EP2540405B1 - Device for manufacturing circuit boards of varying thicknesses - Google Patents

Description

The invention relates to a method for producing boards, which have different thicknesses over their length.

From the JP 63-040604 A is a method for the production of steel blanks with different thicknesses known. For this purpose, a rolling device is provided with preset roll gap, which is preceded by a heater and a temperature measurement. The desired heat output is determined from data such as material temperature, target temperature distribution, thickness, width and specific heat and a reference feed rate. The preamble of claim 1 is based on JP 63-040604 A , From the DE 197 04 300 A1 For example, there is known a method for producing boards of different thicknesses by deformation of an approximately uniformly thick starting material. The starting material is first heated in an induction heating system to a temperature above the recrystallization temperature. Subsequently, a partial rolling deformation of the starting material takes place in the rolling direction with regions varying thicknesses.

From the DE 198 46 900 A1 For example, a method and an apparatus for producing a metal strip are known. The different thickness regions of the strip are produced by hot rolling by sectioning the strip prior to hot rolling by cooling or heating to a different temperature. In this way, the band experiences a different in the individual sections, due to the different temperature setting Have obtained a yield stress value, with a substantially constant rolling force a different thickness decrease. For rolling with constant rolling force a hydraulic delivery is provided, which moves the nip during rolling.

From the EP 2 111 937 A1 For example, a method of making sheet metal blanks varying in thickness is known. The starting material is prefabricated a sheet metal blank with variable thickness as "Tailor Rolled Blank" or as "Tailor Welded Blank". Subsequently, the sheet metal plate is partially reworked, in particular embossed, so that the thickness is changed again locally. It is described that in the production of thick-optimized sheet metal blanks for the production of press-hardened hot-formed parts it is advisable to emboss the sheet-metal plate heated for press-hardening first by a rapid impact. Due to the short contact time with the embossing tool, only so little heat would be extracted from the workpiece that the subsequent press hardening could be carried out "from a heat".

A disadvantage of the methods used today is the high cost of heating the coils and the complexity of the rolling stands for rolling the partially differently heated coils or boards to partially different thicknesses.

The present invention has for its object to propose a simplified method for the production of boards with different thicknesses, which allows a targeted regional heating of boards and a blading of the boards by means of a simple and inexpensive rolling mill on different thicknesses.

The solution consists in a method for producing boards with different thicknesses of a metallic steel material with the method steps: manufacture of boards from a strip material;
Area-wise changing the temperature of the boards, wherein areas of different temperatures are generated in the boards; Rolling the partially temperature-changed blanks in a rolling tool with a nip position, wherein the nip position is kept constant during rolling, wherein sections of different thickness are produced in the boards due to the different temperature ranges; wherein the boards are heated after rolling and hot worked after heating in a forming tool; wherein the boards with the areas which have the highest temperatures after the regional temperature change, during the subsequent process steps of rolling and heat treatment to insert into the forming tool always have a temperature of about 500 ° C for steel materials.

The advantage of the method with the specified sequence of the individual method steps is that different temperature zones are generated by the regional variation of the temperature. By the different ones Temperature zones have the different areas of the boards different flow resistance. In this case, hotter areas have a lower flow resistance and are therefore more severed than colder areas of the board. Due to the different flow resistances, sections of different thickness are produced on the board by the subsequent rolling. In this case, the areas heated higher before rolling have a smaller thickness after rolling than the lower heated areas. Overall, with the method according to the invention, by appropriately setting the temperature zones of the blank prior to rolling, an optimized thickness profile of the blank can be produced after rolling, which is adapted to the later component requirements.

A board is understood to be a sheet metal element which is produced from a strip material or from a coil. That is, the process step of the area-wise temperature change of the board is preceded by a production of the board from a strip material. It is understood that between the separation of boards from the strip material and the area-wise temperature change of the board other process steps may be interposed, for example, a heat treatment. The production of the boards from the strip material or the coil can be arbitrary and depends on the final contour of the board to be manufactured. For example, the boards can be made by simply cutting the strip material into individual elements having at least two parallel side edges, or by cutting or punching individual elements with an individual circumferential contour from the strip material. These cut-out elements with individual circumferential contours can also be referred to as shaped cuts or contour cuts.

