Method for producing a motor vehicle component from a 6000-series aluminum alloy

Abstract

The present disclosure relates to a method for producing a motor vehicle component from a 6000-series aluminum alloy having the following method steps: providing a blank made of a 6000-series aluminum alloy, rapid heating of the blank by means of contact plates to a temperature between 450° C. and 600° C. in a time less than 20 seconds, ending of the heating procedure and optional homogenizing when a grain size between 20 and 50 μm has resulted, quenching the blank thus tempered to a temperature less than or equal to 100° C., in a time less than 20 seconds, wherein the rapid heating and quenching of the blank is carried out in a total time of less than 50 seconds, applying a lubricant, at 20° C. to 100° C., forming the cooled blank in a forming tool, wherein the time between beginning the rapid heating and beginning the forming is less than 45 seconds, aging.

Claims

1. A method of producing a motor vehicle component from a 6000-series aluminum alloy, the method comprising: rapid heating of a blank comprising 6000-series aluminum alloy, using contact plates, to a temperature between 450° C. and 600° C. in a time of less than 20 seconds, ending the rapid heating in response to obtaining a grain size between 20 and 50 μm, quenching the blank to a temperature of less than or equal to 100° C., in a time of less than 20 seconds to form a tempered blank, the rapid heating and the quenching of the blank is performed in a total time of less than 50 seconds, applying a lubricant at 20° C. to 100° C. to the tempered blank, forming the tempered blank in a forming tool, the time between beginning of the rapid heating and beginning of the forming is less than 50 seconds, and stabilizing or aging the tempered blank, wherein the 6000-series aluminum alloy comprises the following alloy elements, expressed in weight-percent: TABLE-US-00004 silicon (Si) 0.60 to 1.00 magnesium (Mg) 0.65 to 0.95 copper (Cu) 0.25 to 0.90 remainder aluminum and smelting-related contaminants.

2. The method according to claim 1, wherein the aluminum alloy comprises copper at 0.25-0.65.

3. The method according to claim 1, wherein the aluminum alloy comprises copper at 0.65-0.90 weight-percent.

4. The method according to claim 1, wherein the aluminum alloy further comprises at least one of the following alloy elements, expressed in weight-percent: TABLE-US-00005 manganese (Mn) 0.10 to 0.20 chromium (Cr) up to 0.10 titanium (Ti) 0.01 to 0.10 iron (Fe) 0.10 to 0.30.

5. The method according to claim 1, wherein a yield strength Rp0.2 of the 6000-series aluminum alloy tempered blank greater than 260 MPa is set from the stabilizing or the aging.

6. The method according to claim 1, wherein a yield strength Rp0.2 of the 6000-series aluminum alloy tempered blank greater than 320 MPa is set from the stabilizing or the aging.

7. The method according to claim 1, wherein a ratio of yield strength to tensile strength of the 6000-series aluminum alloy tempered blank less than or equal to 0.95 is set from the stabilizing or the aging.

8. The method according to claim 1, wherein the blank is in the roll-hardened state before the heating.

9. The method according to claim 1, wherein the heating or the quenching of the 6000-series aluminum alloy is performed locally.

10. The method according to claim 1, wherein the heating or the quenching of the blank is with different contact pressure, or using the contact plates having different temperatures in the heating or the quenching to obtain different regions of the blank based on the different temperatures.

11. The method according to claim 1, wherein the heating is performed by contact heating at a heating rate greater than 20 K/s.

12. The method according to claim 1, wherein the contact plates comprise a coating.

13. The method according to claim 1, further comprising cooling, wherein the heating, the cooling, and/or the forming is performed in multiple stages.

14. The method according to claim 1, wherein the aluminum alloy comprises the following alloy components, expressed in weight-percent: TABLE-US-00006 silicon (Si) 0.60 to 1.00, preferably 0.60 to 0.90 magnesium (Mg) 0.65 to 0.95 copper (Cu) 0.25 to 0.90 manganese (Mn) 0.10 to 0.20 chromium (Cr) up to 0.10 titanium (Ti) 0.01 to 0.10 iron (Fe) 0.10 to 0.30 remainder aluminum and smelting-related contaminants, wherein the heating of the blank is a heating rate of greater than 4 K/s, the quenching of the blank is at a cooling rate of greater than 10 K/s, and cold forming of the motor vehicle component is performed within less than 50 seconds after the heating.

