DE102011116885A1 - Device for hot-forming and press-hardening with coated sheet metal material, has lubricant application unit that applies lubricant on tool effective areas or presses lubricant film between sheet metal material and tool effective area - Google Patents

Abstract

The device comprises a tool having two tool portions that are relatively moved to each other to open and close of the tool. The tool effective areas of the tool portions are directly contacted with the coated sheet metal material. A lubricant application unit is provided for applying (Va) the lubricant on one of the tool effective areas or for pressing (VI) a lubricant film between the coated sheet metal material and tool effective area, when the tool is opened. The coated sheet metal material is coated with anti-corrosive coating of zinc or aluminum. An independent claim is included for method for hot-forming and press-hardening with coated sheet metal material.

Description

The invention relates to a device for hot forming and in particular for press hardening or form hardening of a sheet metal material coated with a metallic corrosion protection coating. The invention further relates to a method for hot forming and in particular for press hardening a sheet metal material coated with a metallic anti-corrosion coating.

By hot forming is meant here the forming of a metallic sheet material and in particular a steel sheet material in a hot forming tool, which takes place above the recrystallization temperature (which may be up to several hundred degrees Celsius), to which the sheet metal material to be formed is heated to an appropriate temperature prior to forming. The hot forming tool may also be formed with a heater. In this way, z. B. even with high-strength steel sheet materials (this includes in particular high and high strength steel sheet materials) achieve high degrees of deformation with relatively low forming forces, the produced sheet metal parts have a good to very good dimensional stability.

As a special variant of the hot forming, the press hardening can be understood. In press-hardening, the previously heated sheet material and in particular steel sheet material is quasi-simultaneously formed in a cooled press-hardening tool and cooled or form-calibrated and cooled, in order to specifically increase its strength and / or hardness. The sheet metal part produced thus has higher-strength properties, which, however, have emerged only through the press-hardening.

The hot forming and in particular the press hardening of sheet materials and in particular steel sheet materials is mainly used in the manufacture of vehicle parts for motor vehicles application, because hereby relatively light and highly resilient sheet metal parts, such as. Body reinforcement parts and chassis parts can be produced.

It is known to use for the hot forming and in particular for press hardening sheet steel materials which are already provided with a metallic corrosion protection coating or with a metallic coating. From the DE 201 22 563 U1 For example, a sheet metal material coated with a metallic anticorrosive coating is known which is suitable for hot forming and in particular for press hardening. A suitable for hot forming and coated with a metallic anti-corrosion coating steel sheet material is also from the current DE 10 2010 024 664 A1 known, this steel sheet material has air-hardening properties, so that a press hardening for strength increase is not mandatory.

It is problematic that micro-cracks form in the metallic anticorrosive coating and / or at the border between the metallic anticorrosive coating and the steel sheet material or base material which can extend into the base material and which under certain conditions form the hot-forming and in particular press-hardening of such a steel sheet material Affect the function of the produced sheet metal part.

It is therefore an object of the present invention to show ways in which such microcracks can be avoided or at least substantially reduced.

This object is achieved by a device according to the invention with the features of claim 1. Furthermore, this object is achieved by a method according to the invention with the features of the independent claim. The respective dependent claims relate to preferred embodiments and further developments, wherein the respective features and / or feature combinations, as well as the preceding and following explanations, analogously apply to both subject matters of the invention.

The inventive device for hot forming and in particular for press hardening a (at least partially) coated with a metallic anti-corrosion coating sheet material comprises (at least) a tool with at least two tool parts (in particular an upper tool part or tool shell and a lower tool part or tool base), the opening and closing the tool are movable relative to each other and each having at least one directly with the coated sheet metal material coming into or reaching tool acting surface. According to the invention, this device also comprises at least one lubricant application device, with which at least one tool active surface at least partially a lubricant can be applied, which during subsequent hot forming or press hardening a lubricant film between the coated sheet metal material (or its metallic corrosion protection coating) and the forms relevant tool effective area. The tool is in particular a hot forming tool or a press hardening tool.

