EP3072980B1 - Method and device for producing a partially cured moulded part - Google Patents

Description

The invention relates to a method and a device for producing a partially cured molded part, in particular for use as a structural component of a motor vehicle.

From the DE 10 2006 015 666 A1 For example, a method of manufacturing a metal mold component by hot working with simultaneous trimming operation is known. For this purpose, a combination tool is used with an upper tool attached to a press ram, a die mounted on a press table via force elements and with a cutting tool fixed on a cutting punch. The cutting punch is arranged on the edge or in a recess of the die. To produce a press-hardened, trimmed component, a suitably dimensioned semi-finished product is heated and inserted into the combination tool. In the tool, the semi-finished product is converted to the desired shape in the hot state and cooled defined. The trimming of the component edges takes place in the combination tool immediately following the molding, whereby the residual heat still present from the hot forming is utilized. The trimming should be done at a temperature between 400 ° C and 700 ° C.

From the DE 10 2011 120 725 A1 For example, a method and apparatus for hot working and partially curing a component are known. The apparatus comprises a hot forming tool having a first tool part with two segments and an opposite second tool part, between which the component is formed becomes. In the first segment, an inductor is accommodated, which can bring energy during compression in a first portion of the component. The energy input leads to a slowing down of the cooling rate in the first part, so that no hardening occurs here.

From the DE 10 2005 032 113 B3 For example, a method and apparatus for thermoforming and partially curing a component between two mold halves in a press is known. The tool halves are each divided into several segments, which are separated by a heat insulation. The two segments can be heated or cooled by a temperature control, so that different temperatures and thus cooling curves are adjustable in different areas of the component.

From the EP 1 715 066 A1 a device for forming and press hardening of metal sheets is known. In a forming tool heating elements are integrated to heat the metal sheet in the forming area and partially influence by targeted temperature control of the material structure. The heating elements are thermally insulated from the adjacent walls of the forming tool by an insulating layer.

Moldings, in particular as structural components of motor vehicles, should have different, partially contradictory technical properties. For example, moldings in subregions should have a high hardness or strength and low ductility, while in other subregions, in turn, a low hardness or strength and a high ductility are desired. From this, the requirement is derived to produce molded parts near the final contour and specifically with the desired material properties.

The present invention is therefore based on the object to propose a process for the preparation of partially cured moldings, which can be carried out easily and quickly and with which the moldings can produce near net shape. The object is also to propose a corresponding device, which allows the production of hardened moldings with high accuracy and short cycle times.

A solution is a method for producing a partially cured metallic molding, comprising the steps of: heating a semifinished product of a hardenable thermoformable steel sheet to a hardening temperature; Hot working the heated semi-finished product into a three-dimensional molded part in a combined hot-forming cutting device, the combined hot-forming cutting device having an upper tool part and a lower tool part which are closed to hot-work the semi-finished product; Trimming the molding in the combined hot stamping-cutting apparatus; Press-hardening the molded article in the hot-forming cutting device into a hardened molded article, wherein at least one of the upper tool part and the lower tool part has a first tool portion that contacts a first portion of the molded article during hot working and press hardening is cooled, so that the first portion is cured by rapid cooling, and, wherein at least one of the upper tool part and the lower tool part has a second tool portion which comes into contact with a second portion of the semifinished product during hot working and press hardening, wherein the second Tool section is heated, so that a second portion of the molding is produced by heating with a higher ductility and lower strength than the first portion, wherein it is further provided that the second tool portion is temporarily or permanently cooled to overheat avoid; wherein the trimming of the molding takes place at least in one of the first subregion and the second subregion.

An advantage of the method is that mold parts can be hot-formed, trimmed and press-hardened in one process step. Post-processing by a separate pruning in a separate trimming tool can be omitted. Unwanted changes in the form and structure of the moldings can be minimized. It is produced in a simple manner a near-net shape molding with the desired material properties. By at least one of the first and second sub-areas is meant that trimming in the first subarea and / or in the second subarea.

