Method for Manufacturing a Component

Abstract

A method for manufacturing a component from a hardenable aluminum alloy includes the steps of: heating a blank to a predefined temperature; shaping the heated blank into a semifinished product in a shaping tool; cooling the semifinished product during or following the shaping process; and shaping the cooled semifinished product into a component in a second shaping tool.

Description

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a method for manufacturing a component from a hardenable aluminum alloy.

Four fundamentally different methods have been established for forming aluminum. In the case of cold forming in the so-called T4 state, forming an aluminum plate is performed in a soft state. The component is thereafter hardened by artificial aging. In the case of W temper forming and forming in the W state, an aluminum plate is initially solution annealed, subsequently quenched, and immediately formed in the very soft state. Artificial aging for hardening the material can also follow this. In the case of so-called warm forming, a hardened material is heated to approximately 200 to 250° C. and is formed in this warm and softened state. Moreover, hot forming in which a hardenable alloy is heated to temperatures beyond 400° C. and is formed in a cold or hot forming tool is also known. In the forming of the hot aluminum sheet in the cold tool, a very soft state of the formed sheet results, similar to that of the state in W temper forming.

The W temper forming method sets higher requirements in terms of the process management of the systems technology, since the components have to be formed in a tight temporal process window after the heat treatment. The degrees of deformation that are achievable are comparatively small when compared to hot forming.

A method for manufacturing an aluminum formed part is known from DE 10 2008 032 911 A1. This method includes the following steps: placing an aluminum sheet in a forming tool; partially forming the aluminum sheet to a partially formed aluminum sheet at room temperature; artificially aging the partially formed aluminum sheet; and subsequently finally forming the partially formed aluminum sheet into a final shape of the aluminum formed part at room temperature.

A further method for manufacturing an aluminum formed part is known from DE 10 2012 007 213. According to a first embodiment, an aluminum plate that is to be formed is heated and formed in a cooled forming tool while being simultaneously quenched. According to a second embodiment, the aluminum plate after heating is quenched, provided with a lubricant, and formed in the cold state in a forming tool.

Proceeding from this prior art, the present invention is based on the object of specifying a method for manufacturing a component by way of which the disadvantages of the prior art are overcome. It is a particular object of the invention to state a method by way of which the highest possible degrees of deformation can be achieved. It is moreover an object of the invention to specify a method which is distinguished by high cycle rates, or by a high simplification in terms of method technology, respectively.

These and other objects are achieved by a method for manufacturing a component from a hardenable aluminum alloy, the method comprising the steps of: heating a blank to a predetermined temperature; forming the heated blank to a semi-finished product in a forming tool; cooling the semi-finished product, wherein cooling is performed after forming or during forming; and forming the cooled semi-finished product to a component in a second forming tool.

In order for the object to be achieved, the invention proposes a method for manufacturing a component from a hardenable aluminum alloy. Hardenable aluminum alloys in the context of the invention are so-called 7000 alloys or 6000 alloys as well as all further alloys which can achieve high strength values by hardening. In a first step of the method a blank is heated to a predetermined temperature. Blanks are to be understood, for example, as aluminum plates which have previously been severed from an aluminum coil. Of course, blanks can also be plates having a predetermined shape which are adapted to the final shape of the finished component to be obtained. The blank is heated to a predetermined temperature in the range from 450 to 550° C., in particular 500° C. According to a first embodiment, the heated blank is formed in a cold tool, wherein the blank when formed to the semi-finished product is simultaneously cooled. According to a second embodiment of the invention, the heated blank is initially cooled and then formed in the forming tool. In both embodiments described, cooling or quenching, respectively, is performed to the ambient temperature. The ambient temperature here is in a range from 5 to 50° C. The semi-finished product after forming is present in a so-called W state. The blank in this state has a soft material structure.

The core concept of the invention is that in this state immediate forming in the cold state can follow without the component having to be solution annealed. By forming the cooled semi-finished product in a second forming tool, almost the final shape of the component is generated. A semi-finished product in the context of the invention is a formed part that is shaped in two or three dimensions. A component in the context of the invention is a formed part which is likewise curved in two or three dimensions, the geometric shape and contour of said formed part corresponding substantially to the finished component. In other words, after the second forming only minor machining (or no machining at all) is required in order to obtain the final shape of the component. However, of course, bores can still be incorporated, coatings applied, or minor trimming performed on the component by post-machining.

