas to suspend, which prevents unwanted oxidation of the workpieces. Although the heat treatment plant according to US-A-5 567 381 thus a offers greater flexibility than those discussed above Heat treatment plants with a stationary transfer lock, points they have the disadvantage that when coupling the transport chamber to the Vacuum furnace both the transport chamber and the lock and the Vacuum oven be flooded with the inert gas. Apart from that, this a not inconsiderable expense for the provision of the Inert gas requires, the inert gas proves to be a hindrance to the Workpieces also during transport to another Treatment chamber to undergo a continuous heat treatment. Because with the inevitable flooding of the vacuum furnace with inert gas Concomitant change in the furnace atmosphere is not only the Completion of the taking place in the vacuum furnace process step of Heat treatment ahead, but inevitably with a Cooling of the workpieces connected, provided the inert gas is not preheated. The latter contributes in a particularly disadvantageous way a heat treatment in the high temperature range noticeable, in which usually no significant temperature fluctuations are allowed.

Finally, from FR-A-2 782 156 a device for Transporting metallic workpieces known with a Transport chamber for receiving the workpieces, means for loading and Unloading the workpieces and a transport chamber moving Suspension is provided, wherein the transport chamber can be moved horizontally, formed vacuum-tight and on a the workpieces before Environmental influences protective vacuum is evacuable as well as a horizontal batch loading and unloading device contains. At this Prior art device, it is disadvantageous that the transport chamber not formed thermally insulated. Thus, the temperature within the Transport chamber of the known from FR-A-2,782,156 device not be kept constant, so that it adversely unwanted temperature drops within the transport chamber can come. Thus, the previously known from FR-A-2,782,156 Device not for the transportation of during a heat treatment suitable before Termperaturschwankungen to be protected workpieces.

The invention has for its object to provide an apparatus and method for transporting metallic workpieces and a plant for heat treatment of these workpieces, which allow a comparatively flexible and efficient way transport of the workpieces between a plurality of treatment chambers during a heat treatment.

To solve this problem, a device for transporting metallic workpieces, in particular during a heat treatment, with a heat-insulated transport chamber for receiving the workpieces, means for loading and unloading of the workpieces and a transport chamber moving chassis, the transport chamber horizontally movable, vacuum-tight formed and on the workpieces from environmental influences protective vacuum can be evacuated and a horizontal batch loading and unloading device, wherein the transport chamber is heated, and wherein the transport chamber is provided with a replaceable thermal insulation.

Such a trained device offers in comparison to the in State of the art stationary transfer locks a flexible Transport of workpieces during a heat treatment. That's the way to go about individual treatment chambers of a heat treatment plant for Maintenance or repair work from the process cycle exclude, without the other treatment chambers thereby in Be affected. Also the extension of an existing one Heat treatment plant to additional treatment chambers is with the inventive device without much effort possible.

Moreover, such a device makes the knowledge its own, that a much more efficient process can then be achieved, if instead of flooding with inert gas a vacuum in the Transport chamber is generated to unwanted the workpieces Environmental influences, such as by the supply of oxygen conditional oxidation, protect. Unlike the mobile Transport chamber according to US-A-5 567 381 it is in the device according to the invention thus possible, the heat treatment during the transport of the workpieces to another Continue treatment chamber in the transport chamber, without that a noticeable temperature change occurs. In addition to this time-saving, economical in terms of time Therefore, the device according to the invention also characterized by the fact that they is particularly suitable for heat treatment processes used in the High temperature range take place.

It is particularly advantageous if the device is equipped with a vacuum pump is provided for evacuating the transport chamber. This offers the advantage that the device with respect to the evacuation of the transport chamber self-sufficient and thus independent of the respective type of Treatment chambers is. It can therefore, for example, both Dock vacuum or atmospheric furnaces as well as on cooling chambers. Furthermore, the provision of a vacuum pump allows the Transport chamber also be evacuated during transport can. This comes into play, for example, when loading the Workpieces from a treatment chamber in the transport chamber in the treatment chamber located atmosphere in the transport chamber is allowed to expand to the heat treatment in this atmosphere during transport until just before reaching the next one Continuing treatment chamber.

