WO2005021177A1 - Method for shaping metal sheets - Google Patents

Abstract

Disclosed is a method for shaping metal sheets, especially for warm working or hot working blanks (1, 2, 3, 4), in a shaping tool (8). According to said method, one or several reinforcement blanks (2, 3, 4) are applied to a basic blank (1) so as to partially reinforce the same, the basic blank (1) and the at least one reinforcement blank (2, 3, 4) are fixed on top of each other and/or are aligned relative to each other by means of appropriate means, and the basic blank (1) and the at least one reinforcement blank (2, 3, 4) are jointly shaped. The basic blank (1) and the at least one reinforcement blank (2, 3, 4) are separated following the shaping process, are provided with at least one connecting layer (11), and are joined back together, and/or a surface coating (20, 30, 40) is applied to the at least one reinforcement blank (2, 3, 4) as a connecting layer or so as to form a connecting layer, and/or the basic blank (1) and the at least one reinforcement blank (2, 3, 4) are provided with a connecting layer and are jointly shaped while warm.

Description

 Process for forming sheet metal

The invention relates to a method for forming sheet metal, in particular for warm or hot forming of blanks, in a forming tool, one or more reinforcement boards being applied to a base plate for partial reinforcement and the base plate and the at least one reinforcement plate being formed together.

Such methods are known in the prior art, in particular in the production of molded parts for vehicles. In the vehicle sector in particular there is a fundamental requirement to design parts that are as lightweight as possible in terms of weight. This can reduce the vehicle's fuel consumption and significantly improve its manageability and driving properties. At the same time, however, good stability of the vehicle parts is to be ensured, especially crash stability. For the molded parts, such as vehicle spars, which are partially highly stressed in such a crash, it is known to provide these locations which are subject to greater stress locally. Such local reinforcement can be achieved by enlarging the cross section, for example by doubling up metal sheets. In the past, the base plate and the reinforcement plate were each deep-drawn on their own and then joined together to form a complete structural part. Since, in the rarest of cases, a precise fit can be achieved between the shaped reinforcing plate to be added and the separately shaped base plate, gaps usually form at least in the edge area when such shaped parts are joined together. Moisture can penetrate into it and lead to corrosion. However, this is particularly to be avoided since the doubling is provided precisely where the sheet metal used is reinforced is required. Corrosion, however, leads to a weakening of such an area.

DE 4307563 C2 therefore suggests, in the area of deep-drawing of sheet metal, that the base sheet and the reinforcing sheet are deep-drawn or stamped together. The reinforcing sheet or sheets are attached to the base sheet before the common deep-drawing or die-cutting and after the deep-drawing or die-cutting are non-detachably connected to the base sheet. This publication also discloses the provision of corrosion protection measures in the area of the sheets lying one on top of the other. For this purpose, the provision of coated or galvanized steel sheets or the interposition of a plastic or metal foil or an adhesive layer (see also DE 10120121 AI) is mentioned.

Since deep drawing as a Kaitverformvorgang the tools when double the sheet metal to be deeply stressed, it is proposed in DE 10049660 AI, a patched composite sheet from a base plate and reinforcing plate (s) in the warm state at 800 - 850 ° C in a desired shape and on the Cool the forming tool in a defined manner while mechanically maintaining the forming state. To connect the base plate and the reinforcement plates, the contact surface of at least one of the plates is provided with a hard solder over the entire area before they are applied to the base plate. After the solder application and before heating, a connection point is placed between the reinforcement plate and the base plate in order to ensure that the plates are clearly positioned against one another. Before the joint forming, the patched composite sheet is heated to a temperature above the forming temperature of the material of the sheet, formed into the desired shape in the warm state and then held in the closed state with mechanical fixation in the forming state Forming tool and / or fixing and trimming tool cooled in a defined manner.

A method similar to DE 10049660 AI also discloses DE 10136433 AI. According to this document, a local high reinforcement and increase in rigidity with low additional weight is achieved in a sandwich structure made of base plate and reinforcing plate by inserting a molded body made of glass or a glass mat between these two plates. Forming is then carried out in accordance with DE 10049660 AI by hot forming of the entire patched composite sheet, initially heating again to temperatures above the forming temperature of the materials of the sheet, then the composite is placed in a forming tool in the hot state, shaped into the desired shape and mechanically Fixation of the desired forming condition is cooled. In order to prevent the doughy glass from escaping from the gap between the base plate and the reinforcement plate, the edge of the reinforcement plate is connected to the base plate around the glass intermediate element, thereby creating a cavity for the glass intermediate element.