The heating to hardening temperature can be carried out such that the entire output member is heated or partially only the partial areas to be cured. By hardening temperature in this context is meant a temperature of the semifinished product or component which is at least necessary in order subsequently to harden the component by rapid cooling (quenching). For austenitic steels, for example, the minimum hardening temperature would be the austenitizing temperature. The rapid cooling (quenching) takes place in particular below the critical cooling rate, so that it comes to the formation of a martensitic hardness structure.

The trimming of the molded part can take place at least in a second partial area, which is heated and thus softer than the first partial area to be hardened. This has the advantage that the cutting operation can be carried out more easily and the cutting tool is subject to only little wear. With the formulation, at least one first or second subarea is to be encompassed within the scope of this disclosure in particular that the molded part can each have one or more first and second subregions. It is envisaged that at least one of the softer second subregions will be trimmed, wherein it is not excluded that further second subregions may remain untrimmed and / or that one or more first subregions may be partially or completely trimmed prior to press hardening. If in the present case one or the first subarea or one or the second subarea is mentioned, this should always be meant in the sense of at least one of the respective subareas.

As well as semifinished starting material for the molded part to be produced in particular a board made of sheet steel can be used. The board may have a uniform or variable sheet thickness over the length and / or width. The production of a board with variable sheet thickness can for example be done by flexible rolling of strip material and subsequent cutting of the board from the flexibly rolled strip material, or by welding together of partial boards with different sheet thickness.

According to a preferred embodiment, the semifinished product or component is heated during the hot forming in a peripheral second portion. That is, at least one of the softer second subregions forms an edge zone of the molded part, which is trimmed in the context of the combined hot forming, cutting and pressing hardening process. In this way, the molding receives its final contour, so that a separate trimming process can be omitted. The second subregion can optionally be flown with air before, during and / or after the hot forming. This applies alternatively or in addition to the first part to be cured, which can be at least partially flowed with air. In the first partial area to be hardened, the short-term flow of air has the function of preventing excessive wall thickness reduction due to high temperatures.

The combined hot-forming cutting device has at least one upper tool part and at least one lower tool part, which are closed for hot forming of the component, wherein the trimming takes place in particular during or after the closing of the tool parts. The closing of the tool parts can take place in that only one of the two tool parts is moved while the other is stationary, or in that both tool parts are moved towards each other. For hot forming, the semi-finished product, which is heated to hardening temperature at least in some areas, is inserted between the upper and lower tool parts. When the two tool parts are pressed together, the contour of the molding tool is transferred to the semifinished product, which is thus shaped into the molded part. If the first partial areas to be cured are to be trimmed, they are preferably trimmed before the tool parts are completely closed. The second subsections with higher ductility can in principle be trimmed at any time, that is before, during and / or after complete closure. Due to the complete closing, which corresponds to the end of the press stroke, they come into planar contact with the molded part, so that the first part area is rapidly cooled and thus hardened. The second portion is heated during the forming and pressing in the tool. For this purpose, at least one of the tool parts has a corresponding tempering device, with which the tool can be heated in the coming into contact with the second portion portion.

After closing the tool parts, the molded part can be kept in the second partial area at a defined temperature, which is in particular between 300 ° C and 600 ° C. The holding time of the molded part between the closed tool parts can be between 0.5 seconds to 360 seconds. At the end of the press stroke, that is, when the component is at least largely transformed, the second portion is trimmed. The molding now has its final contour and can be removed from the device after reopening the tool parts. After opening the tool parts, the second portion of the molding can be flown with air. In order to avoid overheating of the tempered tool part, it is provided as a further process step that one or more of the tool parts is cooled temporarily or permanently, that is before, during and / or after the hot forming. This applies at least to a heated second tool section, but can also apply to a first tool section.

