DE102012001742A1 - Device, useful for heating, hot-forming and press-hardening of metal sheet workpieces, comprises a first heat station, a second heat station in which the workpieces are heated or held at a specified temperature, and a third heat station - Google Patents

Abstract

The device comprises a first heat station (110) with an inductive heating device, in which metal sheet workpieces are quickly heated without lingering, a second heat station (120) in which the metal sheet workpieces are heated or held at a specified temperature, a third heat station (130), a main lane in which the third heat station is arranged, and a side alley in which the second heat station is arranged. The device is configured to carry out the metal sheet workpieces to be heated, where the main lane and the side alley are connected to an intersection point with a switch (150). The device comprises a first heat station (110) with an inductive heating device, in which metal sheet workpieces are quickly heated without lingering, a second heat station (120) in which the metal sheet workpieces are heated or held at a specified temperature, a third heat station (130), a main lane in which the third heat station is arranged, and a side alley in which the second heat station is arranged. The device is configured to carry out the metal sheet workpieces to be heated, where the main lane and the side alley are connected to an intersection point with a switch (150) for the transition of the metal sheet workpieces of the lanes into other lane. The side alley is formed as dead end, where the second heat station is arranged at an end of the dead end and is designed as stack oven. The switch is arranged at an input of the device. The first heat station is designed as transit station, which passes through in both directions of metal sheet mold parts to be heated. The third heat station is designed as transit station, which passes through in only one direction of the metal sheet mold parts to be heated. The second and third heat stations comprise a heating device that is electrically and/or inductively operated by fuel combustion. The device further comprises transfer devices, which accomplish a transport of the metal sheet workpieces to be warmed within the device, and a control device (160), which accomplishes a fully automated operation of the device.

Description

The invention relates to a device for heating sheet metal workpieces, in particular sheet metal blanks or sheet metal parts, with a view to a subsequent hot forming and in particular press hardening of these sheet metal workpieces.

For heating sheet metal workpieces with a view to a subsequent hot forming or press hardening of these sheet metal workpieces long roller hearth furnaces are usually used, which are traversed by the sheet metal workpieces to be heated. However, such roller hearth furnaces have various disadvantages, such as, for example, a large length and the associated space requirements. Furthermore, such roller hearth furnaces are also controversial from an energetic point of view.

In the DE 10 2009 019 496 A1 a device is proposed which comprises three successive heat stations, which are traversed by the sheet metal workpieces to be heated in succession or successively. The first heat station preferably has an inductive heating device or heating device with which the sheet metal workpieces to be heated can first be heated rapidly (ie in a short period of time) to a high temperature of up to several hundred degrees Celsius. Subsequently, the sheet metal workpieces warmed in this way are fed to the downstream heating stations. The proposed device has various advantages over the roller hearth furnaces. A disadvantage of the proposed device, however, is a lack of flexibility with regard to different heating requirements.

It is therefore an object of the present invention to provide a device of the type mentioned, which does not have the disadvantages associated with the roller hearth furnaces or at least only to a reduced extent and can be handled with the flexible different heating requirements.

This object is achieved by a device according to the invention with the features of claim 1. Preferred developments and refinements emerge from the dependent claims and also from the following explanations.

• – wenigstens eine erste Wärmestation mit wenigstens einer induktiven bzw. induktiv betriebenen Erwärmungseinrichtung, in der die Blechwerkstücke ohne zu verweilen schnell auf eine vorgegebene Temperatur erwärmt werden können;
• – wenigstens eine zweite Wärmestation, in der die Blechwerkstücke verweilen und dabei auf eine vorgegebene Temperatur erwärmt (oder gegebenenfalls auch abgekühlt) oder auf einer bestimmten Temperatur gehalten werden können; und
• – wenigstens eine dritte Wärmestation, in der die Blechwerkstücke verweilen und dabei auf eine vorgegebene Temperatur erwärmt (oder gegebenenfalls auch abgekühlt) oder auf einer bestimmten Temperatur gehalten werden können.

The device according to the invention has a plurality of heat stations. among them

• - At least a first heat station with at least one inductive or inductively operated heating device, in which the sheet metal workpieces can be heated without lingering quickly to a predetermined temperature;
• - At least a second heat station in which the sheet metal workpieces dwell and thereby heated to a predetermined temperature (or optionally also cooled) or can be maintained at a certain temperature; and
• - At least a third heat station in which the sheet metal workpieces dwell and thereby heated to a predetermined temperature (or optionally also cooled) or can be maintained at a certain temperature.