The advantage of using blanks for the regional temperature change is that it is also possible to generate temperature gradients transversely to the production direction or to the subsequent rolling direction. During rolling, these lead to an unsymmetrical deformation of the blank in relation to the rolling direction, which would not be possible with strip material. This advantageously provides maximum flexibility with regard to the geometric design of the board to be produced or of the end product to be produced from the board.

The rolling takes place after separation of the boards is carried out at a constant nip. This means that the nip position remains at least largely constant when passing through the blank by the rolling tool, preferably in an unregulated process. In this context, nip is the term for the roll opening including the roll jump at the contact surfaces of the rolling stock with the rolls over the roll bale length. Roll skip is the name given to an enlargement of the roll opening when the rolling stock is punctured by stretching the parts of the roll stand. The rolling force can, in contrast to the nip, change as it passes through the board. The transitions between two board sections with different strip thickness are due to the temperature distribution in the board and can be kept very short with a corresponding partial temperature change before rolling, in contrast to controlled rolling stands. The force-working requirement is greatly reduced by the temperature-dependent flow resistance, so that boards with different thicknesses can be produced in a large width economically.

According to a preferred embodiment, the different temperature ranges are generated according to the later desired thickness profile of the board. In this case, the shape and the extent of the temperature ranges in the longitudinal and in the transverse direction of the board can in principle be chosen so that the board has the desired thickness profile after rolling.

In particular, according to a simple first embodiment, at least one region, preferably a plurality of regions, of the regions with different temperatures is heated or cooled to a constant temperature transversely to the rolling direction. The juxtaposed in the longitudinal direction of the board areas of the board, each with the adjacent area different temperature lead during rolling to a change in thickness of the board in the longitudinal direction or in the rolling direction of the board. The number and distribution of the areas with different temperature is basically freely selectable depending on the desired thickness profile of the board, the number is in particular between two and six.

According to a second possibility, it can be provided that at least one region, if appropriate also several regions, are provided with a variable temperature transversely to the rolling direction. This makes it possible that the board during the subsequent rolling process undergoes a corresponding change in thickness transverse to the rolling direction. Again, that the number and distribution of the areas with different temperature depending on the desired thickness profile of the board to be produced can be adjusted.

According to a third possibility, which represents a combination of the first and the second possibility, both temperature ranges can be generated, which extend at uniform temperature transverse to the rolling direction, as well as temperature ranges, which have an additional temperature gradient transverse to the rolling direction. The latter third option achieves the highest degree of flexibility with regard to the subsequent thickness progression of the board after rolling in the longitudinal and in the transverse direction. In particular, a three-dimensional thickness structure of the board can be produced herewith.

According to a first embodiment, the region-wise changing of the temperature takes place starting from a homogeneous first temperature of the board by heating at least one area of the board to a higher second temperature. By homogeneous first temperature is meant that the board uniformly has the same temperature before the area-wise temperature change. By at least one region, it is meant that one or more regions are heated to an individual temperature. When just one area is heated, two areas of different temperature are created. The height of the temperature to which the board is heated depends essentially on the material or on the strength of the material. When using a steel material, the at least one region of the board is preferably heated to a second temperature of 400 ° C to 1250 ° C, in particular from 600 ° C to 800 ° C. When using an aluminum material, the board is preferably heated to a second temperature of 150 ° C to 500 ° C.

The partial heating of the circuit board can be effected, for example, by means of a stamp, which is brought into contact with the circuit board in such a way that the circuit board assumes at least approximately the temperature of the stamp. In this case, the stamp would be designed as a heating die, which preferably has differently controlled temperature zones. Alternatively, the heating in regions can also be carried out inductively by means of one or more current rollers through which the circuit boards are guided, wherein it is provided in particular that the different temperature zones of the circuit boards are produced by varying the power of the current rollers during passage of the circuit boards.