Another advantage is to heat the transport chamber. Although the Transport chamber already due to their thermal insulation one Temperature drop of the workpieces counteracts, resulting in short Transport routes is usually sufficient, but it can in cases of Heat treatment with high temperatures may be required Workpieces by an additional heat input on the desired Keep temperature. As very useful in this context turned out, the transport chamber with a replaceable to provide thermal insulation. Such isolation can be for Replace repair and maintenance without hindrance. she offers Furthermore, the advantage that due to their low heat storage, the Temperature of the transport chamber changed within a few minutes, the means the different temperatures of several treatment chambers can be adapted. According to a feature of the invention, the Insulation made of steel, for example a chromium-nickel steel.

In a particularly beneficial development of the invention Device is the transport chamber with a hermetically closing Loading door actuated by a drive to one automatic docking of the transport chamber to a treatment chamber sure. In terms of one in operational practice always recurrent accident, it may also be advantageous to the Transport chamber additionally with a hermetically closing mounting door to provide. For example, by means of an external Hubladegeräts the Transport chamber thus regardless of the circumstances may not be free accessible loading door to be unloaded through the mounting door.

An extremely advantageous embodiment of the device according to the invention is also given if transport chamber and suspension relatively are movable relative to each other. Because this makes it easy possible, the trajectory to be traveled by the device of the arrangement of largely decouple individual treatment chambers and thus the to take the best possible account of the respective operational circumstances. When Particularly suitable in this context has been shown Transport chamber horizontally pivotable or horizontal and / or vertical direction to be arranged in a straight line on the chassis. The latter variant is used, for example, if several Treatment chambers are arranged vertically one above the other.

In terms of effortless docking of the transport chamber Treatment chambers whose loading sides differ in space Alternatively, or additionally, it may be useful to have the Suspension in such a way that it turns the device on the Job allows. So it is about two-sided one Heat treatment line with respect to their loading side vis-à-vis arranged treatment chambers sufficient in this case, the Transport chamber in an economically favorable manner only with a loading door to provide. Advantageously, the chassis is depending on the operational Need rail-bound or sunk into the ground Induction loops freely steerable. For convenient loading of the workpieces from a treatment chamber in the transport chamber or the other way around, it has also proved useful to and unloading the workpieces have a loading fork, which is horizontal and is vertically movable.

To achieve the above object is proposed in a system for heat treatment of metallic workpieces with the features mentioned that a device according to one of claims 1 to 9 can be coupled by means of an evacuable lock to the treatment chamber.

Such a heat treatment plant makes the related with the device described above for transporting metallic Benefit from workpieces. By providing the lock It is ensured that the workpieces from environmental influences protected between a treatment chamber and the transport chamber can be shipped. The inventive Heat treatment plant is characterized by great flexibility in Regard to the transport of workpieces between the individual Treatment chambers, which also results in a relatively high Throughput and thus efficient in economic terms Achieve process management.

To be as compact and relatively lightweight Designing the transport chamber, it is useful to the Lock to arrange stationary at the treatment chamber. This has to Result that a lock is to be provided on each treatment chamber. In general, however, the lock can also be an integrated part of Transport chamber or even be mobile. The latter version is Although associated with a higher design effort, but offers about when the heat treatment plant over a large number at treatment chambers, each with long residence times of the workpieces has, so that a mobile lock in time unproblematic can be used for several treatment chambers.