In the processes for forming sheet metal discussed above, either no hot forming and thus a high and partially different load on the deep-drawing tool is provided, or hot forming, which, however, due to the use of an area-wide application of a hard solder, proves to be tedious when it is applied in paste form , exact dosing and positioning is required if it is sprayed on, sprinkled on or placed in the form of chips or applied in the form of a soldering foil, which also requires a precise cut beforehand. The provision of a pocket or a cavity for a glass Intermediate element or a glass mat has the disadvantage that on the one hand such a cavity has to be created, on the other hand the glass mat, if it does not have the dimensions of the reinforcing plate, allows moisture to penetrate at its edges and thus corrosion of the plates used.

The present invention is based on the object of providing a method for hot-forming sheet metal or blanks which does not have the disadvantages mentioned above and which enables the production of molded parts in lightweight construction with reinforcement provided for a partially higher load, the compared to the above prior art Technology an even more effective corrosion protection in connection with a secure connection of the main board and the reinforcing board (s) should be possible.

The object is achieved for a method according to the preamble of claim 1 in that the base board and the at least one reinforcement board are fixed to one another and / or aligned with one another by suitable means and the base board and the at least one reinforcement board are separated after the forming, with at least one connecting layer provided and reassembled. The object is also achieved by a structural part which is produced by a method according to the invention. Further developments of the invention are defined in the dependent claims.

This creates a method for warm or hot forming of sheet metal, in particular blanks, in which the advantages of a common U-forming of blanks to be joined and of warm or hot forming are combined with those of optimal sealing and optimal joining of the shaped blanks. Due to the Using a common half-hot or hot forming of the base plate and reinforcing plate (s), a very good manufacturing accuracy and avoidance of gaps between the formed plates can be achieved in combination with the advantage of any desired degree of forming due to the use of a half-warm or hot forming in contrast for example to cold forming such as deep drawing. As a result, the press tools used in particular can be protected, even when using almost any material thickness of blanks and their combination with one another. Lower temperatures are used for semi-hot forming than for hot forming, which means that there is generally no material hardening. However, high-strength materials that already have high-strength properties can be used, for example. In this case, it is only necessary to increase the temperature in areas which facilitate forming, in particular to temperatures below 850 ° C., preferably between 500 and 730 ° C., particularly preferably between 500 and 700 ° C., in particular around 650 ° C.

By separating the shaped blanks according to the invention after warm or hot forming, it is possible to use a suitable one

Insert the connection layer between the molded parts and thus ensure an optimal connection and sealing of the molded base board and molded or molded reinforcement board (s). Since that

Occasionally, preferably after the forming process, the application of a hot glue has also proven to be very advantageous, for example during the cooling phase of the formed

Blanks within the forming tool. It lies on the part of the molded

Boards then the temperatures suitable for hot gluing. Likewise, however, is the separation of the molded boards after they have cooled and the subsequent application of the at least one connecting layer possible. In this case, the choice of connection layer is arbitrary. For example, a sealing and moisture-repellent foam adhesive layer, material film, in particular pressure-sensitive adhesive film, mat, in particular adhesive fiber composite mat, etc. can also be used.

The connecting layer is preferably formed from a multicomponent adhesive, the components of which are applied to the surface of the motherboard and the at least one reinforcing board or the surfaces of the reinforcing boards. As a result, the surfaces of the boards are advantageously connected only after they have been firmly joined together. In this case, the presence of heat usually proves to be advantageous for rapid curing, which is why the surfaces of the boards to be joined together can be provided with the multi-component adhesive and bonded to one another before the boards have completely cooled.

In the case of a simpler, easily separable shaping of the blanks of the molded part to be created, it has been found that the formed ones are separated

Boards as advantageous. For more complex shapes, especially for

Providing undercuts, which make subsequent separation of the shaped blanks difficult, on the other hand, it proves to be advantageous not to have to separate the shaped blanks again. In order to make this possible, a

Surface coating can be applied to form a or as a connecting layer. The surface coating is preferably applied to the at least one before the warm or hot forming process

Reinforcement board applied, the surface coating melts during the forming and a connection between the Main board and the at least one reinforcement board forms. This advantageously makes it possible for the boards to be connected to one another already during the forming. Coating, in particular, the reinforcement board (s) enables an optimal and uniform connection with the base board up to the edge of the reinforcement board and, if necessary, from individual reinforcement boards to one another. In this way, a full-surface connection of the boards up to the edge region of the reinforcing board (s) can be achieved even with very complex shapes. An additional application of a bead of sealant in the edge region of the at least one reinforcing board is therefore no longer necessary, but can, however, be provided if this is desired.