According to the invention, the lubricant is applied at least regionally or locally to at least one tool-effective area of the tool and in particular to the entire surface of one or all tool-active surfaces of the tool. The tool acting surfaces are understood to mean the surfaces of the tool that come into direct contact with the sheet metal material to be hot-formed or press-hardened. The following explanations are generally non-limiting in nature of a lubricant application to the tool effective surfaces.

The invention is based on the finding that the above-mentioned microcracks arise as a result of high mechanical stresses occurring during hot forming or press hardening in the metallic anticorrosive coating and / or at the boundary between the metallic anticorrosive coating and the sheet material and / or base material. or at the surface of the metallic anti-corrosion coating. By applying a lubricant to the tool-working surfaces of the tool, it is possible to avoid adhesions of the metallic corrosion-protection coating to the tool-active surfaces and resulting stick-slip effects, which can be the cause of these high mechanical stresses. As a result, microcracks can be avoided or at least reduced in terms of frequency and crack depth to a minimum.

The use of a lubricant for hot working or press hardening of a vitrified metallic anticorrosive coated sheet material, particularly a sheet steel material, is not known in the art from the prior art. So far, the lubrication is accomplished during a hot forming process or press hardening process by the metallic anti-corrosion coating itself, as in the DE 201 22 563 U1 (see paragraph [0024]) and in the DE 10 2010 024 664 A1 (see paragraph [0030]).

Incidentally, the lubricant used in accordance with the invention can also serve to achieve improved heat transfer between the tooling surfaces and the coated sheet metal material (or its metallic corrosion protection coating) during hot forming and in particular during press hardening, regardless of the direction in which the heat transfer takes place.

It is preferably provided that the lubricant is applied only locally and in particular only in those areas on the tool effective areas in which a high risk for the emergence of dangerous microcracks is given during the subsequent hot forming or press hardening. In particular, these are those areas in which the highest degrees of deformation are achieved during hot forming or press hardening. It has been found that where the highest degrees of deformation are achieved and the mechanical stresses leading to microcracks are highest, these mechanical stresses can be reduced by the presence of a lubricant, as already explained above. For this purpose, it may be sufficient that in a relevant area only on a tool effective surface, a lubricant is applied. It is also conceivable that with regard to different requirements in different areas different lubricants and / or different lubricant quantities are applied. The only local or regional application of a lubricant also has the advantage that the lubricant requirement is not higher than is absolutely necessary.

The lubricant application device belongs to the device according to the invention. The lubricant application device is preferably designed in such a way that the lubricant can be automatically or automatically applied to at least one freely accessible working effective area at least in regions (as explained above) when the tool is open. The lubricant application device can be structurally integrated into the tool. Likewise, the lubricant application device can be installed on the press side (for example, mounted on the press frame) or designed as a stand-alone device.

It is particularly preferred that the lubricant application device has at least one spray device attached to a robot or feeder, which can move in between the tool parts of the tool with this tool when the tool is open in order to apply the lubricant to at least one tool effective surface at least in regions.

The lubricant to be applied may be liquid during application. This liquid lubricant may contain volatiles that volatilize directly upon application and / or immediately after application, leaving a substantially viscous or solid lubricant film on the tooling surfaces. It is preferably provided that the lift-bearing lubricant with respect to the tool effective areas (even under the action of gravity) has good to very good adhesion properties, which may be adjusted only after the volatilization of corresponding components. Furthermore, it is preferably provided that the lubricant applied to the tool effective surfaces at least partially forms a closed and in particular also with respect to the layer thickness uniform lubricant film. Alternatively, it is conceivable that the applied lubricant in the form of individual drops or droplets adheres to the tool effective surfaces. Moreover, the lubricant to be applied may also be powdery. The adhesion of a powdered lubricant to the tooling surfaces can, for. B. be accomplished by electrostatic charging.

The lubricant application device preferably comprises at least one spraying device, such as, for example, a spray nozzle or the like, with which or through which a liquid or powdery lubricant can be dispensed. In particular, it is provided that the spray jet and / or spray that can be dispensed with the spray device is adjustable. Furthermore, it can be provided that the lubricant application device has a motor drive (for example, an automatically pivoting spray head), with which the direction of the spray jet and / or spray can be changed during application. The application or application of the lubricant can be supported by electrostatic charging, as in paint systems, both in liquid and in particular in powdered lubricants.