According to a second embodiment, the region-wise changing of the temperature is accomplished from a homogeneous first temperature of the board by cooling. For this purpose, the boards are first heated homogeneously to a higher first temperature before the area-wise changing of the temperature. Subsequently, the temperature is changed in regions by cooling at least one area of the board to a lower second temperature. The fact that at least one area is cooled, at least two areas arise with mutually different temperature. Of course, as many other areas can each be cooled to an individual temperature. When using a steel material, the homogeneous first temperature to which the board is heated is between 950 ° C and 1250 ° C. The subsequent partial cooling of the regions takes place at lower second temperatures, which are in particular between 400 ° C. and 950 ° C., preferably between 600 ° C. and 800 ° C.

The partial cooling of the board is preferably carried out by means of a punch, which is brought into contact with the board in such a way that the board assumes at least about the temperature of the stamp. In this case, the stamp would be designed as a cooling stamp. The stamp may preferably have individually controllable cooling zones, so that the temperature zones of the board can be individually adapted to the later to be produced thickness profile.

According to an embodiment that applies to both embodiments, that is, both for the partial heating and the partial cooling, the boards are subjected to a heat treatment after rolling, preferably a normalization annealing. For this purpose, the boards are preferably heated to a temperature of 950 ° C to 1250 ° C and when using aluminum material to a temperature of 150 ° C to 550 ° C when using steel material. The heating preferably takes place in a heating furnace. This heat treatment produces a uniform microstructure in the board over all sections of different thickness.

After the heat treatment, the board is further processed to the final product. The subsequent process step comprises a forming process, such as deep-drawing. Subsequently, the component can be cured, or annealed, that is, hardening followed by tempering. Particularly advantageous is the use of a thermoforming process. In this case, the board is formed in a thermoforming mold to the intended shape and cured. In the context of thermoforming, it is also conceivable that only portions of the thermoforming tool are cooled, so that only the sections of the workpiece are cured, which come into contact with the cooled portions of the thermoforming tool. The remaining sections of the workpiece retain a lower hardness. For thermoforming with simultaneous curing, a cooled mold is required which has cooled areas in the sections to be cured of the board or of the end product to be produced therefrom, or is optionally completely cooled.

A device for producing boards with different thicknesses of a metallic material according to the method according to the invention, with one or more of the above-mentioned method steps, comprises in the order given: a tool for separating boards from a strip material; a temperature-changing tool, with which areas of different temperatures can be generated in the boards; and a rolling tool with a constant nip position, with which the temperature-changed circuit boards are rollable, so that in the boards due to the different temperature ranges sections of different thickness can be generated.

The device has the same advantages as the method, so that reference is made in this regard to the above description. In particular, the constant roll gap setting of the rolling tool, preferably in an uncontrolled process, is favorable in terms of simple and efficient production. The change in material thickness occurs solely due to different roller jumps of the rolling tool when passing through the boards, which in turn is due to the different flow resistance in the board material or the partially different temperatures of the material. The fact that the temperature-changing tool is preceded by a tool for separating strip material to boards, is the highest for the geometric design of the board to be produced or the end product to be produced from this Given flexibility. Thus, for example, boards or products with variable thickness profiles can be generated transversely to the rolling direction.

According to a preferred embodiment, the temperature-changing tool on at least one stamp, which can be heated or cooled. With the stamp, the temperature of the board can be partially increased or decreased in one or more areas compared to other areas. The size and shape of the stamp is preferably based on the shape and size of the temperature zones to be generated or the thickness profile of the board to be produced during the rolling process. Preferably, the stamp has a plurality of areas in which the temperature is individually adjustable. In this way different temperature zones can be created with a stamp on the board.