The connecting layer in the form of a surface coating of the at least one reinforcing board can also prove to be advantageous as a surface coating which is applied to the isolated shaped boards after the warm or hot forming. In this case, any adhesive and / or sealant, for example an adhesive such as a silicone, in particular epoxy resin adhesive, polyurethane adhesive, hot melt adhesive, PUR dispersion adhesive, etc., can be used as the coating material. The coating can be done, for example, by rolling up, dipping, printing, gumming, etc.

The connection layer can completely cover the surface of the reinforcement board (s). However, it can also be embodied as a pattern or mask on the surface of the at least one reinforcing board and / or the base board, in particular surrounding the edge region of the reinforcing board essentially without gaps. Sometimes it is not absolutely necessary to cover the entire surface of the To provide the reinforcement board (s) with the respective connection layer, since a connection of the shaped boards is already supported by their shape and sealing is only useful in the edge region of the reinforcement board (s) for corrosion protection. When selecting the pattern or mask, this is advantageously matched to the forces acting on the finished molded part during operation, so that unwanted detachment of the blanks from one another can be avoided.

The connecting layer preferably consists of a glass material and / or adhesive applied as a coating on the base plate and / or the at least one reinforcement plate, which melts during the forming process and forms a firm connection between the base plate and the reinforcement plate (s) during cooling. The hot-working process melts the glass material, which is applied particularly thinly, and forms an adhesive coating on the reinforcing sheet (s). Similar to an enamel layer, a firm connection between the adjacent board surfaces can occur when cooling. Corrosion protection is made possible, as is a firm connection of the molded boards. In contrast to the provision of glass intermediate elements in cavities between a base plate and a reinforcing plate, as disclosed in DE 10136433 AI, it is possible to provide a very thin connecting layer that is much more resilient than the thick glass intermediate layer according to DE 10136433 AI. Cavities between the motherboard and the reinforcement board need not be provided either. Rather, a coating, in particular of the reinforcement board (s), can advantageously be provided with the glass material. Sintered glass is particularly preferably used as such a glass material. This can not only be applied without problems, but also also proves to be very suitable for use with metals in terms of melting temperatures in hot forming.

In the case of advantageous provision of shark warming of a base plate provided with a connection layer and at least one reinforcement plate together, an adhesive in particular can be used as the connection layer. This can melt during the forming process, harden on cooling and form a firm connection between the base plate and the at least one reinforcement plate.

In the case of a structural part produced by the method according to the invention, a connection layer is preferably provided between a shaped base plate and at least one reinforcement plate in the form of an adhesive and / or melted and solidified glass material, which connects the base plate and the at least one reinforcement plate and / or several reinforcement plates to one another.

A reinforcement board is preferably arranged and fixed on the base board and / or aligned to it by suitable means, or a plurality of reinforcement boards are arranged next to and / or one above the other on the

Main board arranged and fixed and / or aligned by suitable means to each other and / or to the main board. Particularly preferably, if only one reinforcement board is provided, it is arranged and fixed on the base board and / or aligned to it by suitable means, or if a plurality of reinforcement boards are provided, these are overlapping and / or abutting and / or spaced from one another in a partial area on the

Main board fixed and / or aligned with each other by suitable means. By providing several reinforcement boards side by side with and without spacing from one another, stresses within a shaped workpiece or sheet metal structural part can be avoided or at least reduced, and rigidity increases can be carried out in a targeted manner, in particular if different material thicknesses are provided for the base plate and reinforcement plate (s). By providing several reinforcement boards one above the other, additional material reinforcements and thus very different stiffnesses can be achieved across the surface of the structural part. Differences in stiffness can also be generated by overlapping several reinforcement boards in their respective edge regions. However, only one reinforcement board can be provided in each case, which was possibly previously assembled from several parts, in particular of different material thickness. Instead of providing a fixation or connection of the blanks to one another before the forming process, it is also possible to position the blanks in a mutually aligned manner and to shape them without a connection to one another. To fix the position or to maintain the mutual positioning, in particular stud bolts or similar devices can be particularly preferably provided in the forming tool or the forming press.