A lubricant application device could, for. As well as holes and or nozzles in the tool effective surfaces, in particular in the edge regions, comprise, through which the lubricant can be applied before or optionally also during the deformation of the sheet metal material.

It is preferably provided that the tool effective surfaces of the tool according to the invention are formed at least partially polished. In particular, those areas of the tooling surfaces are formed polished on which a lubricant is applied. A polished tool acting surface is understood to be a surface prepared by suitable machining whose mean roughness R _{z is} not more than 1.5 μm and in particular not more than 1.0 μm. In particular, it is a metallic surface. In conjunction with a lubricant applied, very favorable tribological conditions can be achieved during hot forming or press hardening of a sheet metal material coated with a metallic corrosion protection coating. Another advantage may be easy cleaning of polished tool surfaces. The tool according to the invention can have a plurality of polished regions, which can be designed identically or differently (for example with different roughness depths).

It is also preferably provided that the tool-acting surfaces of the tool according to the invention are textured at least in regions or are formed with texturing. In particular, those areas of the tool active surfaces are formed textured, on which a lubricant is applied. A textured tool interaction surface is understood to mean a structured surface which has been deliberately treated by suitable processes and which has microwells and, above all, closed microwells. In particular, it is a metallic surface. In conjunction with a lubricant applied, very favorable tribological conditions can be achieved during hot forming or press hardening of a sheet metal material coated with a metallic corrosion protection coating, since the applied lubricant can better adhere to the tool active surfaces or remain in the microwells. The tool according to the invention may have a plurality of textured areas which may be identical or different (i.e., having different textures).

It is also preferably provided that the tool-acting surfaces of the tool according to the invention are at least partially coated or have a coating (ie they are formed with a coating). In particular, those regions of the tool effective surfaces are coated on which a lubricant is applied. A coating is understood as meaning a layer that adheres firmly to the mold surfaces. Such a layer or coating is z. B. a hard material layer consisting of ceramic or metallic nitrides, carbides, oxides or borides. The accessible surface of this coating may be smooth and in particular polished or textured, as previously explained. In conjunction with a lubricant applied, very favorable tribological conditions can be achieved during hot forming or press hardening of a sheet metal material coated with a metallic corrosion protection coating. Another advantage may be easy cleaning of coated tool surfaces. Furthermore, longer service life may result. The tool according to the invention can have a plurality of coated regions which can be configured identically or differently (for example with different coating materials and / or surface properties). Alternatively or additionally, by the way, ceramic tool inserts can also be provided, which cover the individual area of the tool acting surfaces.

The tooling surfaces of the tool according to the invention may have polished, textured and / or coated areas. An optimal coordination of the condition of the Tool working surfaces (including any coating), the lubricant and the amount of lubricant can be determined for each individual case in experiments.

• – Bereitstellen eines Werkzeugs mit wenigstens zwei Werkzeugteilen, die zum Öffnen und Schließen dieses Werkzeugs relativ zueinander verfahrbar sind und die jeweils wenigstens eine direkt mit dem beschichteten Blechmaterial in Berührung kommende Werkzeugwirkfläche aufweisen, wobei es sich insbesondere um ein erfindungsgemäßes Werkzeug handelt;
• – Öffnen des Werkzeugs und zumindest bereichsweises Auftragen eines Schmiermittels auf wenigstens eine Werkzeugwirkfläche;
• – Erwärmen eines aus dem beschichteten Blechmaterial bestehenden Werkstücks und nachfolgendes Einlegen (des erwärmten Werkstücks) in das geöffnete Werkzeug, was insbesondere automatisiert erfolgt;
• – Schließen des Werkzeugs und Warmumformen bzw. Presshärten des Werkstücks, wobei sich (zumindest lokal) ein Schmiermittelfilm zwischen dem beschichteten Blechmaterial und der betreffenden Werkzeugwirkfläche ausbildet.

