KR20170087903A - Method for hot or warm forming a workpiece and production plant for hot or warm forming a workpiece - Google Patents

Abstract

The present invention relates to a method for hot or warm forming a workpiece comprising the steps of providing a workpiece to be shaped, a method of at least partially pretreating the workpiece, A method of at least partially heating and at least partially molding and / or curing a workpiece, wherein the time between the pre-processing method step of the workpiece and the heating method step causes the workpiece to be at least partially Washed.

Description

TECHNICAL FIELD [0001] The present invention relates to a hot or warm forming method of a workpiece, and a manufacturing facility for hot or warm molding of a workpiece. BACKGROUND OF THE INVENTION 1. Field of the Invention [0002]

The present invention relates to a method for hot or warm forming a workpiece and a manufacturing facility for hot or warm forming the workpiece.

In hot and warm forming, generally uncoated or coated materials are used. In order to prevent corrosion during transportation, semi-finished products in coil form or sheet form are provided partially, preferably completely, with anti-corrosion oil or lubricant. In addition, contamination by dust or the like in the coil or sheet storage warehouse is not usually prevented at all.

Thermal degradation of the materials deposited on the semi-finished product occurs as caused by the thermal process that occurs when the desired temperature is reached for the tempering process. As a result of this thermal decomposition, contaminants remain on the semi-finished product, and these contaminants degrade the quality of the semi-finished product once again. In this case, mechanical washing, for example, by shot blasting, can no longer completely remove the resulting residues, or may damage the coated semi-finished products in particular. In addition, high oil residues can enhance hydrogen absorption in the material during processing of the semi-finished product, for example, through a high oil film. This can cause material brittleness due to high strength. In the case of micro-oiling, this behavior is not confirmed, but sufficient corrosion protection can not be guaranteed in this case.

It is an object of the present invention to provide a method for hot or warm forming a workpiece, which further improves the quality of parts manufactured through hot or warm forming compared to the prior art.

The above object is achieved according to the present invention by a method for hot or warm forming a workpiece,

A method comprising: providing a workpiece;

A process step of at least partially pretreating the workpiece,

A method of at least partially heating a workpiece to a target temperature in a heating station,

A method of hot or warm forming a workpiece, comprising the steps of at least partially forming and / or curing the workpiece,

Wherein the workpiece is at least partially cleaned during the cleaning step between the pre-processing method step and the heating method step of the workpiece over time.

Compared to the prior art, the workpiece is cleaned for the molding and / or curing process steps after the temporal pretreatment process step and before the temporal heating process step, while at the same time the residues deposited on the workpiece, Removed. As a result, the quality of the parts produced after the molding step of the workpiece in time is improved, because the probability of deposition of contaminants formed in residues during heating of the workpiece and consequently the probability of permanent damage to the workpiece is reduced Because. In addition, during the cleaning step, other contaminants, such as dust, may also be removed from the workpiece.

In this case, preferably, the cleaning step is performed just before the heating method step. Also, preferably, the workpiece is a part of a vehicle or a chassis component that is manufactured after the molding and / or curing process steps. Particularly, the work piece is provided as a sheet metal part, in particular as a flat steel plate blank (direct hot forming) or as a molded part (indirect hot forming) having almost its own final geometry, and the pretreatment is at least part of the manufacturing process of the sheet metal part . Also preferably, the partial area of the workpiece, preferably the entire workpiece, which is to be heated to the target temperature during the desired heating, is cleaned in the cleaning step. However, it is also conceivable that partial areas of the desired workpiece may be cleaned as desired with improved surface quality on the parts that are generally manufactured.

Preferred embodiments and improvements of the present invention can be ascertained from the description in connection with the dependent claims and the drawings.

According to a further embodiment of the invention, the workpiece is treated at least partially chemically, mechanically and / or thermally in the cleaning step. In this case, the selected cleaning method is preferably matched to the workpiece in a manner that does not substantially degrade the properties of the workpiece due to cleaning. As a result, in a preferred manner, it is ensured by the cleaning step that no measures are taken to compromise the quality of the subsequently produced parts.

According to a further embodiment of the invention, the workpiece is at least partially cleaned in the cleaning bath in the cleaning step. During the chemical treatment of such a workpiece, the pollutants are bound in the liquid of the wash bath in a desirable manner. In this case, it can be conceived that the liquid in the cleaning bath is exchanged by the liquid flowing into the cleaning bath and flowing out again, for example, pumped into the cleaning bath in the liquid circuit and pumped out from the cleaning bath again. Through the combination of contaminants in the liquid, in a preferred manner, contaminants are prevented from spreading through the air and depositing on, for example, equipment components. It is also conceivable that the wet workpiece is dried before the time step of the heating process, for example, with hot air.