Moreover, the heated blank can be formed to the semi-finished product in a preliminary forming step, and the cooled and pre-formed semi-finished product can be finally formed to a component in a second forming step that, in terms of the contour, is close to the final contour. Very high degrees of deformation can be realized when pre-forming in the heated state, without solidifications arising in the material. Only minor adaptations in terms of shape, in which the risk of solidifications in the material of the component is comparatively minor, are implemented in the case of the second forming that in terms of the contour is close to the final contour. By combining hot forming in a first forming stage, wherein the warm material is formed in a cold tool, and, directly following this, forming in the W state as a second forming stage, the material of the aluminum sheet leaves the first forming stage in the W state, the latter in technical terms being able to be utilized for the second forming stage. This offers the advantage that an additional heat treatment which is otherwise required for the forming method in the W state, is eliminated. The forming capability of the material can thus be utilized in an optimal manner, and the manufacturing method can be shortened by one heating step. The so-called W state is defined in EN-515:2000 as the state directly after the annealing solution and quenching, and represents an unstable state, since the elongation at break/formability decreases on account of the storage at room temperature.

Furthermore, the cooled blank prior to forming in the second forming tool can be in a W state.

Furthermore, the component in a following method step can be hardened by a heat treatment. A heat treatment of this type can be performed in the form of artificial aging, for example. The component herein is heated to a temperature in the range from 80 to 250° C., preferably however to 200° C. and is kept at this temperature for two hours. On account thereof, the component is transformed to a so-called T6 state or a so-called T7 state. The states T6 and T7 are likewise defined in EN-515:2000.

Trimming of the pre-formed component or of the blank is preferably performed prior to the hardening of the formed semi-finished component. The blank, or the pre-formed semi-finished product, herein can be trimmed to a contour that is close to the final contour. This offers the advantage that the trimming is performed in a comparatively soft state. As opposed to trimming of the finished, that is to say the hardened, component there is the advantage that the wear on the trimming tools can be substantially reduced.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In a schematic, simplified illustration herein:

FIG. 1 shows the method step of heating.

FIG. 2 shows the method step of first forming.

FIG. 3 shows the pre-formed semi-finished product.

FIG. 4 shows the method step of second forming.

FIG. 5 shows the method step of component hardening.

DETAILED DESCRIPTION OF THE DRAWINGS

As can be seen from FIG. 1, a pre-formed plate 10, with the aid of a heating installation 40, is heated to a predetermined temperature in the range of approx. 500° C.+/−10%. The heated blank 10 is incorporated into a first forming tool 20 which comprises an upper tool half 21 and a lower tool half 22. The two tool halves 21, 22 for closing are capable of being converged, and for opening are capable of being diverged. The heated blank 10 is formed to a semi-finished product 11 by closing the two tool halves 21, 22. High degrees of deformation are achieved herein such that the main forming work which is required for forming the blank 10 to the finished component 12 is already performed in the first forming step in the tool 20. The formed semi-finished product 11 herein can be quenched simultaneously with the forming in the forming tool 20.

Alternatively thereto, said formed semi-finished product 11 can be subsequently actively or passively cooled to room temperature, or to the ambient temperature, respectively, for example by air, as is illustrated in FIG. 3.

As soon as the formed semi-finished product 11 has been cooled, the latter is incorporated into a second forming tool 30. The latter, in a manner analogous to that of the first tool 20, likewise comprises an upper tool half 31 and a lower tool half 32 which are capable of being converged and diverged. The pre-formed semi-finished product 11 is shaped to the final contour of the finished component 12 by closing the tool halves 31 and 32. As can be seen from FIG. 4, only minor degrees of deformation are achieved herein. The component 12 formed to the final contour, or the component 12 that is formed only so as to be close to the final contour, respectively, is retrieved from the second forming tool 30 and is hardened with the aid of a heat treatment. This heat treatment, in which the component 12 with the aid of a second heating installation 50 is heated to a predetermined temperature, for example in the range from 180° C. to 250° C., is shown in FIG. 5. The finished component has predetermined strength properties once the component has been exposed to this temperature for a predetermined time, for example 2 hours.

On account of the above, an aluminum component, or an aluminum formed part which is hardened to the state T6 or T7, respectively, and is twice formed is created as a final product of the method. Higher degrees of deformation are achieved by the method, and components of which the geometry could not be reproduced by a single method step are produced on account of said method. Moreover, a cost optimization is performed by dispensing with a heat treatment stage which can be saved by virtue of the combination of processes.

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.

Claims

1. A method for manufacturing a component from a hardenable aluminum alloy, the method comprising the steps of: heating a blank to a predetermined temperature;forming the heated blank to a semi-finished product in a forming tool;cooling the semi-finished product, wherein cooling is performed after forming or during forming; andforming the cooled semi-finished product to a component in a second forming tool.

2. The method as claimed in claim 1, wherein the heated blank in a preliminary forming step is pre-formed to the semi-finished product; andthe cooled and pre-formed semi-finished product is finally formed to a component in a final forming step.

3. The method as claimed in claim 1, wherein the cooled semi-finished product prior to forming in the second forming tool is in a W state.

4. The method as claimed in claim 1, wherein the component is hardened by a heat treatment.

5. The method as claimed in claim 1, wherein trimming of the component, of the semi-finished product or of the blank is performed prior to hardening of the component.