The first heat station allows due to the inductive heating principle, a rapid and targeted heating of the sheet metal workpieces, which is particularly advantageous from an energetic point of view. Preferably, the first heat station is designed as a transit station. The sheet metal pieces to be heated are carried out individually or possibly also to several and without significant residence time through the first heat station and thereby inductively heated, which in particular by Längsfeldinduktion and / or by transverse field induction (see relevant explanations in the DE 10 2009 042 026 A1 ).

The second and the third heat station can be operated in different ways depending on the heating requirement, as explained in more detail below. The second and / or the third heat station preferably comprises at least one electrically operated and / or at least one heating device operated by means of fuel combustion (for example a gas burner). Additionally or alternatively, inductive heating devices may be provided. The second and / or the third heat station are in particular designed such that they can accommodate a plurality of sheet metal workpieces at the same time, wherein these sheet metal workpieces in a common furnace chamber or in separate furnace chambers can be accommodated side by side and / or one above the other. The second heat station is preferably designed as a non-transit station. The third heat station is preferably designed as a transit station.

The device according to the invention is characterized in that it (at least) a main lane or first lane, in which the third heat station is arranged, and (at least) a secondary lane or second lane, for performing or passing through the sheet metal workpieces to be heated the first heat station and the second heat station are arranged, wherein the main lane and the minor lane are connected at a crossing point with at least one switch for the transition of the sheet metal workpieces from one lane to the other lane.

The device according to the invention has at least two lanes. An alley is understood to mean a conveying path or a conveying path along which or along which the sheet metal workpieces to be heated are moved and fed to the individual heating stations and / or passed through them. The lanes are interconnected by means of at least one switch. In other words, the heat stations of the device according to the invention are arranged in different paths, which are connected to at least one switch. A switch allows a defined and uninterrupted transition of the sheet metal workpieces from one lane to the other alley. The switch is designed so that at each transition a sheet metal workpiece or possibly also several sheet metal workpieces are transferred. Such a switch can z. B. be realized by an industrial robot with grippers or similar devices. Depending on the design, such an industrial robot or the like can also be used for loading or equipping one or more heating stations. The assembly can also include the removal.

The individual heat stations of the device according to the invention advantageously allow the heating of the sheet metal workpieces in several different heating and / or temperature maintenance phases, which already from the DE 10 2009 019 496 A1 is known. In the apparatus according to the invention, however, these phases do not have to be passed through rigidly or in a structurally predetermined order. Instead, the sheet metal workpieces may be supplied to the heating stations in a variable order or sequence depending on the given heating requirements. The division of the heat stations on several (ie at least two) lanes and the provision of at least one switch allows flexible handling of very different heating requirements, which also results from the following explanations. Another advantage of the device according to the invention is to be seen in the fact that these with limited space, which is especially in retrofits a common problem encountered in practice, gets along.

The device according to the invention is also particularly suitable for heating sheet metal workpieces with a metallic corrosion protection coating, which is primarily an aluminum-containing anticorrosive coating (eg AlSi) and which in particular provides for a so-called diffusion layer between the sheet material (sheet substrate) during heating ) and the coating material, as explained in more detail below.

The invention will be explained in more detail below in a non-limiting manner with reference to the single figure, wherein in the following explanations, in particular, also addressed to the specified in the dependent claims refinements and embodiments.

1 shows, in a schematic representation, an embodiment of a device according to the invention.

In the 1 shown device 100 is used to heat sheet metal workpieces, which are in particular sheet metal blanks or sheet metal parts, including the automated to be heated sheet metal workpieces by this device 100 be passed. The sheet metal workpieces to be heated are starting from a stacking device 10 the device 100 fed and after heating in the device 100 in the still heated state to a hot forming tool or press hardening tool 20 to hand over. The feeding of the sheet metal workpieces from the stacking device 10 to the device 100 as well as the discharge from the device 100 or the transfer to the tool 20 can be done with any suitable transfer device (eg., An industrial robot or the like).

The dashed line schematically framed device 100 includes a first heat station 110 , a second heat station 120 and a third heat station 130 , The heat stations 110 . 120 and 130 are arranged in different streets A and B. The third heat station 130 is arranged in a main lane A. Hauptgasse A provides a direct (detour-free) connection between the stacking device 10 and the tool 20 dar. The first heat station 110 and the second heat station 120 are arranged in a side street B. The Nebengasse B is designed as a dead end, at the end of the second heat station 120 located. The illustrated T-like arrangement of the lanes A and B is only an example. The device 100 may comprise further heat stations located in the main street A (eg downstream of the third heat station 130 ) or in the minor street B can be arranged. The device 100 has a compact and space-saving design, especially in comparison to a conventional roller hearth furnace.