15. The method according to claim 14, wherein the motor vehicle component comprises a yield strength Rp0.2 of greater than 260 MPa and a ratio of yield strength to tensile strength of less than or equal to 0.95 and is selected from the group consisting of: a motor vehicle column, a tunnel, longitudinal beam or crossbeam, a rocker panel, a door frame, reinforcements and stiffening elements, and a battery mount, frame, reinforcements and/or stiffening elements.

16. The method according to claim 1, wherein a yield strength Rp0.2 of the 6000-series aluminum alloy tempered blank greater than 280 MPa and less than 340 MPa is set.

17. The method according to claim 1, wherein a yield strength Rp0.2 of the 6000-series aluminum alloy tempered blank greater than 280 MPa and less than 320 MPa is set.

18. The method according to claim 1, wherein the heating of the blank is at a heating rate greater than 15 K/s.

19. The method according to claim 1, wherein the quenching of the blank is at a cooling rate greater than 15 K/s.

20. The method according to claim 1, wherein the aluminum alloy comprises the following alloy elements, expressed in weight-percent: TABLE-US-00007 silicon (Si) 0.60 to 0.90 magnesium (Mg) 0.65 to 0.95 copper (Cu) 0.25 to 0.90 remainder aluminum and smelting-related contaminants.

21. The method according to claim 1, wherein the aluminum alloy comprises the following alloy components, expressed in weight-percent: TABLE-US-00008 silicon (Si) 0.60 to 0.90 magnesium (Mg) 0.65 to 0.95 copper (Cu) 0.25 to 0.90 manganese (Mn) 0.10 to 0.20 chromium (Cr)   up to 0.10 titanium (Ti) 0.01 to 0.10 iron (Fe) 0.10 to 0.30 remainder aluminum and smelting-related contaminants, wherein the heating of the blank is a heating rate of greater than 4 K/s, the quenching of the blank is at a cooling rate of greater than 10 K/s, and cold forming of the motor vehicle component is performed within less than 50 seconds after the heating.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages, features, properties, and aspects of the present disclosure are the subject matter of the following description. Design variants are illustrated in schematic figures. These figures are used for simpler comprehension of the disclosure. In the figures:

(2) FIG. 1 shows an arrangement for carrying out the method according to the disclosure having a tempering station and a forming and trimming station according to at least one embodiment,

(3) FIG. 2 shows an alternative arrangement to FIG. 1 according to at least one embodiment,

(4) FIG. 3 shows an alternative arrangement to FIG. 1 according to at least one embodiment,

(5) FIG. 4 shows an alternative arrangement to FIG. 1 according to at least one embodiment, and

(6) FIGS. 5 to 7 show metallurgical microsections according to at least one embodiment.

(7) In the figures, the same reference signs are used for identical or similar components, even if a repeated description is omitted for reasons of simplification.

DETAILED DESCRIPTION

(8) FIG. 1 shows an arrangement 1 for carrying out the method according to the disclosure. The arrangement 1 comprises a combined tempering station 2. In a first step I, a heating procedure takes place. For this purpose, contact plates 3 are provided, which are heated via a heat source (not shown in greater detail) and heat the inserted blank 16 via heat conduction by means of facility contact. Hereafter, a blank inserted in the respective step is also shown for reasons of simplification. A second step II provides cooling plates 4. The cooling plates 4 comprise cooling ducts 5 for conducting through a coolant fluid. The heated blank is thus cooled in the second step by facility contact. Both the contact plates 3 and also the cooling plates 4 are each mounted via springs 6. The effective contact time can be lengthened in this way during the tool closing time and/or execution of the cycle, since the plates protrude in the tool closing direction. The contact pressure is also homogenized and a press deflection is compensated for. A lubricating facility 17 is optionally provided after the quenching, which applies a lubricant to the blank by means of spraying, for example.