In the first possibility, according to which the punch is designed as a heating punch, heating wires are preferably provided in the punch, which can heat the punch at least in some areas.

In the second possibility, in which the stamp is formed as a cooling die for partial cooling of the board, this preferably has channels through which a cooling medium can flow to cool the stamp. For variable adjustment of the different temperature zones in the board, it is particularly advantageous if the flow rate of the cooling medium through the channels is controllable. Preferably, a plurality of cooling circuits are provided by the stamp, which are flowed through by cooling medium. By individually adjusting the flow rate of the cooling medium through each individual channel, different temperature zones can be generated with a cooling stamp. Thus, it is possible, for example, that a first area with 600 ° C, a second area with 750 ° C and a third area with 900 ° C can be generated in the board with a cooling stamp. The same naturally applies mutatis mutandis to a Heizstempel according to the first possibility, which may have correspondingly different heating zones.

According to a preferred embodiment, which applies to both possibilities, the at least one stamp is made of a metallic material with good thermal conductivity, in particular of copper or of a copper-containing material.

The rolling tool is preferably designed so that the gap width is constant during rolling. As a result, the power-work demand can be kept very low, which has a favorable effect on the production costs and time. However, it goes without saying that a tool for flexible rolling can also be used, with which a particularly high degree of flexibility with regard to the thickness profile of the boards to be produced is achieved.

According to the invention, the device comprises the heat treatment device, which is connected downstream of the rolling tool. In the heat treatment device, which is designed in particular as a heating furnace, the boards can be heat-treated, preferably normalized.

The heat treatment device is connected downstream of the forming tool, which is designed in the form of a thermoforming tool in which the boards can be reshaped and at least partially cured. The combination of the area-wise temperature change of the blanks, subsequent rolls, heating and hot forming is particularly favorable, since this allows a very efficient production of sheet metal blanks with variable thickness over the length or the width. The heat input into the board during manufacture, that is, while passing through the individual device stations can be kept low, which in turn has a favorable effect on the production speed and costs. It is particularly advantageous if the boards with the areas which have the highest temperatures after the regional temperature change during the subsequent process steps of rolling and heat treatment to insert into the forming always a temperature of about 500 ° C, in particular of about 600 ° C, for steel materials.

Figur 1

ein erfindungsgemäßes Verfahren zur Herstellung einer Platine mit unterschiedlichen Dicken in einer ersten Ausführungsform

1. a) mit den einzelnen Verfahrensschritten;
2. b) der Temperaturverlauf für zwei Bereiche über der Zeit;

Figur 2

ein erfindungsgemäßes Verfahren zur Herstellung einer Platine mit unterschiedlichen Dicken einer zweiten Ausführungsform

1. a) mit den einzelnen Verfahrensschritten;
2. b) der Temperaturverlauf für zwei Bereiche über der Zeit;

Figur 3

beispielhaft eine Platine hergestellt nach einem Verfahren bzw. mit einer Vorrichtung gemäß Figur 1 oder Figur 2 in einer weiteren Ausführungsform

1. a) in Draufsicht nach der partiellen Temperaturbehandlung und vor dem Walzprozess,
2. b) schematisch in Seitenansicht vor dem Walzprozess,
3. c) schematisch in Seitenansicht nach dem Walzprozess;

Figur 4

beispielhaft eine Platine hergestellt nach einem Verfahren bzw. einer Vorrichtung gemäß Figur 1 oder Figur 2 in einer weiteren Ausführungsform

1. a) in Draufsicht nach der partiellen Temperaturbehandlung und vor dem Walzprozess;
2. b) in Draufsicht nach dem Walzprozess;
3. c) schematisch in Seitenansicht nach dem Walzprozess;
4. d) im Querschnitt nach dem Walzprozess durch einen Abschnitt gemäß Schnittlinie D-D aus Figur 4b).