Hauptgasse A and Nebengasse B are at a crossroads with and over a switch 150 connected, the quasi at the entrance of the device 100 arranged switch 150 the transition of the sheet metal workpieces to be heated from one lane to the other accomplished. The soft 150 can z. B. be realized by an industrial robot or the like. Such an industrial robot or the like could also for Assembly of the first and / or third heat station 110 respectively. 130 be used. The other movements of the sheet metal workpieces to be heated between the heat stations takes place by means of suitable transfer devices (for example roller transport fields, conveyor belts, industrial robots or the like).

The automated operation of the device 100 is from a controller 160 accomplished, with the control connections to the individual heat stations 110 . 120 and 130 to the switch 150 and to the transfer means are not shown in detail. In the device 100 can be located at the same time several sheet metal workpieces.

The first heat station 110 comprises at least one inductive heating device, which may be formed, for example, as Längsfeld- or Querfeldinduktor. Particularly preferably it is provided that the sheet metal workpieces to be heated on a roller transport field or the like (for example, by means of an industrial robot equipped with a suitable gripping device) are guided past this inductor. The first heat station 110 is formed as a transit station, wherein the sheet metal workpieces to be heated in two directions through the first heat station 110 can be passed, as explained in more detail below.

The second heat station 120 and the third heat station 130 comprise at least one electrically operated and / or at least one by means of fuel combustion (eg, a gas burner) operated heating device. The third heat station 130 is also designed as a transit station, wherein the sheet metal workpieces to be heated, the third heat station 130 can go through in one direction only. The second heat station 120 is, however, designed as a non-continuous station. The second heat station is preferred 120 designed as a stack oven or has at least one stack oven.

So that the sheet metal workpieces to be heated from the switch 150 coming to the second heat station 120 At the end of Nebengasse B, these must be the first heat station 110 run through. Also on the way back from the second heat station 120 to the switch 150 this must be the first heat station 110 run through. Ie. the first heat station 110 is formed such that it can be traversed in both directions by the sheet metal moldings to be heated. Optionally, a bypass around the first heat station 110 be provided. Incidentally, such a bypass may also be at the third heat station 130 be provided. The second and the third heat station 120 and 130 Incidentally, each may include one or more furnace devices or the like.

The individual heat stations 110 . 120 and 130 allow a flexible heating of the sheet metal workpieces to be heated in several different heating and / or temperature maintenance phases, wherein the device 100 with only one switch 150 gets along, which can therefore be optimally utilized. Below are various on the device 100 executable heating methods (or modes of operation) that meet different heating requirements, and is not a final exposition of the possibilities given in principle. The temperatures given are sample values and approximate figures.

1.) Heating with prediffusion phase:

At the stacking device 10 For example, a sheet metal workpiece provided with a metallic anticorrosive coating (for example an AlSi coating), which is in particular a sheet metal blank or sheet metal part, is stacked and the device 100 fed. The sheet metal workpiece preferably has room temperature. At the switch 150 the sheet metal workpiece to be heated is diverted into the minor lane B and then passes through the first heat station 110 , wherein it is heated relatively quickly to 600 ° C when passing through without significant residence time.

After passing through the first heat station 110 becomes the sheet metal workpiece of the second heat station 120 at the end of the Nebengasse B, where it is maintained over a longer period or over a longer period of time to about 600 ° C temperature, with a diffusion layer (eg. AlSiFe layer) between the actual sheet material and the metallic coating material is formed. The second heat station 120 thus acts as a diffusion furnace, the energy required to operate this furnace is relatively low, since the recorded sheet metal workpieces do not have to be heated substantially.

The second heat station 120 can accommodate a variety of sheet metal workpieces, which over a longer period of time in the second heat station 120 can stay. The second heat station is preferred 120 designed as a stack oven. By the sheet metal workpiece first in the first heat station 110 inductively heated and then for the purpose of prediffusion of the second heat station 120 supplied, the entire diffusion process can be completed in a short time, so that the device 100 despite its compact size a high Discharge capacity (number of heated sheet metal workpieces per period) has.

After completion of the diffusion process, the sheet metal workpiece from the second heat station 120 removed and to the switch 150 recycled. The sheet metal workpiece in the opposite direction again passes through the first heat station 110 and may be heated to a higher temperature of 720 ° C (below the austenitizing temperature) or 950 ° C (above the austenitizing temperature) while passing through (without appreciable dwell time). Optionally, the sheet metal workpiece can be the first heat station 110 go through without being subjected to a heat treatment. Further, there is also a bypass at the first heat station 110 conceivable, as already explained.