According to a further embodiment of the present invention, the workpiece is subjected to a brushing treatment in the cleaning step. For such a mechanical treatment in the cleaning step, it is conceivable that the workpiece is brought into contact with the brush so that the workpiece is moved in the longitudinal direction and the brush extends substantially along the lateral direction of the workpiece. Thus, the cleaning step is integrated into the transfer of the workpiece toward the heating station in a preferred manner, with no substantial delay during the hot or warm forming process through the cleaning step. It is also conceivable that a system of brushes or brushes is disposed at the inlet to the heating station, thereby providing cleaning of the workpiece immediately prior to the heating method step. As an alternative, it is conceivable to manually clean the workpiece. During manual cleaning with a brush, clearly noticeable residues can be removed in a desirable manner without further effort.

According to a further embodiment of the present invention, the workpiece is heated to the cleaning temperature by the burner in a cleaning step. Preferably, the workpiece is uniformly heated by one or more burners, preferably on both sides, in particular throughout. In this case, it is conceivable that during the heating, the burner moves along the transverse or longitudinal direction of the workpiece, preferably with oscillation. Through the heating already performed during the cleaning of the workpiece, only a relatively small heating energy is required at the heating station to achieve the target temperature. In this case, preferably, in order to prevent the contaminants in the exhaust gas, which are generated when heating to the cleaning temperature, from depositing on the equipment parts when heated to the target temperature, Station. In addition, the cleaning step may be performed in the heating station by heating the workpiece to the cleaning temperature first and then to the target temperature, under the condition that the target temperature is higher than the cleaning temperature You can think. In this case, preferably, when the workpiece is heated to the cleaning temperature, the surrounding air of the workpiece is sucked and discharged by, for example, an exhaust hood to discharge the contaminants.

According to a further embodiment of the invention, the workpiece is transferred or moved during the cleaning step. Thus, the cleaning step is incorporated in the hot or warm forming process of the workpiece in such a way that the potential delay through the cleaning step is kept as short as possible. If the cleaning step corresponds to a heat treatment, it may be conceivable that the workpiece is moved by the burner belt along the conveying direction and the burner heats the workpiece during the sliding movement. In particular, the workpiece is moved along the transport direction by a transport mechanism and, at the same time, passes through a cleaning station, a heating station, and reaches a forming and / or hardening die.

According to a further embodiment of the present invention, the workpiece is transported from the cleaning station to the heating station between the time cleaning step and the heating method step. In the case of thermal cleaning, preferably, the transfer path is connected in as short a time as possible to prevent the workpiece from cooling again. In particular, it may be contemplated that the transfer mechanism includes heating elements that allow the workpiece to substantially maintain its cleaning temperature. In this case, preferably, the workpiece is transported in a manner such that the workpiece is not soiled or contaminated again. In particular, the workpiece is moved along the transport direction by the transport mechanism and at the same time through the cleaning station, the heating station, and arrives at the forming and / or curing die.

According to a further embodiment of the present invention, the workpiece is heated to the target temperature by an additional burner during heating for the molding and / or curing process step. Preferably, the temperature as the target temperature is selected between 600 [deg.] C and 900 [deg.] C. If a manganese-boron steel is used, preferably a target temperature above AC3 is achieved, preferably to completely convert the microstructure to austenite. When the target temperature is lower than AC3 and exceeds AC1, a mixed microstructure composed of austenite and ferrite is secured. For example, the rate at which the workpiece is heated to the cleaning temperature during use of the burner is higher than the rate at which the workpiece is heated to the target temperature, particularly when using a radiant furnace.

According to a further embodiment of the present invention, in order to prevent corrosion during transport, the workpiece is coated with a protective material and / or at least partially with an anti-corrosion oil.

According to a further embodiment of the invention, the burner and / or the additional burner are operated with a fuel gas and an oxygen-containing gas. Preferably, the heating capacity of the burner and / or the additional burner is adjusted through the mixing ratio of the fuel gas and the oxygen-containing gas. Particularly through the oxygen content, the maximum temperature in the combustion flame of the burner and / or the additional burner is determined. In this case, for example, the additional burner is supplied with a technical oxygen mixture, the oxygen content is preferably greater than 70%, particularly preferably greater than 90%. Further, in order to achieve the target temperature at a desired speed for heating the workpiece, the spacing distance between the burner and the workpiece, the oxygen content, and / or the conveyance speed of the workpiece conveyed along the conveyance direction are adjusted accordingly.

According to a further embodiment of the present invention, the workpiece is placed in a forming / curing die for molding and / or curing process steps. Preferably, the molding / curing die is at least partially cooled and, as a result, partially cures the workpiece in a desired manner.

According to a further embodiment of the present invention, a steel sheet blank is used as a workpiece. For example, the workpiece is a workpiece made substantially of manganese-boron steel, particularly 22MnB5, or a steel sheet blank containing a relatively higher carbon content.