Preferred embodiments will be explained below with reference to the drawing figures. Hereby shows:

FIG. 1

an inventive method for producing a board with different thicknesses in a first embodiment

1. a) with the individual process steps;
2. b) the temperature profile for two areas over time;

FIG. 2

an inventive method for producing a board with different thicknesses of a second embodiment

1. a) with the individual process steps;
2. b) the temperature profile for two areas over time;

FIG. 3

By way of example, a circuit board produced by a method or with a device according to FIG. 1 or FIG. 2 in a further embodiment

1. a) in plan view after the partial temperature treatment and before the rolling process,
2. b) schematically in side view before the rolling process,
3. c) schematically in side view after the rolling process;

FIG. 4

By way of example, a circuit board produced by a method or a device according to FIG. 1 or FIG. 2 in a further embodiment

1. a) in plan view after the partial temperature treatment and before the rolling process;
2. b) in plan view after the rolling process;
3. c) schematically in side view after the rolling process;
4. d) in cross section after the rolling process through a section according to section line DD FIG. 4b ).

FIG. 1 shows a method according to the invention for producing a circuit board 10. The sheet metal blank 10 is preferably made of a metallic material, for example of a steel material or aluminum, and may also be referred to as a sheet metal blank. A process procedure A is shown.

Under board 10 is understood in this context, a sheet metal element, which can be made in particular of a strip material or a coil. In this case, the board can be made by simply cutting the strip material into individual elements or by cutting or punching of individual elements of the strip material.

In method step A1, the circuit board 10 is treated by means of a temperature-changing tool 30. The board 10 receives different areas 11, 12, 21, which have different temperatures. In the present example, the region 11 has a temperature of 800 ° C, the second region 12 has a temperature of 600 ° C. The transition region 21 lying between the first region 11 and the second region 12 has a variable temperature, which decreases from the first region 11 to the second region 12.

In the FIG. 1b ) shown in solid line shows the temperature profile for the first region 11 over time. Here it can be seen how the temperature, starting from the initial temperature of 0 ° C, initially increases sharply until the target temperature T _A1,11 of 800 ° C is reached. Accordingly, the dashed line shows the temperature profile for the second region 12. Here is also seen how the temperature increases with time until the target value of T _A1,12 = 600 ° C is reached.

After the area-wise temperature treatment of the board 10, this is subjected to a rolling process in the subsequent process step A2. This is done by means of a rolling tool 40, which comprises a plurality of rollers 41, 42. As a result of the different temperature ranges 11, 12, 21 generated in method step A1, the circuit board 10 has correspondingly different flow resistances. In this case, the hotter first region 11 has a lower flow resistance, which is why it is more heavily rolled off. In contrast, the cooler second region 12 of the board has a higher flow resistance, so that it is less severed. Due to these different flow resistances, portions 11 ₂ , 12 ₂ , 21 _{2 of} different thickness are produced on the blank 10 by the rolling process A2. The After the rolling process, the board is provided with subscripts centered around the number two. It can be seen that the board 10 ₂ after passing through the rolling tool 40 has a first portion 11 ₂ with a smaller sheet thickness and a second portion 12 ₂ with a larger sheet thickness and an intermediate transition portion 21 ₂ .

When passing through the blank 10 by the rolling tool 40, the nip position remains constant, d. H. the distance between the rollers is not changed when passing through the sheet metal blank 10. The thickness profile results solely due to the different temperature ranges 11, 12, 21 of the board 10. Overall, this results in a low power work demand. It will be understood, however, that a flexible rolling in which the nip position is varied during the process can also be used. This results in a further increased flexibility and further possibilities of individual design of different thickness profiles on the boards 10.

In FIG. 1b ), the temperature profile T _{A2 is shown} before, after and during rolling. Here, the solid line again shows the temperature profile for the region 11 or the section 11 ₂ present after the rolling process. Before rolling, the temperature decreases slightly and then more during rolling, up to a temperature of about 700 ° C. After the rolling process, the rolled board 10 ₂ further cools, so that the temperature decreases accordingly. The temperature profile T _A2,12 for the second region 12 runs as far as possible parallel to the temperature range T _A2,11 for the first region 11 with a reduced by about 200 ° C temperature.