The method according to the invention for hot forming and in particular for press hardening a sheet metal material coated with a metallic corrosion protection coating comprises at least the following steps:

• - Providing a tool with at least two tool parts, which are movable relative to each other for opening and closing of this tool and each having at least one directly with the coated sheet material coming into contact tool effective surface, which is in particular a tool according to the invention;
• - Opening the tool and at least partially applying a lubricant to at least one tool effective area;
• - Heating a consisting of the coated sheet material workpiece and subsequent insertion (of the heated workpiece) in the open tool, which is particularly automated;
• - Closing of the tool and hot working or press hardening of the workpiece, wherein (at least locally) forms a lubricant film between the coated sheet material and the respective tool effective area.

The tool provided, which is in particular a hot forming tool or press hardening tool with an upper tool part (upper tool part) and a lower tool part (lower tool part), is typically installed in a forming press. With this forming press, the process movements for opening and closing the tool can be generated and forming and / or pressing forces are applied.

The sheet metal material to be hot-formed or press-hardened is inserted in the shape of a workpiece, as explained in more detail below, into the tool provided and then hot-formed or press-hardened after the tool has been closed. Thereafter, the tool is opened and the sheet material can be removed in the form of a sheet metal part from the tool.

The sheet metal material is predominantly a hot-workable and / or hardenable sheet steel material with a sheet thickness of 0.5 mm to 3.0 mm, preferably of 0.7 mm to 2.4 mm and in particular of 1.0 mm to 1, 6 mm. In particular, it is a hardenable steel material (for example a 22MnB5 material), which has a yield strength of 150 MPa to 1100 MPa and / or a tensile strength of 300 MPa to 1200 MPa in the initial state (as-delivered condition). According to the invention, it is provided that the sheet material or steel sheet material, when inserted into the tool, has a metallic corrosion protection coating at least in sections or in sections, and in particular on both sides and over the entire surface. This metallic corrosion protection coating is z. For example, a zinc-based or aluminum-based corrosion protection coating; d. H. The metallic anti-corrosion coating consists of zinc or aluminum or alloys based on zinc or aluminum. The metallic anticorrosive coating may also comprise multiple monolayers. The thickness of the metallic anticorrosive coating may be in the range of 5 μm to 20 μm, and preferably in the range of 9 μm to 11 μm. It is preferably provided that the metallic anti-corrosion coating has already been applied to the sheet material or steel sheet material by the manufacturer (that is, by the manufacturer of the sheet metal material). However, the metallic corrosion protection coating may also have been applied to the sheet material at another time, at the latest immediately before the insertion of the workpiece into the tool.

It is envisaged that the sheet material is heated to a corresponding temperature before forming, as explained above, which leads to austenitization or at least partial austenitization in a steel material as a function of the temperature. It is preferably provided that the workpiece (consisting of the coated sheet metal material) prior to insertion into the tool to a temperature of at least 650 ° C, preferably of at least 870 ° C, in particular of at least 900 ° C and particularly preferably of at least 930 ° C. is heated. The heating can, for. B. conductively (direct resistance heating), inductively and / or in an oven, such as. A continuous furnace done. In addition, it is preferably provided that a workpiece made of a steel sheet material when inserted into the tool at least partially has a temperature corresponding to the Austenitisierungstemperatur AC ₃ or a higher temperature.

The lubricant to be applied to the tooling surfaces is preferably a heat-resistant lubricant. In particular, it is an oil and graphite-free emulsion, with which oil and / or graphite-related deposits and residues do not occur both on the tool surfaces and on the produced sheet metal parts. When using an oil and graphite-free emulsion thus the cleaning effort is relatively low. The lubricating effect of an oil and graphite-free emulsion can, for. B. be improved by containing temperature-resistant salt crystals, which act as the smallest rolling body and thus create favorable tribological conditions during hot forming or press hardening.

The application of a lubricant to the mold surfaces, the accessibility provided, manually, for example, done with a sponge or with a hand spray gun. Preferably, however, it is provided that the application of a lubricant to the tool acting surfaces automatically, for example. With a lubricant application device takes place, as already explained. In particular, in the context of a supplementary measure, the lubricant can also be applied directly to the heated sheet material. The application of a lubricant directly to the sheet material or its metallic corrosion protection coating may, for. B. before inserting the workpiece into the tool and / or after inserting the workpiece in the tool (and before closing the tool) done. The application of the lubricant to the sheet material can be done manually or automatically. Otherwise, the preceding and following explanations apply analogously.