The above object is further achieved by a hot-forming cutting apparatus for producing a metallic molding, comprising: an upper tool part; a lower tool part; wherein the upper tool part and the lower tool part can be closed in order to transform a semi-finished product inserted between the upper tool part and the lower tool part into a shaped part; wherein at least one of the upper and lower tool parts has a first tool portion which comes into contact with a first portion of the semifinished product when closing, wherein the first tool portion comprises a first tempering device with which the first tool portion is adjustable to a first temperature; wherein at least one of the upper and lower tool parts has a second tool portion which comes into contact with a second portion of the semifinished product upon closing; wherein the second tool portion comprises a second tempering device with which the second tool portion is adjustable to a second temperature which is higher than the first temperature of the first tool portion, wherein the second tool portion further comprises a channel arrangement for cooling, which can be flowed through by a fluid; wherein at least one of the upper and lower tool parts in at least one of the first tool portion and the second tool portion at least one Cutting tool which is designed to trim the molding in the respective first and second sub-area.

With the mentioned device, the same advantages already mentioned in connection with the method result. In particular, with the device moldings can be hot-formed, trimmed and partially hardened in one step. The device enables the production of a near net shape molded part with the desired material properties. It is understood that the method and apparatus belong together insofar as all procedural features are transferable to the apparatus and vice versa, all device-related features on the method. A molded part produced using the device or the method is particularly suitable as a structural component for use in a vehicle body or a running gear of a motor vehicle.

It is provided that the first temperature control device is designed to cool the first tool section so fast that the molded part is hardened in the first partial region. For this purpose, the first tempering device may have a cooling channel arrangement through which a cooling medium can flow. The cooling channels extend through the tool in such a way that the tool surface coming into contact with the first subregion is cooled. As a cooling medium, for example, water can be used. It is further provided that the second tempering device is configured to heat the second tool section, so that the molded part in the second partial area receives a higher ductility than in the first partial area. As tempering heater cartridges can be used, which are arranged in corresponding cavities of the second tool section. The heating cartridges are arranged in the areas of the tool in which the component is to receive a higher ductility by heating. The heat of the heating cartridges is transferred to the tool and from there to the component.

In addition to the tempering device for heating the tool, a channel arrangement for cooling, which can be flowed through by a fluid, is also provided in the second tool section. This can prevent overheating of the tool become. It is understood that such a channel arrangement can also be provided in the first tool section. The first and the second tool section each have at least one molding surface which comes into contact with the component during closing, wherein at least a part number of channels of the channel arrangement can be designed such that they open into one of the molding surfaces. In this case, air is preferably used as the fluid which can be blown to the component. As a result, the molded part is cooled, wherein the air also has a cooling effect for the molded part at the same time. It is also conceivable embodiment in which the cooling channels have no mouth to the molding surface, but only in the interior of the tool at a distance from the surface. In this case, the cooling channels can be arranged in particular at a deeper distance from the tool surface than parts of the tempering device for heating the tool.

In one embodiment, a second tool portion and a first tool portion may be separated by an insulating material or a gap. In the latter case, the gap acts as an insulation between the two tool sections, so that they do not influence each other in an undesirable manner with regard to the temperature to be set. Alternatively or in addition, a first and a second tool section can connect directly, that is, without a gap, to one another.

A cutting tool for trimming the formed part may in principle be arranged at any desired point of the hot forming cutting device, in which a trimming of the molded part is required. In particular, a cutting tool can be arranged in an edge region of the first and / or second tool section, so that a protruding edge of the molding is cut off. In this way, the moldings can be produced close to the final contour in the combined hot-forming cutting device in an advantageous manner. It goes without saying in that a further cutting tool can also be arranged in a central region of the molded part to be produced, that is to say at a distance from the edge, for example to produce passage openings or bores there.

In particular, it is contemplated that a cutting tool of the hot stamping-cutting apparatus comprises a cutting punch connected to one of the upper and lower tool parts, and a cutting die connected to the other of the upper and lower tool parts and an exemption for board waste. The hot forming cutting device is designed with respect to the movement mechanism for the hot forming and cutting process so that the cutting takes place before the press-hardening of the molded part. For this purpose, it is provided that the cutting tool performs the cut on the molding before the molding is cooled by full surface contact with the cooled tool parts. By this configuration, a costly and energy-intensive trimming of the cured component can be omitted.