It is also expedient if the lock is separately evacuated, so that regardless of the type of treatment chamber, for example Vacuum oven or atmospheric oven, is to operate. It is also on this Way possible, the lock already during the transport of Transport chamber to the appropriate treatment chamber evacuate to ensure the fastest possible procedure. ever However, after application, it is also conceivable that the lock through a arranged on the transport chamber vacuum pump is evacuated. In a particularly advantageous embodiment of the system according to the invention the lock has a drive through which the loading door of the Transport chamber is actuated. This contributes to a special lightweight design of the transport chamber and thus to relatively low cost of conveying the workpieces between the individual treatment chambers. In terms of one The greatest possible variability in the design of the heat treatment is the Treatment chamber suitably a vacuum oven, a Atmosphere oven or a cooling chamber.

In procedural terms, the solution to the above problem in a method having the features mentioned is characterized in that the vacuum-tight transport chamber is evacuated to a workpieces from environmental influences protective vacuum and the workpieces are transported in this vacuum from one treatment chamber to the next.

The transport of the workpieces in one to a given vacuum evacuated transport chamber has been mainly for the transport of heated a relatively high temperature of, for example, 1000 ° C Workpieces proved to be extremely advantageous. Unlike the im State of the art known transport of the workpieces in one Atmosphere of inert gas can be in this way namely often avoid unwanted temperature drop. In further education of the The method according to the invention is further proposed, the Transport chamber by means of a lock to the respective Coupling treatment chamber to those described above Benefits to use. Finally, it is proposed to separate the lock to evacuate to a speedy coupling of the transport chamber sure.

Fig. 1a

eine schematische Seitenansicht einer Vorrichtung zum Transportieren metallischer Werkstücke;

Fig. 1b

einen Schnitt gemäß der Linie Ib-Ib in Fig. 1 und

Fig. 2

eine schematische Darstellung einer Anlage zur Wärmebehandlung metallischer Werkstücke mit einer der Vorrichtung nach den Fig. 1a und 1b ähnlichen Transportvorrichtung.

Details and further advantages of the subject matter of the present invention will become apparent from the following description of a preferred embodiment. In the accompanying drawings show in detail:

Fig. 1a

a schematic side view of an apparatus for transporting metallic workpieces;

Fig. 1b

a section along the line Ib-Ib in Fig. 1 and

Fig. 2

a schematic representation of a plant for heat treatment of metallic workpieces with a device of the Fig. 1a and 1b similar transport device.

The device shown in Fig. 1a for transporting metallic Workpieces 20 has a heat-insulated and vacuum-tight to the outside trained, cylindrical transport chamber 10 for receiving the a batch of assembled workpieces 20 and a the Transport chamber 10 moving chassis 30. The device is also with means 40 for loading and unloading of the workpieces 20 provided, which have a horizontally movable pawl 41. Through a electromechanical drive can be the latch 41 by means of a forward and move backward pressure chain 43 in the horizontal direction, the Guiding the empty strand in a vertically arranged receptacle 42 is made. In this way, it is ensured that all Startbeziehungsweise Braking in terms of a reliable Dispatch of the workpieces 20 of the transport chamber 10 in a Run treatment chamber 50 or vice versa soft.

As can be seen mainly in Fig. 1b, the transport chamber 10th a flange 11 for a vacuum pump, not shown. By means of On the landing gear 30 mounted vacuum pump, it is possible to use the interior the transport chamber 10 to a final pressure of about 0.1 mbar (= 10 Pa) evacuate and at a leak rate of about 0.003 mbar l / s on this To maintain pressure level. Consequently, it is ensured that in the Transport chamber 10 located, heat treated workpieces 20 before Environmental influences, such as an undesirable oxidation inducing oxygen supply, are protected.

To a noticeable temperature drop of about before in a Treatment chamber 50 to avoid heated workpieces 20 is the Transport chamber 10 with a replaceable thermal insulation 12th made of, for example, chromium-nickel steel and has in addition to a current feedthrough 13 connected heating elements 14. The Heating elements 14 allow heating of the empty transport chamber 10th to approx. 1000 ° C in the shortest possible time at a control temperature of approx. ± 5 ° C.