A first particularly preferred variant of the method provides that the workpiece consisting of the coated sheet material (when inserted into the tool) is a substantially planar board. A board is understood to mean a sheet metal blank produced from a metal sheet or a sheet metal strip. During hot forming, a sheet metal part is produced directly from the previously heated board. The tool (hot forming tool) has a shaping function here. Furthermore, the tool can also have a heating function. The same applies to press hardening, wherein an at least partially hardened sheet metal part is produced from the previously heated blank in a single operation. The tool (press hardening tool) has a shaping and cooling function. Such a variant of the method may be referred to as direct hot forming or press hardening.

A second particularly preferred variant of the method provides that the workpiece consisting of the coated sheet material (when inserted into the tool) is a cold-formed sheet metal shaped part or intermediate shaped part. When hot forming a sheet metal part (with a different geometry) is produced from this previously heated intermediate molding. The tool (hot forming tool) here has a shaping or shape-changing function. Furthermore, the tool can also have a heating function. In press hardening, the previously heated intermediate molding is cooled by applying a pressing force. The tool (press hardening tool) has a cooling function here. Furthermore, depending on the shape of the intermediate molding, the tool also has a reshaping or finished-forming, a shape-retaining or a shape-calibrating function. Such a variant of the method may be referred to as indirect hot forming or press hardening.

The tool according to the invention and / or the method according to the invention make it possible to produce a shaped sheet metal part from a sheet metal material coated with a metallic corrosion protection coating. In spite of a preferably complex geometry or design, a shaped sheet metal part produced in this way has (at least regionally) a metallic anticorrosive coating which, in particular, exhibits no or only very small microcracks with a depth of not more than 10 μm.

A sheet-metal shaped part produced using the tool and / or method according to the invention can be a component which is essentially ready to be installed, wherein full surface or local cleaning of the component surfaces can follow. Such a component is in particular a vehicle part such as, for example, a body or chassis part for a motor vehicle. A sheet-metal shaped part produced using the tool and / or method according to the invention can also be a sheet-metal shaped part to be further processed (which also includes shaping machining steps). Optionally, any resulting from the hot forming or press hardening and in particular caused by the lubricant residues remain without affecting further processing steps on the component.

Advantageously, the invention enables the production of high quality "galvanized" sheet metal parts with higher-strength properties of a starting steel sheet material, which already has a zinc coating (zinc-based metallic corrosion protection coating). According to the invention, this production succeeds advantageously by direct hot forming or press hardening of the coated starting sheet material.

The invention will now be described by way of example and not by way of limitation with reference to the schematic figures. The features shown in the figures and / or explained below are independent of shown and / or described combinations of features at the same time general features or training features of the invention.

1 shows an overview of a process according to the invention enclosing sequence for producing a sheet metal part.

2 shows a sectional view of an inventive device for hot working or press hardening.

3 shows in a sectional view another device according to the invention for hot forming or press hardening.

In the 1 shown sequence for producing a sheet metal part comprises several designated I to VI steps, which are explained in more detail below. However, not all illustrated and / or illustrated steps necessarily fall within the claimed scope. Furthermore, the method according to the invention can comprise further steps or substeps, which are described in the sequence of FIGS 1 not shown and / or which are not explained below. Furthermore, individual steps can be performed at the same time or overlapping in time.

The sequence shown begins in step I with the provision of a starting sheet material. The starting sheet material is a sheet steel material suitable for hot working and / or press hardening, which is coated with a metallic anti-corrosion coating, in particular zinc-based. Preferably, this metallic anti-corrosion coating is applied over the entire area on both sides of the steel sheet material provided.

The trained with a metallic anti-corrosion coating steel sheet material is z. B. provided as a coil belt or as a stack of boards. In step II, a board blank is produced from the flat starting sheet material. Alternatively, the starting steel sheet material may be provided directly as a cut sheet metal blank.

The sheet metal plate produced in step II is heated in step IV to a temperature of several hundred degrees Celsius. The heating can be complete or partial. The heating can, for. B. in a furnace and in particular continuous furnace and / or be made by an inductive heating device.