Figur 1

eine erfindungsgemäße Warmumform-Schneide-Vorrichtung zur Herstellung eines metallischen Formteils in einer ersten Ausführungsform;

Figur 2

ein Detail der Warmumform-Schneide-Vorrichtung aus Figur 1 in vergrößerter Darstellung;

Figur 3

ein Ausgangsbauteil in Draufsicht;

Figur 4

ein aus dem Ausgangsbauteil nach Figur 4 erfindungsgemäß hergestelltes Formteil als B-Säule;

Figur 5

ein erfindungsgemäßes Verfahren zur Herstellung eines metallischen Formteils;

Figur 6

schematisch eine erfindungsgemäße Warmumform-Schneide-Vorrichtung zur Herstellung eines metallischen Formteils in einer zweiten Ausführungsform;

Figur 7

schematisch eine erfindungsgemäße Warmumform-Schneide-Vorrichtung zur Herstellung eines metallischen Formteils in einer abgewandelten Ausführungsform.

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

FIG. 1

a hot-forming cutting device according to the invention for producing a metallic molding in a first embodiment;

FIG. 2

a detail of the hot forming cutting device FIG. 1 in an enlarged view;

FIG. 3

an output member in plan view;

FIG. 4

one from the starting component after FIG. 4 Molded part produced according to the invention as B-pillar;

FIG. 5

an inventive method for producing a metallic molding;

FIG. 6

schematically a hot-forming cutting device according to the invention for producing a metallic molded part in a second embodiment;

FIG. 7

schematically a hot-forming cutting device according to the invention for producing a metallic molded part in a modified embodiment.

The FIGS. 1 to 7 will be described together below.

In the FIGS. 1 and 2 a hot forming cutting device 2 is shown in cross section, which serves for the production of a three-dimensional metallic molded part. Starting material for the production of the three-dimensional molded part 20 is a semi-finished product 19, in particular a sheet steel plate, which can also be referred to as a shaped cut or flat component.

The semifinished product 19 can be made of strip material made of sheet steel. The strip material can be produced by rolling after prior heating (hot strip) and / or the strip material can be cold-rolled, the last reduction in thickness being effected by rolling without prior heating (cold strip). The semifinished product to be formed may have a uniform sheet thickness over the length or width of the component. It is also possible that the semifinished product has regions of different thickness. These can be produced in several ways, for example by means of flexible rolling (Tailor Rolled Blanks), strip profile rolls or by welding individual metal sheets with different sheet thickness (Tailor Welded Blanks).

In flexible rolling, strip material having a substantially uniform sheet thickness is rolled out over the length by varying the roll gap during the process into strip material of variable sheet thickness. The sections of different thickness produced by the flexible rolling extend transversely to the longitudinal direction or to the rolling direction of the strip material. In strip rolling, sheet material, that is, strip material or individual sheet elements, is rolled with substantially uniform thickness through a rolled section into sheet material of variable thickness across the width of the material. The sections of different thickness produced by strip profile rollers extend in the longitudinal direction of the sheet material. In band profile rolling, which is also referred to as roll forming, individual areas of the sheet material are stretched outwards.

With the hot-forming cutting device 2 can be processed arbitrarily manufactured boards 19 for molding 20. The specific design of the hot-forming cutting device 2 is based on the contour of the molded part to be produced. The device 2 shown here is used to produce a molding for the B-pillar of a motor vehicle. A shaped section 19 for producing the B-pillar is shown in plan view in FIG FIG. 3 shown. The three-dimensional B-pillar 20 produced from the flat shaped section 19 is shown in FIG FIG. 4 shown. The B-pillar 20 has an approximately hat-shaped profile when viewed in cross-section.

The hot-forming cutting device 2 shown for producing the B-pillar 20 has a plurality of upper tool parts 3, 4, 5, and a plurality of lower tool parts 6, 7, 8, between which the flat semi-finished product is inserted and by relative movement of the upper tool parts 3, 4, 5 in the direction of tool lower parts 6, 7, 8 is formed into a three-dimensional molded part. The lower tool parts 6, 7, 8 are mounted on support elements 9, 10.