In the subsequent method step A3, the rolled board 10 _{2 is} subjected to a heat treatment. The board or its sections are provided after the heat treatment with subscript by three digits indices. The heat treatment is preferably carried out in a furnace 50. By the heat treatment solidification of the material resulting from rolling is reduced or dissolved and the rolled plate 10 ₃ again receives a higher ductility and ductility. In this way, the board can be 10 ₃ in the following steps easier to further process, in addition, the material properties of the final product to be produced are positively influenced. It is understood that the heat treatment in method step A3 is only optional, that is to say that the board 10 ₂ can in principle also be further processed without subsequent heat treatment.

How out FIG. 1b ), the board 10 _{3 is} heated to about 950 ° C. In this case, the thinner first board section 11 ₃ heats up faster than the thicker board section 12 ₃ .

After the heat treatment according to method step A3, the board 10 _{3 can be} further processed. By way of example, a shaping machining in a thermoforming tool 60 is shown here. The board or its sections are provided in connection with the thermoforming process with subscripted by the number four indices. When thermoforming according to method step A4, the board 10 _{4 is} subjected to a shaping treatment and at the same time strongly cooled or hardened. This can also be seen in the temperature profile, namely for the thinner first section 11 ₄ (temperature T _A4,11 ) shows a sharp drop in temperature from 950 ° C to below 200 ° C. The thicker second board section 12 ₄ cooled slightly slower, as the dashed line (temperature T _A4,12 ) can be seen. It is understood that other than hot forming processes can be used as a shaping processing. By way of example, a further processing by means of pressing or deep drawing may be mentioned here.

The FIGS. 2a) and 2b ) show a method according to the invention for the production of a sheet metal blank with different thicknesses according to a second process procedure B. This corresponds in further parts to the process according to FIGS FIGS. 1a ) or 1b), so that reference can be made to the above description with regard to the similarities. The same or modified components are provided with the same reference numerals, as in FIG. 1 , In the following, essentially the differences of the present method will be discussed.

The peculiarity of the procedure B according to FIG. 2 consists in that the sheet metal blank is first heated in a step B0. The temperature to which the sheet metal blank 10 is heated depends on the material or the strength of the material; this is preferably between 900 ° C and 950 ° C for a steel material. After heating in step B0, a partial temperature change of the sheet metal blank 10 is made in the subsequent step B1. This takes place in the present embodiment by areawise cooling of the sheet metal blank 10. The board 10 ₁ in the present example, a first region 11 ₁ , which is cooled to 800 ° C, and a second region 12 ₁ , which is cooled to 600 ° C. , Between the two regions 11 ₁ , 12 ₁ is a transition region 21 ₁ with a variable temperature profile over the length or the subsequent rolling direction.

It is in FIG. 2b ) the temperature profile T _{B of} the sheet metal blank 10 and the first region 11 and the second region 12 over time, or along the various process steps B0 to B4, shown. In this case, the solid line shows the temperature profile T _B11 for the first area 11, while the dashed line shows the temperature profile T _B12 over the time for the second area 12. It can be seen in the context of the second method step B1 that the first region 11 _{1 of} the board 10 _{1 is} cooled from 950 ° C. to about 800 ° C. (temperature _curve T _B1,11 ). The second region 12 ₁ experiences a greater cooling, namely to about 600 ° C (temperature _curve T _B1,12 ).

The present at this time product corresponds to the board 10 ₁ from the first procedure A according to FIG. 1a ), b), as present after the first process step A1. The process steps B2, B3 and B4 following the second process procedure B correspond to the process steps A2, A3 and A4 according to FIG FIG. 1 , so that reference is made in this regard to the above description.