Subsequently, the heated and still flat sheet metal blank is placed in a hot forming tool and hot-formed. This hot forming takes place in step VI. The sheet metal molding obtained by the hot forming is designated by P.

It is preferably provided that the hot forming in step VI is combined with a press hardening. For this purpose, the sheet metal plate produced in step II is first heated to a temperature above 870 ° C and cooled during hot forming still in the hot forming tool or press hardening tool, which in a known manner increases the strength of the steel sheet material enters, as explained above.

The sequence explained above corresponds to direct hot forming or direct press hardening, in which case a flat sheet metal blank is heated and transformed directly into a shaped sheet metal part P. Alternatively, there is the possibility of indirect hot forming or indirect press hardening, wherein the plane sheet metal plate produced or otherwise provided in step II is first preformed in step III to an intermediate molding and then hot worked this intermediate molding after heating (step IV) is press-hardened (step VI).

According to the invention, a step V is provided, in which a lubricant is applied at least in regions before inserting the heated steel sheet material (in the form of a flat sheet metal blank or in the form of an intermediate molding) into the opened hot forming tool or press hardening tool. Alternatively or additionally, the lubricant can also be applied at least in regions directly to the heated steel sheet material (step Va). It is also conceivable to apply the lubricant directly to the steel sheet material before heating (step IV) or in a heating pause.

The lubricant applied to the tooling surfaces and / or to the steel sheet material prevents or reduces the occurrence of microcracks in the metallic anticorrosive coating and / or at the boundary between the metallic anticorrosive coating and the steel sheet material, as discussed above. Furthermore, a very good surface quality of the metallic corrosion protection coating can be achieved. In addition, a good heat transfer in the press hardening tool can be achieved, in particular during press hardening.

In the 1 illustrated steps I to VI can be accomplished in a system for manufacturing and in particular for the automated production of hot-formed or press-hardened sheet-metal shaped parts by means of corresponding devices and / or devices. The application of a lubricant in step V and the hot working or press hardening in step VI may e.g. B. with the in 2 shown and explained in more detail below device are performed.

In the 2 The device or system shown comprises, by way of example, a press-hardening tool 100 (A hot forming tool is constructed essentially identical), which in a not illustrated forming press is installed. To the tool 100 heard a first, lower tool part 110 and a second, upper tool part 120 ,

The lower tool part 110 has a shaping tool acting surface 111 on. Also the upper tool part 120 has a shaping and tool effective area 111 corresponding tool effective area 121 on. With 112 and 122 are areas of the tool surfaces 111 and 121 or inserts in the tool surfaces 111 and 121 designated, which are provided with a coating and in particular with a hard coating, to which reference is made to the relevant above explanations.

Between the tool surfaces 111 and 121 For example, a heated sheet steel material may be reshaped (or molded) and simultaneously cooled as previously explained. To accomplish the cooling, are both in the lower part of the tool in a known manner 110 as well as in the upper tool part 120 cooling channels 115 and 125 available.

The apparatus further comprises one or more lubricant applicators for automatically applying a lubricant to the tooling surfaces 111 and 121 of the tool 100 , Applying the lubricant to the tool surfaces 111 and 121 takes place when the tool is open 100 and before inserting the existing of the steel sheet material workpiece. For this bring in the spray heads 131 and 132 arranged spraying in the form of spray nozzles each have a directed spray or a spray 140 of the lubricant to be applied. The applied lubricant is impacted on the tool surfaces 111 and 121 at the lower part of the tool 110 and on the upper part of the tool 120 down and forms a lubricant film. Around all areas or at least the relevant areas of the tool areas 111 and 121 with the spray or spray 140 To be able to capture, the spray nozzles are in pivoting spray heads 131 and 132 arranged, which is illustrated by the illustrated pivot arrows.

In the in 2 The apparatus shown are associated with a lubricant application device or to different lubricant application devices spray heads 131 and 132 by way of example at the lower part of the tool 110 and on the upper part of the tool 120 attached. Alternatively, the spray heads 131 and 132 be attached to the press body of the forming press. Furthermore, a stand-alone solution is possible, ie the spray heads 131 and 132 belong to at least one separate device which, for example, is positioned next to the forming press.