The hot-forming cutting device 2 further comprises a plurality of cutting tools 11, 12, which are designed to trim the molded part 20. The cutting tools 11, 12 each comprise a cutting edge 31, 32 and a counter-blade 33, 34, which cooperate in closing the device to cut off a projecting part of the molding. The cutting, respectively counter cutting, which can also be referred to as a punch and cutting die, are preferably made of a hardened material. It can be seen that the sheaths 31, 33 are each arranged in lateral recesses of the tool lower part 7 and are firmly connected thereto. This is done via, for example, means Screw connections, as the holes 22 in the tool part 7 reveal, with other common types of connection are also conceivable.

The upper tool parts 3, 4, 5 and the lower tool parts 6, 7, 8 each have near-surface tool sections 13, 14, 15; 16, 17, 18, which come into contact with the semifinished product when closing the tool. Due to the closing movement of the upper tool parts relative to the lower tool parts, the planar board arranged therebetween is shaped into the three-dimensional molded part 20. The cutting tools 11, 12 are arranged in relation to the forming tool sections so that the trimming occurs when the semi-finished product 19 is already largely converted to the molding 20, but before the device 2 is completely closed, that is before the molding 20 in full surface contact is press-hardened with the tool parts.

There are tempering devices 23, 24, 25; 26, 27, 28 provided to temper the near-surface tool sections, the tempering may be a cooling and / or heating. It is envisaged that at least one of the upper and lower tool parts 3, 4, 5; 6, 7, 8 has two different tempering device such that a first tempering of the tool part for cooling and a second tempering for heating the tool part is configured.

This is explained by way of example at the upper tool part 3, whose tempering device 23 has a first tempering device 23A, which serves to selectively cool the associated first tool section 13A to a first temperature T1, and has a second tempering device 23B, which heats up the associated second tool section 13B a second temperature T2 is higher than the first temperature T1. The first temperature T1 for the first tool section 13A is adjusted so that the molding 20 is hardened in this area during pressing between the upper tool parts 3, 4, 5 and the lower tool parts 6, 7, 8. As a result of the first tool section 13A cooled to the first temperature T1, the component 19 becomes such starting from the hardening temperature Cooled quickly with critical cooling rate that a material structure with high hardness or high strength arises.

On the other hand, the second tool portion 13B is heated to the second temperature T2, which may be, for example, between 300 ° C and 600 ° C. By heating the second tool portion 13B, the molding 20 obtains higher ductility and lower strength in this area than in the hardened first area. The lower tool parts 6, 7, 8 are designed according to the desired structural properties of the molded part 20 opposite to the upper tool parts 3, 4, 5. That is, the first tool portion 17A of the lower tool part 7 facing the cooled first tool portion 13A of the upper tool part 3 is also cooled, while the second tool portion 17B of the lower tool part 7 facing the heated second tool portion 13B of the upper tool part 3 is also heated.

The first tempering devices 23A, 27A of the upper tool part 3 and the lower tool part 7 each have a cooling channel arrangement with a plurality of cooling channels through which a cooling medium can flow. The cooling channels extend in such a way through the upper die part 3 or the lower die part 7 that the tool surface coming into contact with the part region 21B of the semifinished product or component 19 that is to be cooled is cooled. As a cooling medium, for example, water can be used.

As second tempering means 23B, 27B, which serve to heat the second tool sections 13B, 17B, heating cartridges can be used, which are inserted into corresponding cavities of the second tool sections. In this case, the heat of the heating cartridges is transferred to the second tool sections 13B, 17B and from these to the intermediate semifinished product or component 19.

It can be seen that the cutting tool 11 is arranged in the region of the heated second tool sections 23B, 27B of the upper and lower tool parts 3, 7 is. The trimming of the molded part 20 thus takes place in a partial area 21B, which has a higher ductility due to the heating than in the cooled partial areas 21A. This has the advantage that the cutting tool 11, 12 is subject to only a slight wear in this heated section. It is understood, however, that one or more further cutting tools can also be provided in tool sections which are designed for press hardening of the molded part, which however is not critical for the wear of the cutting tool as the trimming during the press stroke in time before the complete flat concerns of the tool parts. 3 4, 5; 6, 7, 8 takes place on the component and thus before the curing of the molded part.