The peculiarity of the present embodiment according to FIG. 2 is that the regionally varying the temperature T _B1 starting from the homogeneous first temperature, which takes place after the heating in step B 0, is accomplished by cooling. This process procedure has the advantage that the heat from the previous heating process according to process step B0 can be used, so that the present process is very effective. The partial cooling of the circuit board 10 is preferably carried out by means of a punch 30, which is brought into contact with the circuit board 10 in such a way that the circuit board 10 assumes the temperature of the punch 30. The stamp 30 has in particular a plurality of cooling zones, which are individually adjustable. For example, the plunger 30 may include a plurality of channels through which a cooling medium may flow to cool it. For variable setting of different temperature zones in the circuit board 10, it is provided that the flow rate of the cooling medium through the channels is controllable. To produce different temperature ranges 11, 12, 21 in the circuit board 10, the plunger 30 has a plurality of cooling circuits through which cooling medium flows. It can be generated by individual adjustment of the flow rate of the cooling medium through each channel different temperature zones.

The stamp is preferably made of a metallic material with good thermal conductivity, for example of copper or of a copper-containing material.

It is understood that the two embodiments for the different areas of the board 10, which in the FIGS. 1 and 2 are shown, are exemplary only. The number and distribution of the regions 11, 12, 21 with different temperatures T ₁₁ , T ₁₂ , T ₂₁ is basically freely selectable and can be adapted to those with regard to the thickness profile of the workpiece to be manufactured. The number of regions 11, 12, 21 having different temperatures T ₁₁ , T ₁₂ , T ₂₁ is preferably between two and six, wherein more regions are also conceivable.

FIG. 3 shows a further example of a board after the partial change of the temperature according to the method step A1 or B1. It can be seen that the circuit board 10 in the present case has six regions 11-16 each having an individual temperature T ₁₁ -T ₁₆ . These are each shown as white areas. Between the six areas 11-16 each having a uniform temperature T ₁₁ -T ₁₆ are respectively Transition regions 21-25, in which the temperatures T ₂₁ -T _{25 are} variable. These transition regions 21-25 are shown hatched. Here, the temperature continuously changes from one temperature range to the next. The manufacturing or later rolling direction is indicated by an arrow R.

FIG. 3b ) shows the sheet metal blank 10 before rolling in side view, ie in profile, in greatly exaggerated representation. Here it can be seen that the board 10 before the rolling process has a uniform thickness over the length.

Figure 3c ) shows the board 10 ₂ after the rolling process according to the method step A2 FIG. 1 or B2 after FIG. 2 , In Figure 3c ) it can be seen that the board has received 10 ₂ by rolling a variable thickness profile over the length. As a result of the lower flow resistances, the more heated regions 13, 16 are more strongly rolled out than the colder regions 12, 15 due to the different temperature zones 11-16 produced before rolling. The thickness profile of the circuit board 10 shown schematically in FIG Length.

The FIGS. 4a ) and b), which will be described together below, show a sheet metal blank 10 in a further possible embodiment after the partial change of the temperature and before the rolling process according to FIG FIG. 4a ) or after rolling according to FIG. 4b ). The distribution of the different temperature ranges largely corresponds to that according to FIG. 3 , so that reference is made to the above description in terms of similarities. A special feature of the present embodiment is that the region 15 has a temperature gradient transverse to the rolling direction R of the board 10. That is, the temperature T ₁₅ 'is about 600 ° C on one side 18 and about 800 ° C on the opposite other side 19. The remaining areas 11, 12, 13, 14 and 16 have transversely to the rolling direction R largely uniform temperatures.

Characterized in that the temperature in the region 15 is variable transversely to the rolling direction, the board is unevenly rolled off. It is in FIG. 4b ) recognizable that the board 10 ₂ has undergone a shape change in the longitudinal direction after rolling. In this case, the board 10 ₂ on the side 18 of the region 15, which is more strongly cooled to 600 ° C. was less severely rolled than on the opposite side 19, which has been cooled to only 800 ° C. Thus, a total, in plan view of the board 10, a kink in this section 15 _first The thickness profile along the length at the side 18, the region 15 has been cooled more, is in Figure 4c ). This corresponds essentially to the profile according to Figure 3c ), wherein in the present case in particular the transition regions 22 are made thinner.