The 3 shows an apparatus in which a lubricant application device is provided, one on a robot or feeder 135 guided spray head 133 having exemplified two spray nozzles. The spray head 133 can be press-tied with the tool open 100 between the tool parts 110 and 120 retract and at the same time a spray or spray 140 on both tool surfaces 111 and 121 apply, which is preferably fully automatic. Advantageously, the lubricant application can be very targeted here. Furthermore, the lubricant is applied with respect to the tool effective surfaces 111 and 121 not from a lateral direction but substantially from the normal direction (ie, substantially perpendicular to the tooling surfaces 111 and 121 ). The spray head 133 can also be designed as a pivotable spray head. Otherwise, the preceding explanations apply analogously.

It can be provided that the application of a lubricant is carried out by at least one spraying device in an electrostatic field. For this purpose, the spraying device is placed with respect to the tool effective surfaces to an electrically positive potential or to an electrically negative potential. Similar procedures are known from the painting technique.

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• DE 20122563 U1 [0005, 0012]
• DE 102010024664 A1 [0005, 0012]

Claims (10)

Apparatus for hot forming and in particular for press hardening a sheet metal material coated with a metallic anti-corrosion coating, comprising a tool ( 100 ) with at least two tool parts ( 110 . 120 ), which are movable relative to one another for opening and closing the tool, and which each have at least one tool acting surface directly in contact with the coated sheet material ( 111 . 121 ), characterized in that this device further comprises at least one lubricant application device ( 131 . 132 . 133 ) with the tool ( 100 ) on at least one tool effective area ( 111 . 112 ) at least partially a lubricant ( 140 ) can be applied, which in the subsequent hot forming or press hardening a lubricant film between the coated sheet material and the relevant tool effective area ( 111 . 112 ) trains. Apparatus according to claim 1, characterized in that the lubricant application device ( 131 . 132 . 133 ) comprises at least one spraying device through which a liquid or powdered lubricant ( 140 ) is ausbringbar. Device according to claim 2, characterized in that the spraying device ( 133 ) on a robot or feeder ( 135 ) and by means of this robot or feeder ( 135 ) with the tool open ( 100 ) between the tool parts ( 110 . 120 ) can retract to at least one tool effective area ( 111 . 112 ) at least partially the lubricant ( 140 ) apply. Apparatus according to claim 1, 2 or 3, characterized in that the tool effective area ( 111 . 112 ) of the tool ( 100 ) is at least partially polished and / or textured, or that the tool effective area ( 111 . 112 ) at least partially a coating ( 111 . 112 ) having. A method of hot working, and in particular press hardening, a sheet metal material coated with a metallic anticorrosive coating, comprising the steps of: - providing a tool ( 100 ) with at least two tool parts ( 110 . 120 ) used to open and close this tool ( 100 ) are movable relative to each other and the at least one directly with the coated sheet material coming into contact tool effective area ( 111 . 112 ), in particular a tool ( 100 ) according to any one of the preceding claims; - opening the tool ( 100 ) and at least partially applying a lubricant ( 140 ) on at least one tool effective area ( 111 . 112 ); Heating a workpiece consisting of the coated sheet material and subsequently placing it in the opened tool ( 100 ); - Close the tool ( 100 ) and hot working of the workpiece, wherein a lubricant film between the coated sheet material and the respective tool effective area ( 111 . 112 ) trains. A method according to claim 5, characterized in that the workpiece before insertion into the tool ( 100 ) is heated to a temperature of at least 650 ° C and preferably at least 870 ° C. A method according to claim 5 or 6, characterized in that it is the coated sheet material is a steel sheet material, which is coated on both sides with a metallic anti-corrosion coating zinc-based or aluminum-based. Method according to one of the preceding claims 5 to 7, characterized in that on the tool effective area ( 111 . 112 ) to be applied lubricant ( 140 ) is a heat-resistant lubricant, which is preferably an oil and graphite-free emulsion and in particular a salt crystal-containing emulsion. Method according to one of the preceding claims 5 to 8, characterized in that the consisting of the coated sheet material workpiece is a substantially planar board. Method according to one of the preceding claims 5 to 8, characterized in that the workpiece consisting of the coated sheet material is a cold preformed sheet metal part.

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