(9) The blank heated in the first step I and quenched in the second step II is then transferred in a third step III in a forming station 12. A forming tool 7 is provided here, for a first forming of the motor vehicle component 8 to be produced. A subsequent fourth step IV can also comprise a perforating and/or trimming tool 9 alternatively or additionally to a forming step. Alternatively or additionally, further forming can also take place in this combined perforating or trimming tool 9. At the end of the method, the formed motor vehicle component 8 is obtained, which is a motor vehicle component formed hat-shaped in cross section by way of example here. The motor vehicle component can be a motor vehicle column, a longitudinal beam or crossbeam, or another vehicle body component or structural component, alternatively also a chassis component, outer skin component, or add-on part on a motor vehicle. A transfer system for the further transport of the blank is not shown.

(10) FIG. 2 shows an alternative embodiment variant to FIG. 1. An arrangement 1 is also shown here which provides a heating station 10, a cooling station 11, and a forming station 12. Overall, a six-step tempering and forming process is carried out, wherein firstly heating is performed in the first two steps I+II in the heating station 10. This heated blank 16 is transferred to a cooling station 11 subsequently thereto and quenched in the cooling station 11 in step III and step IV. The heated and subsequently quenched blank 16 is then transferred in a fifth step V into a forming tool 7 and formed in at least one step here and also optionally formed once again and also trimmed and perforated in a sixth step VI. The application of lubricant takes place between steps IV and V, for example by means of spraying on both sides. This can be performed using the lubricating facility 17. A motor vehicle component 8 is obtained, which is also configured hat-shaped in cross section here by way of example.

(11) FIG. 3 shows an alternative arrangement thereto. A tempering station 2 is again provided here, which both heats and also cools. The process is shown in seven steps. The first four steps are carried out in the tempering station 2. For this purpose, heating is performed in step I and step II. A quenching procedure takes place in steps III and IV. The blank thus tempered is then transferred to a forming station 12 and formed and also trimmed and perforated here in three further steps V-VII. The application of lubricant is performed between step IV and V, for example by means of spraying on both sides.

(12) FIG. 4 shows an alternative design variant. A joint tempering and forming station 13 is illustrated here. This means all contact plates 3, cooling plates 4, forming tool 7, and perforating and trimming tools 9 are suspended and/or fixed on a press top part 14 and press bottom part 15. A closing movement of the tempering and forming station 13 thus causes all steps I-VII to be executed simultaneously. Springs 6 are again also provided here, so that the effective contact time of contact plates 3 and also cooling plates 4 is lengthened during the movement of, for example, top tool 14 toward bottom tool 15. A lubricating facility 17 is furthermore shown here in the first forming step V. It applies lubricant to the forming jaws 18 of the forming tools 7.

(13) FIG. 5 shows a metallurgical microsection of a blank made of the described aluminum alloy according to the disclosure in the provided state. A laminar structure can be seen here.

(14) If rapid heating with subsequent quenching according to the disclosure is now carried out, the material microstructure shown in FIG. 6 is thus provided. It can be seen here that individual grains have formed which each have a grain size between 20 and 50 μm. The size specification relates to both a length and width extension in the image plane, and also a height extension into the image plane or out of the image plane. The grain size is thus formed equiaxially. After the subsequent forming, the grain size is formed essentially equal. The orientation of the grains is slightly distorted depending on the stretching occurring within the wall thickness during the forming procedure.

(15) In contrast thereto, FIG. 7 shows a material microstructure as was produced using slower and longer lasting heating and also slower and longer lasting cooling, over multiple minutes in each case. It can be seen that a significantly larger grain size and also different grain structure than in FIG. 6 results.

(16) The foregoing description of some embodiments of the disclosure has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed, and modifications and variations are possible in light of the above teachings. The specifically described embodiments explain the principles and practical applications to enable one ordinarily skilled in the art to utilize various embodiments and with various modifications as are suited to the particular use contemplated. It should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the disclosure.