A further object of the present invention is a manufacturing facility for the hot or warm forming of a workpiece, in particular for carrying out the method according to the invention, comprising a cleaning station for cleaning the workpiece and a cleaning station for cleaning the cleaned workpiece And a heating station for heating.

Compared to the prior art, the manufacturing facility according to the invention is characterized in that the cleaning station removes possible residues by a pre-treatment of the workpiece and reduces the amount of potential contaminants which may degrade the quality of the subsequently produced parts, And the like.

According to a further embodiment of the invention, the manufacturing facility comprises a transport mechanism. With the transfer mechanism, the workpiece is transferred to the forming / curing die via the cleaning station and the heating station in a preferred manner. In this case, it is conceivable that the transport mechanism includes transport rollers.

According to a further embodiment of the invention, the cleaning station is structurally separate from the heating station. Thus, in a preferred manner, contaminants separated through heating the workpiece to the cleaning temperature can be assured of spreading through the air and then depositing on the installation components of the heating station.

Further details, features and advantages of the invention are set forth in the following description of the preferred embodiments and in the drawings. At the same time, the drawings only illustrate exemplary embodiments of the present invention, and these embodiments do not limit the scope of the present invention.

Figs. 1A to 1D are views each showing a method for hot or warm forming a workpiece according to an exemplary embodiment of the present invention. Fig.

In the various figures, the same parts are always given the same reference numerals, and for that reason the parts are generally named and referred to only once each.

1A to 1D show a method for hot or warm forming a workpiece 1 according to an exemplary embodiment of the present invention. Here, for example, it relates to a structure for an automobile or a chassis part, and the work piece 1 is provided as a semi-finished product, in particular in the form of a tailored rolled blank, or as a steel plate blank as shown in Fig. In this case, the workpiece 1 is made of, for example, a material at least partially made of boron-manganese steel, especially 22MnB5. Through a hot or warm forming process, the workpiece (1) is preferably delivered in its final or ultimate form as a part. In order not to affect the properties and / or shape of the parts to be manufactured at a later time, the work piece 1 is treated with a pretreatment. An example of the pretreatment is a step of coating the workpiece 1 with a corrosion inhibiting oil or a lubricant to prevent corrosion during transportation of the workpiece. Another example of the pretreatment is a step of applying cutting oil on the work 1 so as to facilitate cutting of the steel sheet that may be present before hot or warm-forming. Through pretreatment, and through other external circumstances, residues of, for example, anticorrosion oil, lubricant and / or cutting oil remain on the workpiece 1 intact. During heating of the workpiece 1 required for a hot or warm forming process, the residues may cause damage or deterioration, for example in the form of material embrittlement, on the parts made of the contaminants. To prevent said degradation, the pretreated workpiece 1 is preferably cleaned in the cleaning stage just before heating the workpiece 1 in the heating station 20. Preferably, the cleaning step is started 60 seconds before, preferably 20 seconds before, particularly preferably 5 seconds before heating the workpiece (1).

As an example of the cleaning step, in the embodiment in Figs. 1A-1D, the heat treatment in the cleaning station 10 is shown in Fig. 1B. In the present embodiment, the cleaning station 10 includes a burner belt or a roller conveyor 4 disposed under the work 1 to be conveyed by the roller conveyor 4. Also, preferably, the cleaning station 10 comprises a burner 2 disposed above and / or below the transportable workpiece 1. Further, in this case, the burner 2 heats the workpiece 1 to the cleaning temperature. To this end, the burner 2 is in particular operated with a mixture consisting of a burner gas and an oxygen-containing gas. Further, a burner flame 3 is generated when the burner 2 is used to heat the workpiece 1 at the cleaning temperature, and this burner flame is directly contacted to the work 1 in the cleaning station 10, Or is spaced apart from the workpiece by an interval. Particularly, the burner belt or the roller conveyor 4 includes the recess 6 in one position so that the burner flame 3 can heat the work 1 without interruption. In addition, the work 1 is heated on both sides through one burner 2, in order to remove the residues as much as possible from the surface of the work 1 as much as possible. In this case, in order to realize heating along the transversely extending portion of the work 1 together with the corresponding movement, the burner 2 is moved along the direction perpendicular to the conveying direction of the burner belt or the roller conveyor 4 It is conceivable to move while vibrating, preferably. Particularly, the cleaning temperature is determined by determining the conveying speed of the work 1 to be conveyed by the burner belt or the roller conveyor 4, determining the spacing distance of the burner 2 from the work 1, and / It is conceivable that it is adjusted or realized through the determination of the oxygen content of the oxygen-containing gas to be mixed. Also preferably, the burner flame 3 of the burner 2 in the cleaning station 10 heats the workpiece 1 homogeneously, i. E. Uniformly along the surface. The cleaning station 10 also includes an exhaust gas system for discharging contaminant gases generated during the heat treatment to the exhaust gas system. Accordingly, the pollutants contained in the polluted gas are prevented from being deposited on the equipment parts of the cleaning station 10. [ Subsequently, in order to prevent contaminants contained in the contaminant gas from depositing on equipment components, for example disposed in the heating station 20, the cleaning station 10 in the illustrated embodiment is structurally As shown in FIG.