On its front side, the transport chamber 10 is hermetically sealed closing loading door 15 provided by a in the present case hydraulically, depending on the application but also electrically or pneumatically actuatable drive 16 can be raised in the vertical direction. When opening or closing the loading door 15 moves in one double-walled portal 17, on which the transport chamber 10th remote side coupling means 18 are arranged. With the help of Coupling means 18, the transport chamber 10 can be vacuum-tight to a only hint lock port 60 dock.

The provided with wheels 31 chassis 30 of the device is by a controlled by an inverter and thus soft starting or braking gear motor driven. The one Positioning accuracy of approx. ± 1 mm permitting travel speed the free-wheeling in all directions and rotating on the spot Chassis 30 is only between 0.01 m / s and 0.03 m / s, so that additional protective measures, such as a grid arrangement, dispensable are. At the front and rear end of the chassis 30 are However, safety devices provided to hitting a Obstacle to trigger an emergency stop. On the chassis 30 are also Rails 32 are arranged, through which the transport chamber 10 relative to The chassis 30 can be moved on a distance of about 200 mm. The Transport chamber 10 is thereby not shown Hydraulic cylinder moves.

With the device described above for transporting metallic Workpieces 20 can be batches with a dimension of 600 mm x 900 mm x 600 mm and a maximum weight of 600 kg - but also Batches of 900 mm x 1200 mm x 900 mm and 1000 kg and even more larger as well as smaller - with temperatures of up to 1100 ° C flexible and efficiently between multiple treatment chambers 50 of a plant for Heat treatment of metallic workpieces 20 transport. In the Representation of FIG. 2, such a system is shown. The two-sided one the device described above with slight modifications corresponding transport device 70 vis-a-vis set up Treatment chambers 50 are in this case as vacuum preheating chamber 50a, Vacuum carburizing chambers 50b, diffusion chambers 50c and Gas quenching chamber 50d - or oil or Salt bath quenching chamber - formed.

To the via a conveyor belt or a roller conveyor 51 in the vacuum preheating chamber 50a introduced at the beginning, untreated workpieces 20 corresponding to the respective heat treatment Transporting treatment chambers 50, the transport chamber 10th the transport device 70 over the stationary in front of each Treatment chamber 50 arranged lock 60 to the vacuum preheating chamber 50a docked. For loading the transport chamber 10th with the workpieces 20, the lock 60 and the transport chamber 10th evacuated. Then, the doors of the vacuum preheat chamber 50a and the lock 60 and the loading door 15 of the transport chamber 10 is opened and the workpieces 20 by means of the loading fork 41 in the transport chamber 10th shipped. After the loading door 15 is closed again, the Transport chamber 10 to one of the vacuum carburizing 50b transported. The thermal insulation 13 and the heating elements 14 provide while sure that the workpieces 20 experience no loss of temperature. Upon reaching the position of the corresponding carburizing chamber 50b opens one of the loading door 15 opposite the second door on Rails 71 linearly movable transport device 70, and the Workpieces 20 are over the standing on this treatment chamber 50 Lock 60 by means of the loading fork 41 in the carburizing 50b postponed.

During further transport of the workpieces 20 in about one of Diffusion chambers 50c or the gas quenching chamber 50d repeated the procedure described above in a corresponding manner. The respectively separately evacuated designed locks 60 contribute to the Workpieces 20 without much loss of time between Treatment chambers 50 can be transported, which, such as the Carburizing chambers 50b and the diffusion chambers 50c, different Atmosphere, while ensuring that the Workpieces 20 in which they protect against environmental influences vacuum be transported in the interior of the transport chamber 10. After all leave the workpieces 20, the gas quenching chamber 50d over Conveyor belt 52, the workpieces 20 depending on the type of heat treatment still to a tempering furnace 53 and a subsequent to this Cooling tunnel 54 promotes.