The reinforcing boards are preferably joined to one another in an abutting manner before the shaping process, in particular by providing a weld seam or other connecting seam. Depending on the forming temperature and the forming mode, this butt seam can be leveled out during forming, so that no uneven transition points remain.

The blanks are preferably fixed to one another by additional connections, in particular by welding, riveting or clinching, before the hot or hot forming and / or after the hot or hot forming or another connection method. As a result, the unambiguous position of the reinforcing board (s) applied in a targeted manner at certain points on the surface of the base board is fixed in particular before the shaping, so that this essentially does not change during the shaping. After the reshaping, a fixation proves to be advantageous especially in the case of connections, which may otherwise be easily detached, between the base plate and the reinforcement plate (s), since an additional point connection can counteract unwanted shearing.

In contrast to the soldered connections according to DE 10049660 AI, the provision of an adhesive proves to be advantageous in that the heating temperature does not need to be kept in a range that is compatible with the solder, but rather in a range that is particularly suitable for semi-warm but also for hot forming Range can be set. In addition, the problem of flux corrosion, which is usually used for a soldering process, is avoided.

In order to explain the invention in more detail, two exemplary embodiments are described below with reference to the drawings. These show in:

Figure 1 to 6 is a schematic view of the sequence of a hot forming process according to the invention by separating three reinforcing boards mounted on a base plate, and

Figures 7 to 10 is a schematic view of the sequence of a second embodiment of an inventive Semi-hot forming process with the provision of a surface coating on reinforcement boards.

FIG. 1 shows a first step of a hot forming process in which a flat, flat base plate 1 is first provided with three flat and flat reinforcement plates 2, 3, 4 of smaller dimensions than that of the base plate. This is also indicated by the arrows P. The reinforcement boards 2, 3, 4 are fixed on the surface 10 of the base board by a number of connection points, for example by six welding points 5, whereby a composite board 6 is formed. Alternatively, fixation can also be carried out using rivets, clinching or any other connection method. As a result, the blanks are secured against shifting during subsequent forming. The number of connection points depends on the sheet thickness of the blanks as well as the extent of the forming. Again, alternatively, the boards 1, 2, 3, 4 can only be aligned with one another without being fixed by welding points or the like. The reinforcement boards are arranged side by side and adjacent to each other on the motherboard. Their position and dimensions depend on the desired local rigidity. You can therefore also use reinforcement boards e.g. have different material thicknesses and / or different material thicknesses of the reinforcement boards, possibly also by joining several reinforcement boards together.

After fixing the boards to each other, the resulting one

Composite board 6 heated in an oven 7, as outlined in Figure 2. Here, the composite board is heated to a temperature suitable for hot forming, in particular to a temperature in the Range of 950 ° C. Alternatively, semi-hot forming can also be carried out, for example at temperatures in the range below 850 ° C., in particular 500 to 700 ° C., for example around 600 to 650 ° C. The heated composite blank is then passed on to a forming press 8, as outlined in FIG. 3. In the forming press, the warm or hot forming of the base plate and reinforcing plates fixed to one another takes place. After hot forming, the composite board is tempered by appropriate temperature control.

The deformed composite plate in the form of a molded part which can be removed from the forming press 8 is shown in a perspective view in FIG. The three reinforcement blanks are fixed on the surface 10 of the base plate 1, which surface is now formed on the inside of the molded part. Their position relative to one another has not changed during the shaping process.

Since no corrosion-preventing and sealing connection layer has been provided between the boards, the shaped reinforcement boards and the base board are separated again in the next processing step, which is outlined in FIG. The separation can take place after the warm or hot forming within the forming tool.

After the shaped blanks have been separated, they are provided on the surfaces facing one another with a connecting layer 11, for example with an adhesive layer and / or a sealant, which preferably also enables the surfaces to be joined or adhered to one another. The three reinforcement boards can either be applied on a common connection layer or on separate connection layers. Then the molded reinforcement boards 2, 3, 4 are placed back on the molded one Base board 1 added, an at least adhesive connection between the surfaces of the boards is now achieved by the connecting layer. The connecting layer preferably has a thickness such that the accuracy of fit of the jointly deformed boards is not jeopardized. In particular, it lies between the boards in such a way that an optimal, essentially gap-free fit is ensured. The addition of the shaped reinforcement boards 2, 3, 4 is indicated in FIG. 6 by arrows 9. The reinforcement boards can already be connected to one another, in particular before forming, in order to enable simple separation and reassembly.