1C, a heating station 20 is shown in the form of a furnace 5, in which the workpiece 1 is placed inside the furnace 5, preferably inside a closed furnace, for heating. In particular, the target temperature is higher than the cleaning temperature. In addition, the workpiece 1 is heated by additional burners or by radiation within the heating station 20, and the additional burner is preferably operated by a mixture of a fuel gas and an oxygen-containing gas. In particular the additional burner in the heating station 20 is operated with technical oxygen whose oxygen content is preferably more than 75%, particularly preferably more than 90%. For example, heating in the heating station 20 can be used for adjustment of the material properties of the parts to be manufactured subsequently. For example, the workpiece 1 is heated to a temperature below AC3, in particular below AC1, and / or at least in a second region, in order to prevent complete austenitization as desired in at least the first region, And is heated to a temperature above AC3 to cause kneading. It is also conceivable that the workpiece (1) is precoated after the time of the washing step and before the time of the heating method step, in order to provide alloy layer formation on the surface of the workpiece (1) with a corresponding pre-coating. The cleaning station 10 is also connected to the heating station 20 via a transfer mechanism 4. In particular, the cleaned workpiece 1 is transferred into the furnace 5 by the transfer mechanism 4.

After heating the cleaned workpiece 1, the workpiece 1 is inserted into a cooled molding and / or curing die 30, as shown in FIG. 1d, where it is molded and / or cured . In particular, the forming and / or curing die 30 includes a mold that matches the part to be manufactured. It is also conceivable that the transfer mechanism transfers the workpiece 1 along the transfer direction in the manufacturing facility via the cleaning station 10 and the heating station 20 into the molding and / or hardening die 30

1: Workpiece
2: Burner
3: Burner flame
4: Feed mechanism, burner belt, roller conveyor
5: No
6: recess
10: Cleaning station
20: Heating station
30: Molding and / or curing die

Claims (15)

A method for hot or warm forming a work (1)
A method comprising: providing a workpiece (1)
A method step of at least partially pretreating the work piece (1)
A method of at least partially heating a workpiece (1) to a target temperature within a heating station (20)
A method of hot or warm forming a workpiece, comprising the steps of at least partially forming and / or curing the workpiece (1)
Characterized in that the workpiece (1) is at least partially cleaned in the cleaning step between the pre-processing method step and the heating method step of the workpiece (1) in time. The method according to claim 1, wherein the workpiece (1) is treated at least partially chemically, mechanically and / or thermally in a cleaning step. 3. A method according to claim 1 or 2, wherein the workpiece (1) is at least partially cleaned in the cleaning bath in the cleaning step. 4. A method according to any one of claims 1 to 3, wherein the workpiece (1) is subjected to a brushing treatment in a cleaning step. The method according to any one of claims 1 to 4, wherein the workpiece (1) is heated by the burner (2) to a cleaning temperature in a cleaning step. 6. A method according to any one of claims 1 to 5, wherein the workpiece (1) is conveyed during the cleaning step. 7. Process according to any one of the preceding claims, characterized in that the workpiece (1) is conveyed from the cleaning station (10) to the heating station (20) between the time washing step and the heating method step, Molding method. 8. A method according to any one of claims 1 to 7, wherein the workpiece (1) is heated to a target temperature by an additional burner. 9. A method according to any one of claims 1 to 8, wherein the workpiece (1) is coated with a protective material and / or with a corrosion-inhibiting oil. 10. A method according to any one of claims 5 to 9, wherein the burner (2) and / or the additional burner is operated with a fuel gas and an oxygen-containing gas. Process according to one of the claims 1 to 10, characterized in that the workpiece (1) is placed in a forming and / or curing die (30) for forming and / or curing process steps, . The method for hot or warm forming a workpiece according to any one of claims 1 to 11, wherein a steel sheet blank is used as the workpiece (1). A manufacturing facility for performing hot or warm forming of a workpiece (1), in particular a manufacturing facility for carrying out the method according to any one of the claims 1 to 12, characterized in that the manufacturing facility comprises a cleaning A manufacturing facility for hot or warm forming of a workpiece, comprising a station (10) and a heating station (20) for heating the cleaned workpiece. 14. The manufacturing facility according to claim 13, wherein the manufacturing facility comprises a transfer mechanism (4). 15. A manufacturing facility for hot or warm forming of a workpiece according to claim 13 or 14, wherein the cleaning station (10) is structurally separate from the heating station (20).

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