The above-described, only one loading door 15 having and thus structurally simpler to design device for Transporting metallic workpieces 20 could also be in the frame use the last discussed heat treatment plant. Reason for this is that the chassis 30 of this device is designed such that the Transport chamber 10 is rotatable on the spot, causing the can be easily docked opposite treatment chambers 50.

LIST OF REFERENCE NUMBERS

10

transport chamber

11

flange

12

insulation

13

power supply

14

heating element

15

loading door

16

drive

17

portal

18

coupling means

20

workpieces

30

landing gear

31

wheel

32

rail

40

Means for loading and unloading

41

pawl

42

admission

43

pressure chain

50

treatment chamber

50a

Vacuum preheating

50b

Vacuum carburizing

50c

diffusion chamber

50d

Gas quenching chamber

51

Conveyor belt / roller track

52

Conveyor belt / roller track

53

tempering furnace

54

cooling tunnel

60

lock

70

transport device

71

rail

Claims (17)

Device for transporting metal workpieces (20), especially during a heat treatment, with a heat-insulated transport chamber (10) for receiving the workpieces (20), means (40) for loading and unloading the workpieces (20) and a transporting chamber (10) moving chassis (30), wherein the transport chamber (10) horizontally movable, vacuum-tight trained and on a the workpieces (20) from environmental influences protective vacuum is evacuable as well as a horizontal Batch loading and unloading device contains, wherein the Transport chamber (10) is heated, and wherein the transport chamber (10) provided with a replaceable thermal insulation (12) is. Apparatus according to claim 1, characterized by a vacuum pump for evacuating the transport chamber (10). Apparatus according to claim 1 or 2, characterized in that the replaceable thermal insulation (12) is made of steel. Device according to one of claims 1 to 3, characterized in that the transport chamber (10) is provided with a hermetically closing loading door (15) which can be actuated by a drive (16). Apparatus according to claim 4, characterized in that the transport chamber (10) is provided with a hermetically closing mounting door. Device according to one of claims 1 to 5, characterized in that the transport chamber (10) and chassis (30) are movable relative to each other. Apparatus according to claim 6, characterized in that the transport chamber (10) is arranged horizontally pivotable or in a horizontal and / or vertical direction linearly movable on the chassis (30). Device according to one of claims 1 to 7, characterized in that the chassis (30) is designed to be rotatable on the spot. Device according to one of claims 1 to 8, characterized in that the chassis (30) is rail-bound or by embedded in the ground induction loops or freely steerable. Plant for the heat treatment of metallic workpieces (20) with at least two treatment chambers (50) for horizontal batch pick-up, in which the workpieces (20) are heat-treatable,
characterized in that a device according to one of claims 1 to 10 by means of an evacuable lock (60) to the treatment chamber (50) can be coupled. Installation according to claim 10, characterized in that the lock (60) is arranged stationarily on the treatment chamber (50). Installation according to claim 10 or 11, characterized in that the lock (60) can be evacuated separately. Installation according to one of claims 10 to 12, characterized in that the lock (60) has a drive, through which the loading door (15) of the transport chamber (10) can be actuated. Plant according to one of claims 10 to 13, characterized in that the treatment chamber (50) is a vacuum furnace, an atmospheric furnace or a cooling chamber. Method for transporting metallic workpieces (20) during a heat treatment in which the workpieces (20) are transported in a heat-insulated, horizontally movable transport chamber (10) between at least two horizontally loadable treatment chambers (50) in which the workpieces (20) are heat-treatable become,
characterized in that the vacuum-tight formed transport chamber (10) is evacuated to the workpieces (20) from environmental influences protective vacuum and the workpieces (20) are transported in this vacuum from one treatment chamber (50) to the next and kept at treatment temperature without significant temperature decrease. A method according to claim 15, characterized in that the transport chamber (10) by means of a lock (60) is coupled to the respective treatment chamber (50). A method according to claim 16, characterized in that the lock (60) is evacuated separately.

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