In order to additionally strengthen the connection between the motherboard and the reinforcement boards, connection points in the form of e.g. Spot welds, rivets, etc. are provided. Depending on the choice of the connection layer used, this additional connection can in principle also be omitted.

The shaped reinforcement boards serve e.g. as internal reinforcement, the shaped base plate as external reinforcement of a vehicle B-pillar.

Figure 7 shows the first processing step of an alternative method for warm or hot forming of blanks. The reinforcement boards 2, 3, 4 are first provided with a surface coating 20, 30, 40. This surface coating consists of a material which melts under the influence of heat and, at the latest when the shaped boards are cooled, bonds with them in an adhesive or adhesive manner, in particular an adhesive. When using hot forming, a glass material, such as sintered glass, can advantageously be used. As an alternative to providing the surface coating only on the surfaces of the reinforcement boards The surface 10 of the motherboard and / or both the surface of the motherboard and that of the reinforcement boards can also be provided with a surface coating which, when heated, also enables a connection to the reinforcement boards, for example in the manner of a multi-component adhesive.

With their coated surfaces 21, 31, 41, the reinforcement boards 2, 3, 4 are then attached to the base board 1 and, in the case shown in FIG. 7, fixed at various points, for example by welding spots 5.

This unit of composite board 60 thus created is subsequently introduced into an oven 7, as can be seen in FIG. In this, the composite blank is heated to a temperature suitable for semi-hot forming (or possibly hot forming) and passed on to the forming press 8 (FIG. 9). It is used for semi-hot forming or hot forming with appropriate temperatures. During the forming process, the surface coating of the blanks melts and connects to the respective adjacent blank surface. A connection layer 12 is therefore formed directly during the forming, which enables a sealed and at the same time firmly connected unit of the shaped blanks.

During the tempering of the board material, the connecting layer 12 is cooled and hardens in the process. Any gaps that remain or arise during the shaping between the base board and the reinforcement boards are filled by the connecting layer, as a result of which a tight unit for protection against corrosion can be created. In addition to the existing and remaining during the hot or hot forming joints in the form of, for example Welding points, further or these can be provided again, if necessary, for the additional connection of the shaped boards to one another. In principle, however, the combination of the fixing connection points applied before the forming and the connection layer can ensure a sufficiently firm hold of the shaped blanks on one another.

A finished molded part can be removed from the forming press 8, as is shown in FIG. 9, which can be used as a structural part in vehicle construction, etc., after cutting to size, which usually follows the forming.

In addition to the embodiments described above and shown in the figures, numerous others can be formed, in each of which a separation of semi-hot or hot-formed blanks or sheets is provided after the shaping and before the application of a connecting layer or the blanks or sheets, without being separated after the warm or hot forming, directly meanwhile by melting a coating which is provided on at least one plate of a pair of plates lying one on top of the other.