Subsequently, the sheet metal workpiece is at the switch 150 redirected to the main lane A and the third heat station 130 fed. In the third heat station 130 can z. B. a temperature compensation to any of the inductive heating in the first heat station 110 compensate for temperature differences. The third heat station 130 thus acts as a compensation furnace, wherein the compensation temperature may be lower or higher than the temperature in the second heat station 120 and / or as those in the first heat station 110 produced sheet workpiece temperature. The third heat station 130 can accommodate a variety of sheet metal workpieces, which over a shorter or longer period of time in the third heat station 130 can stay. The third heat station is preferred 130 designed as a continuous furnace, wherein the residence time can be varied by changing the flow rate. The third heat station 130 can have several temperature zones. The third heat station 130 can also be designed as a stack oven or at least comprise a stack oven.

During the temperature compensation in the third heat station 130 the sheet metal workpiece can be kept at temperature or optionally also heated (for example, to a temperature above the Austenitisierungstemperatur). In this respect, the third heat station 130 also act as a warming station. Alternatively, the sheet metal workpiece may be the third heat station 130 go through without experiencing a heat treatment, which, for example, by turning off the third heat station 130 can be accomplished. There is also a bypass at the third heat station 130 conceivable, as already explained.

After passing through the third heat station 130 is the now finished sheet metal workpiece from the device 100 discharged and the tool 20 supplied, where this is processed while still heated.

2.) Heating without pre-diffusion phase:

In contrast to the procedure explained above (with a prediffusion phase), the sheet metal workpiece to be heated, after it has been heated to a temperature of 600 ° C. in or at the first heat station, does not reach the second heat station 120 but over the switch 150 almost directly to the third heat station 130 fed.

This procedure is suitable for. B. for the rapid heating of sheet metal workpieces, which is in particular sheet metal workpieces with a metallic corrosion protection coating, which already has a diffusion layer in the delivery state, so that a prediffusion phase is not required.

3.) Heating only with the third heat station:

If no high heating requirements are imposed and / or if only low output is needed, heating may only occur in the third heat station 130 carried out, including the sheet metal workpieces to be heated only along the main lane A through the device 100 be passed. The third heat station 130 acts as a kind of conventional heating furnace. The first heat station 110 and the second heat station 120 as well as the switch 150 can stay off.

LIST OF REFERENCE NUMBERS

10

stacking

20

Tool

100

contraption

110

first heat station

120 '

second heat station

130

third heat station

150

switch

160

control device

A

Main street (first street)

B

Nebengasse (second lane)

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009019496 A1 [0003, 0011]
• DE 102009042026 A1 [0007]

Claims (10)

Contraption ( 100 ) for heating sheet metal workpieces for subsequent hot forming and in particular press hardening, comprising: - at least one first heating station ( 110 ) with at least one inductive heating device, in which the sheet metal workpieces can be heated quickly without lingering; At least one second heat station ( 120 ), in which the sheet metal workpieces can stay and thereby be heated or kept at a certain temperature; and - at least one third heat station ( 130 ), in which the sheet metal workpieces can stay and thereby be heated or kept at a certain temperature; characterized in that this device ( 100 ) for carrying out the sheet metal workpieces to be heated a main lane (A), in which the third heat station ( 130 ) and a secondary lane (B) in which the first heat station ( 110 ) and the second heat station ( 120 ), wherein the main lane (A) and the secondary lane (B) at a crossing point with a switch ( 150 ) for the transition of the sheet metal workpieces from one lane (A; B) to the other lane (B; A). Contraption ( 100 ) according to claim 1, characterized in that the secondary lane (B) is formed as a dead end, wherein the second heat station ( 120 ) is arranged at the end of this dead end. Contraption ( 100 ) according to claim 1 or 2, characterized in that the second, heat station ( 120 ) is designed as a stack oven. Contraption ( 100 ) according to one of the preceding claims, characterized in that the switch ( 150 ) at the entrance of the device ( 100 ) is arranged. Contraption ( 100 ) according to one of the preceding claims, characterized in that the first heat station ( 110 ) is formed as a transit station, which can be traversed in particular in both directions of the sheet metal moldings to be heated. Contraption ( 100 ) according to one of the preceding claims, characterized in that the third heat station ( 130 ) is designed as a transit station, which can be traversed in particular in only one direction of the sheet metal moldings to be heated. Contraption ( 100 ) according to one of the preceding claims, characterized in that the second heat station ( 120 ) has at least one electrically operated and / or at least one operated by means of fuel combustion and / or at least one inductively operated heating device. Contraption ( 100 ) according to one of the preceding claims, characterized in that the third heat station ( 130 ) has at least one electrically operated and / or at least one operated by means of fuel combustion and / or at least one inductively operated heating device. Contraption ( 100 ) according to one of the preceding claims, characterized in that it comprises at least one and preferably a plurality of transfer devices which facilitate the transport of the sheet metal workpieces to be heated within the device ( 100 ) accomplish. Contraption ( 100 ) according to one of the preceding claims, characterized in that it comprises a control device ( 160 ), which enables fully automated operation of the device ( 100 ) accomplished.

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