The holding period of the molding 20 between the fully closed tool parts 3, 4, 5; 6, 7, 8 can be between 0.5 seconds to 360 seconds. After the holding period, the molded part 20 has its final contour and the desired structure and, after reopening the tool parts 3, 4, 5; 6, 7, 8 are removed from the device.

A method according to the invention for producing a partially hardened metallic molded part 20 with a hardened first partial area 21A and a ductile second partial area 21B thus comprises the following steps, as in FIG FIG. 5 schematically shown: heating of the semi-finished product 19, which is made of a curable thermoformable steel sheet, at least in the first portion 21B to a hardening temperature (step S10). This can be done, for example, inductively or in an oven. Subsequently, the semi-finished product 19 in the combined hot-forming cutting device 2 is hot-formed into the three-dimensional molded part 20 (step S20); If the semifinished product is at least largely converted to the molded part 20, the molded part 20 is cut in the hot-forming cutting device 2 (step S30). In a further method step (S40), the molded part 20 is press-hardened in the hot-forming cutting device 2 such that a first partial region 21A is hardened by rapid cooling, and that a second partial region 21B of the molded article 20 is heated by a higher ductility and lower strength is generated than the first portion 21A. Subsequently, the component 19 is cut in the hot forming cutting device 2 at least in the second portion 21B of the cutting tool 11, which preferably takes place in time before curing. To one

To avoid overheating of the heated tool parts, can be provided as an additional process step that they are cooled temporarily or permanently.

A B-pillar as a molded article 20 produced in the hot-forming cutter 2 according to the method is shown in FIG FIG. 4 shown. This has regions 21B with increased ductility and low strength, which are darkened in the drawing, and a hardened region 21A with increased strength and low ductility. At least parts of the areas 21B are hot cut. It is understood that this embodiment is only an example and that the specific embodiment of the molded part 20 depends on the technical requirements placed on it.

FIG. 6 shows a hot-forming cutting device 2 according to the invention in a modified embodiment. This corresponds largely to the embodiment according to the FIGS. 1 and 2 , so that reference is made to the above description in terms of similarities. The same or corresponding details are provided with the same reference numerals as in the FIGS. 1 and 2 ,

A difference of the present embodiment is that only one upper tool part 3 and a lower tool part 6 are provided. The upper tool part 3 and the lower tool part 6 each have a first tool section 13A, 17A which is cooled for press-hardening of the molded part 20, wherein the cooling channels are not shown for the sake of simplicity. Furthermore, the upper tool part 3 and the lower tool part 6 each have a second tool section 13B, 17B, which are each equipped with tempering devices 23B, 27B for heating the component 19. In the present case, the temperature control devices 23B, 27B are designed in the form of heating plates whose temperature T2 can be set via corresponding temperature regulators. The heated second tool sections 13B, 17B are insulated from the cooled first tool sections 13A, 17A by insulation material 37, 38 or air gaps.

Furthermore, a cutting tool 11 can be seen in the region of the heated second tool sections 13B, 17B of the upper and lower tool parts 3, 7. The

Cutting edge 31 is fixedly connected to the upper tool part 3, for example by a screw, and the counter-blade 33 is associated with the lower tool part 7 or fixedly connected. In the counter cutting edge 33 laterally adjacent edge region of the tool part 7, a recess 35 is provided which serves as an exemption for the cut edge of the component 19. In addition, a second cutting tool 12 in the edge region of the cooled first tool sections 13A, 17A of the upper and lower tool part 3, 7 can be seen. In this case, the cutting edge 32 is fixedly connected to the upper tool part 3, while the counter-blade 34 is connected to the lower tool part 7. Laterally adjacent to the counter-blade 34, a recess 36 is provided as an exemption for board waste.

Thus, in the present embodiment, trimming of the molding 20 is performed both in a tool section 13A, 17A cooled to harden the molding and in a tool section 13B, 17B heated to produce ductility.