By generating different temperature ranges T ₁₅ also transversely to the rolling direction R a maximum degree of flexibility is achieved with respect to the thickness profile. Advantageously, the sheet metal blanks 10 to be produced can be individually adapted to the desired thickness profile for the subsequent end product. The benefit of relating to the FIGS. 1 and 2 described method according to the invention and the associated devices is that finished mold cuts can be made within a short process chain with high efficiency. In particular, the combination of the process control with partial temperature change according to method step A1 or B1 of the sheet metal blank 10 before rolling, subsequent normalization and final hot forming is particularly favorable, since the temperature level in the metal sheet overall remains relatively high over the entire process chain, in particular over 400 ° C to 500 ° C, and thus the input of energy for manufacturing is low. In this way, the shape cutting boards can be produced with a short process chain and the associated high efficiency.

LIST OF REFERENCE NUMBERS

10

circuit board

11-16

Area / section

21-25

Transition area / transition section

30

Temperature changing tool

40

rolling tool

41

roll

42

roll

50

heater

60

forming tool

A

process sequence

B

process sequence

D

thickness

R

rolling direction

T

temperature

Claims (6)

1. Process of producing metal blanks with different thicknesses from a metallic material, comprising the process stages:

   producing blanks (10) from a strip material;

   regionally changing the temperature (T) of the blanks (10), wherein a plurality of regions (11-16) with different temperatures (T₁₁-T₁₆) are generated in the metal blanks (10);

   rolling the regionally temperature changed blanks (10) in a rolling tool (40) with a roll gap setting, wherein the roll gap setting is kept constant during rolling of the blanks (10), wherein, due to the regions with different temperatures (T₁₁-T₁₆), portions (11 - 16) are produced in the blanks (10) with different thicknesses (D₁₁ - D₁₆),

   characterised in that the blanks (10) are heated after having been rolled, and, after having been heated, are hot-formed in a forming tool,

   wherein the blanks (10), with the regions (11, 16) having the highest temperatures (T₁₁; T₁₆) after the regional temperature change, always have a temperature of more than 500°C for steel during the subsequent steps of rolling and heat treating up to being inserted into the forming tool.
2. Process according to claim 1,
   characterised in
   that of the regions (11 - 16) with different temperatures (T₁₁-T₁₆), at least one region (11 - 16) with a constant temperature (T₁₁-T₁₆) and/or at least one region (15') with a variable temperature (T₁₅') is produced transversely to the rolling direction (R).
3. Process according to claim 1 or 2,
   characterised in
   that regionally changing the temperature is effected by heating or cooling of at least one region (11 - 16) of the blank (10), in particular by means of at least one punch (30) which is brought into contact with the blank (10), so that the blank (10) at least substantially assumes the temperature of the punch (30).
4. Process according to claim 1 or 2,
   characterised in
   that regionally changing the temperature is effected by induction-heating of at least one region (11 - 16) of the blank (10), wherein the blanks (10) are passed through current-conducting rolls, wherein the regions (11-16) with different temperatures (T₁₁-T₁₆) are produced by varying the power of the current-conducting rolls while the blanks (10) are passed through.
5. Process according to claims 1 to 3,
   characterised in
   that regionally changing the temperature is effected by cooling at least one region (11-16) of the blank (10), wherein the blanks (10) are heated homogenously to a first temperature prior to being regionally cooled.
6. Process according to any one of claims 1 to 5,
   characterised in
   that the metal blanks (10), with the regions (11,16) having the highest temperatures (T₁₁; T₁₆) after the regional temperature change, always comprise a temperature (T₁₁; T₁₆) of more than 600°C during the subsequent process stages of rolling and heat treatment up to the stage of being inserted into the forming tool.

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