LIST OF REFERENCE NUMBERS

1 motherboard

2 reinforcement board 3 reinforcement boards

4 reinforcement boards

5 spot weld

6 composite board

7 furnace 8 forming press

9 arrows

10 Surface of the motherboard

11 connection layer

12 connection layer 20 surface coating

21 coated surface

30 surface coating

31 coated surface 40 surface coating 41 coated surface

60 composite board

P arrows

Claims

Expectations 1. A method for forming sheet metal, in particular for warm or hot forming of blanks (1, 2, 3, 4), in a forming tool (8), one or more reinforcing blanks (2, 3, 4) are applied, the base board (1) and the at least one reinforcement board (2, 3, 4) are fixed to one another and / or aligned with one another by suitable means, and the base board (1) and the at least one reinforcement board (2, 3, 4) 4) are reshaped together, the base plate (1) and the at least one reinforcing plate (2, 3, 4) being separated after the reshaping, provided with at least one connecting layer (11) and joined together again. 2. The method according to claim 1, characterized in that the shaped blanks (1, 2, 3, 4) are separated according to their shape, subsequently the at least one connecting layer (11) is applied and the shaped blanks (1, 2, 3, 4 ) are put together again. 3. The method according to claim 1, characterized in that an adhesive, in particular a hot glue, is applied to the base plate and / or the at least one reinforcing plate before, during or after the semi-hot or hot-forming process, in particular during the cooling phase of the shaped plates (1 , 2,3,4), especially within the U-shaped tool. 4. The method according to any one of the preceding claims, characterized in that the connecting layer is formed from a multicomponent adhesive, the components of which on the surface (10) of the base board (1) and the at least one reinforcement board (2, 3, 4) or the surfaces of the reinforcement boards (2, 3, 4 ) are applied. 5. A method for forming metal sheets, in particular for warm or hot forming of blanks (1, 2, 3, 4), in a forming tool (8), one or more reinforcing blanks (2, 3, 4) are applied, the base board (1) and the at least one reinforcement board (2, 3, 4) are fixed to one another and / or aligned with one another by suitable means, and the base board (1) and the at least one reinforcement board (2, 3, 4) 4) are formed together, in particular according to one of the preceding claims, characterized in that a surface coating (20, 30, 40) is applied to the at least one reinforcement board (2, 3, 4) to form a or as a connecting layer. 6. The method according to claim 5, characterized in that the surface coating (20, 30, 40) is applied to the at least one reinforcing plate (2, 3, 4) before the warm or hot forming process, the surface coating during the warm or hot forming melts and forms a connection between the base plate (1) and the at least one reinforcement plate (2, 3, 4). 7. The method according to claim 5 or 6, characterized in that the connecting layer consists of an adhesive and / or glass material applied as a coating on the base plate (1) and / or the at least one reinforcement plate (2, 3, 4), which melts during the shaping process and, during cooling, forms a firm connection between Forms motherboard and reinforcement board (s). 8. The method according to claim 7, characterized in that the glass material sintered glass and / or the adhesive is an adhesive suitable for high or very high temperatures. 9. The method according to any one of the preceding claims, characterized in that the connecting layer is designed as a pattern or mask on the surface of the at least one reinforcement board (2, 3, 4) and / or the base board (1), in particular the edge region of the reinforcement board essentially completely surrounding. 10. The method according to any one of the preceding claims, characterized in that a reinforcement board on the base board (1) is arranged and fixed and / or aligned by suitable means to this or that a plurality of reinforcement boards (2,3,4) alongside and / or arranged and fixed one above the other on the motherboard (1) and / or aligned to one another and / or to the motherboard (1) by suitable means. 11. The method according to any one of the preceding claims, characterized in that a reinforcement board is arranged on the base board (1) and fixed and / or aligned to it by suitable means or in that a plurality of reinforcement boards (2, 3, 4) overlap and / or abut each other and / or with each other in a partial area Fixed to each other on the motherboard (1) and / or aligned with each other by suitable means. 12. The method according to claim 11, characterized in that a plurality of reinforcing boards are joined together in an abutting manner before the shaping process, in particular by attaching a weld seam or another connecting seam. 13. The method according to any one of the preceding claims, characterized in that the base board (1) and the reinforcement board (s) (2,3,4) have different material thicknesses. 14. The method according to any one of the preceding claims, characterized in that the blanks (1, 2, 3, 4) are fixed to one another by means of additional connections, in particular by welding, riveting, before warm or hot forming and / or after warm or hot forming , Enforce or any other connection method. 15. A method for forming sheet metal, in particular for warm or hot forming of blanks (1, 2, 3, 4), in a forming tool (8), with a base plate (1) for partial reinforcement one or more reinforcement boards (2, 3, 4) are applied, the base board (1) and the at least one reinforcement board (2, 3, 4) are fixed to one another and / or aligned to this by suitable means, and the base board (1) and the at least one reinforcement board (2, 3, 4) are formed together, in particular according to one of the preceding claims, characterized in that the base board (1) and the at least one reinforcement board (2, 3, 4) are provided with a connecting layer and formed together in a semi-warm manner become. 16. The method according to claim 15, characterized in that the blanks are formed at temperatures below 850 ° C, in particular at temperatures between 500 and 730 ° C, in particular 500 and 700 ° C, in particular 500 and 650 ° C. 17. Structural part, produced by a method according to any one of the preceding claims. 18. Structural part according to claim 17, characterized in that a connecting layer (12) between a shaped base plate (1) and at least one reinforcing plate (2,3,4) in the form of an adhesive and / or melted and solidified glass material is provided, which Main board (1) and the at least one reinforcing board (2, 3, 4) or a plurality of reinforcing boards (2, 3, 4) are connected to one another. 19. Structural part according to claim 17 or 18, characterized in that the reinforcement boards or the at least one reinforcement board (2, 3, 4) and the base board (1) have different material thicknesses. 20. Structural part according to one of claims 17 to 19, characterized in that the reinforcing boards (2, 3, 4) are connected to one another.