The FIG. 7 shows a hot-forming cutting device 2 according to the invention in a modified further embodiment. This corresponds largely to the embodiment according to FIG. 6 , or the FIGS. 1 and 2 , so that reference is made to the above description in terms of similarities. The same or corresponding details are provided with the same reference numerals FIG. 6 , respectively the FIGS. 1 and 2 ,

A special feature of the present embodiment is that the second tool sections 13B, 17B are each equipped with a cooling device. The cooling device comprises a channel arrangement 39, 40 with a plurality of channels which extend through the second tool sections 13B, 17B and open into the shaping surface. In this respect, the cooling device has two functions, namely the cooling of the second tool sections 13 B, 17 B, in order to avoid overheating, as well as the blowing of the component in order to cool it after the reopening of the device 2. Air is used as the cooling medium.

Overall, the devices according to the invention and the method carried out with them offer as an advantage that moldings can be hot-formed, trimmed and press-hardened in one process step. It is produced a near-net shape molding with the desired material properties.

LIST OF REFERENCE NUMBERS

2

Hot-forming cutting device

3

upper tool part

4

upper tool part

5

upper tool part

6

lower tool part

7

lower tool part

8th

lower tool part

9

support element

10

support element

11

cutting tool

12

cutting tool

13, 13A, 13B

tool section

14

tool section

15

tool section

16

tool section

17, 17A, 17B

tool section

18

tool section

19

Workpiece

20

molding

21A

first subarea

21B

second subarea

22

drilling

23, 23A, 23B

tempering

24

tempering

25

tempering

26

tempering

27

tempering

28

tempering

31

cutting edge

32

cutting edge

33

against cutting

34

against cutting

35

recess

36

recess

37

insulation material

38

insulation material

39

channel arrangement

40

channel arrangement

S

step

T

temperature

Claims (14)

1. A process of producing a partially hardened metallic formed part, comprising the following steps:

   heating (S10) a semi-finished product (19) of hardenable hotformable steel sheet to a hardening temperature;

   hot-forming (S20) the heated semi-finished product (19) in a combined hot-forming cutting device (2) into a three-dimensional formed part (20), wherein the combined hot-forming cutting device (2) comprises an upper tool part (3, 4, 5) and a lower tool part (6, 7, 8) which are closed for hot-forming the semi-finished product (19);

   cutting (S30) the formed part (20) in the hot-forming cutting device (2);

   press-hardening (S40) the formed part (20) in the hot-forming cutting device (2) into a hardened formed part (20), wherein at least one of the upper tool part (3, 4, 5) and the lower tool part (6, 7, 8) comprises a first tool portion (13A, 27A) which, during the hot-forming (S20) and press-hardening (S40), comes into contact a first partial region (21A) of the formed part (20), wherein the first tool portion (13A, 27A) is cooled such that the first partial region (21A) is hardened by rapid cooling, and wherein at least one of the upper tool part (3, 4, 5) and of the lower tool part (6, 7, 8) comprises a second tool portion (13B, 27B) which, during the hot-forming (S20) and press-hardening (S40) comes into contact with a second partial region (21B) of the semi-finished product (19), wherein the second tool portion (13B, 27B) is being heated such that the second partial region (21B) of the formed part (20) is heat-treated so as to obtain a greater ductility and a lower strength than the first partial region (21A), wherein it is further provided that the second tool portion (13B, 27B) is temporarily or permanently cooled to avoid an overheating;

   wherein the step of cutting (S30) the formed part (20) takes place in at least one of the first partial region (21A) and of the second partial region (21B).
2. Process according to claim 1,
   characterised in
   that the cutting (S30) takes place while the tool part (3, 4, 5; 6, 7, 8) is being closed and prior to the press-hardening (40) .
3. Process according to claim 1 or 2,
   characterised in
   that, after the tool parts (3, 4, 5; 6, 7, 8) have been closed, the semi-finished product (19) is held at a temperature (T2) between 300°C and 600°C in the second partial region.
4. Process according to any one of claims 1 to 3,
   characterised in
   that the tool parts (3,4, 5; 6, 7, 8) are kept closed for a period of 0.5 seconds to 360 seconds.
5. Process according to any one of claims 1 to 4,
   characterised in
   that the first tool portion (13A, 27A) is cooled prior to, during and/or after the hot-forming.
6. Process according to any one of claims 1 to 5,
   characterised in
   that at least one of the first partial region (21A) and of the second partial region (21B) of the formed part (20) is subjected to an air flow prior to, during and/or after the tool parts (3, 4, 5; 6, 7, 8) are being opened.
7. A hot-forming cutting device (2) for producing a metallic formed part, comprising:

   an upper tool part (3, 4, 5),

   a lower tool part (6, 7, 8),

   wherein the upper tool part (3, 4, 5) and the lower tool part (6, 7, 8) can be closed for forming a semi-finished product (19) inserted between the upper tool part (3, 4, 5) and the lower tool part (6, 7, 8) into a formed part (20),

   wherein at least one of the upper tool part (3, 4, 5) and of the lower tool part (6, 7, 8) comprises a first tool portion (13A, 17) which, during closing, comes into contact with a first partial region (21A) of the semi-finished product (19), wherein the first tool portion (13A, 17A) comprises a first tempering device (23A, 27A) by which the first tool portion (13A, 17A) can be set to a first temperature (T1),

   wherein at least one of the upper tool part (3, 4, 5) and of the lower tool part (6, 7, 8) comprises a second tool portion (13B, 17B) which, during closing, comes into contact with a second partial region (21B) of the semi-finished product (19), wherein the second tool portion (13B, 17B) comprises a second tempering device (23B, 27B) by which the second tool portion (13B, 17B) can be set to a second temperature (T2) which is higher than the first temperature (T1) of the first tool portion (13A, 17A), wherein the second tool portion (13B, 17B) comprises a channel arrangement (39, 40) for cooling, through which a fluid can flow,

   wherein at least one of the upper tool part (3, 4, 5) and the lower tool part (6, 7, 8), in at least one of the first tool portion (13A, 17A) and of the second tool portion (13B, 17B), comprises at least one cutting tool (11, 12) which is designed to cut the formed part.
8. Hot-forming cutting device (2) according to claim 7, characterised in
   that the first tempering device (23A, 27A) is designed for rapidly cooling the first tool portion (13A, 17B) such that the formed part (20) is hardened in the first partial region (21A), and
   that the second tempering device (23B, 27A) is designed for heating the second tool portion (13B, 17B) such that the formed part (20) obtains a greater ductility in the second partial region (21B) than in the first partial region (21A).
9. Hot-forming cutting device (2) according to claim 7 or claim 8,
   characterised in
   that the first tempering device (23A, 27A) comprises a cooling channel arrangement though which a cooling medium can flow.
10. Hot-forming cutting device (2) according to any one of claims 7 to 9,
    characterised in
    that the second tempering device (23B, 27B) comprises a plurality of heating cartridges which are received in cavities of the second tool portion (13B, 17B).
11. Hot-forming cutting device (2) according to any one of claims 7 to 10,
    characterised in
    that the first tool portion (13A, 17A) and the second tool portion (13B, 17B) each comprise a forming face which, during the closing, comes into contact with the semi-finished product (19), wherein at least a partial number of channels of the channel arrangement (39, 40) ends in the forming face, so that the air emerging from the channels can be blown against the semi-finished product.
12. Hot-forming cutting device (2) according to any one of claims 7 to 11,
    characterised in
    that the second tool portion (13B, 17B) and the first tool portion (13A, 17A) are separated from one another by an insulating material (37, 38).
13. Hot-forming cutting device (2) according to any one of claims 7 to 12,
    characterised in
    that the cutting tool (11, 12) is arranged in an edge region of the first tool portion (13A, 17A) and the second tool portion (13B, 17B) respectively and extends at least over a partial circumferential portion of the hot-forming cutting device (2).
14. Hot-forming cutting device (2) according to any one of claims 7 to 13,
    characterised in
    that the cutting tool (2) comprises a cutting punch (31) which is connected to one of the upper and lower tool parts (3, 4, 5; 6, 7, 8), and a cutting die (33) which is connected to the other one of the upper and lower tool parts (6, 7, 8; 3, 4, 5), as well as a recess (35, 36) for sheet blank waste.

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