Methods for producing a component composite and component composite

Abstract

Method for producing a component composite (1) with reduced corrosion tendency, wherein a first component (2) and a second component (3) are welded together by forming a fillet weld (4), characterized by the fact that the front fillet weld (4) is formed by tactile laser welding, and that a joint area (5) to be smoothed, which includes the butt joint (4) and component sections (6, 7) adjoining it on both sides, is melted at least superficially in such a way that the surface in the smoothed area (5A) has a continuous profile and transitions seamlessly into adjacent unsmoothed areas, where the smoothed connection area (5A) has a mean roughness value of 3 µm or less.

Description

[0001] The invention relates to a method for producing a component composite and to a component composite.

[0002] Welding is an established process for creating composite components. In this process, the material of the components to be joined is melted by the application of energy. The molten material mixes and cools to form a weld, which creates a metallurgical bond between the components. Welding can be performed with or without filler material. For welded joints in vehicle construction, butt welds are frequently used. A butt weld is a welded joint between two components, where an upper component rests at least partially overlapping a lower component, and the weld is formed between at least one edge or flank surface of the upper component and the adjacent bearing surface of the lower component. Such a weld can also be referred to as a flank fillet weld. The butt weld can be a continuous weld or a stitched weld (i.e., with interruptions in the weld).

[0003] From EP 1 175 955 A2, a method for smoothing a weld root and / or a weld bead is known. From DE 10 2014 203 025 A1, a method is known which provides for integrating the formation of a weld and the post-processing of the weld into a single process step. From DE 10 2013 219 220 A1, a method for forming a fillet weld by means of a laser remote processing method is known.

[0004] In addition to the strength of the weld, it is of enormous importance in the automotive industry that the joint has a low tendency to corrode.

[0005] While it is common practice to subsequently apply an anti-corrosion sealant, such as a cathodic dip coating (KTL coating), depending on the nature of the weld, this may require further processing of the components, such as additional cleaning.

[0006] Against this background, the object of the present invention is to demonstrate a way in which the tendency to corrosion in a component composite can be reduced reliably and using simple means.

[0007] The problem is solved by a method according to claim 1 and a component assembly according to claim 6. Further advantageous embodiments are described in the dependent claims and the following description.

[0008] A method is described in which at least a first and a second component are welded together by forming a fillet weld. According to the invention, after the fillet weld has been formed, at least a superficial remelting, smoothing, and cleaning (removal of contaminants, e.g., soot) of a joint area of ​​the components is carried out. The fillet weld is formed by tactile laser welding. The joint area comprises the fillet weld as well as the component sections of the first and second components adjacent to the fillet weld. The width of the component sections in which smoothing / cleaning takes place can vary and is preferably selected such that edges and burn marks are remelted. The remelting and smoothing is carried out in such a way that the joint area is free of edges and steps.

[0009] In particular, the surface of the smoothed joint area exhibits a continuous profile and transitions smoothly into the surface of the unsmoothed component sections adjacent to the joint area. The smoothed joint area has a mean roughness value of 3 µm or less.

[0010] For smoothing, the fillet weld and the adjacent component sections (viewed in the weld direction) are surface-melted. The weld itself is smoothed, cleaned of contaminants, and a smooth, edge-free transition from the components to the weld is created. In particular, the upper sheet metal component is rounded in the edge area by the smoothing process. Smoothing is also performed on the side of the lower sheet metal component. This not only creates a smooth transition between the component and the weld but also has a cleaning effect, removing, for example, soot residue from the previous weld.

[0011] It has been found that such a smoothed component contour exhibits a significantly reduced tendency to corrosion and, in particular, filiform corrosion can be suppressed or greatly reduced.

[0012] A particularly high surface quality of the smoothed area can be achieved if, in a preferred embodiment, the melting or smoothing is carried out using a laser beam that is oscillated and defocused over the area to be smoothed. The energy input is selected to achieve the desired degree or depth of melting. The focus can be set above or below the joining plane. The oscillation pattern is not limited to a specific shape and can be, for example, sinusoidal, circular, or any other shape. It is apparent to those skilled in the art that, with a suitable selection of the welding and oscillation parameters, the melting and smoothing can also be performed with a focused laser beam.

[0013] It can be advantageous to smooth a joint area that has a width at least twice the weld width. For example, component sections to the right and left of the fillet weld can be smoothed to a width of at least half the fillet weld width.

[0014] To prevent fissure corrosion, it has proven particularly advantageous if the smoothed component and seam surfaces have a mean roughness value R. A exhibiting dimensions of 3 µm (micrometers) or less.

[0015] Due to the high processing speeds achievable, smoothing is particularly advantageous when performed using a scanner-based remote laser beam system. In remote laser beam welding, a high-energy laser beam with a long focal length, e.g., more than 30 cm, is directed at the components. Scanner-based remote laser beam systems also feature scanner optics for beam deflection, which, by means of adjustable mirrors, enable highly dynamic positioning of the laser beam. If such scanner-based remote laser systems are operated "on the fly," meaning the scanner optics can also be positioned by a robot, working speeds of up to 9 m / min and beyond can be achieved.

[0016] This process is particularly suitable for joining materials that typically form a weld seam with poor surface quality. In a preferred embodiment, the process is used to join aluminum components, including those made of aluminum alloys.

[0017] Furthermore, a component assembly is described, consisting of a first component and a second component welded together by means of a fillet weld. The fillet weld is formed by tactile laser welding. In a joint area that includes both the fillet weld and laterally adjacent sections (viewed in the longitudinal direction of the fillet weld) of the first and second components, the surface of the component assembly is smoothed by melting, so that the surface in the joint area has a continuous profile and transitions seamlessly into the unsmoothed areas. The surface in the smoothed joint area has a mean roughness of less than 3 µm. The components are aluminum components.

[0018] The component assembly is preferably manufactured using the method described above and, as such, achieves the same technical effects and advantages described for the method.

[0019] The components are preferably sheet metal parts, which can be either flat sheet metal sections or three-dimensionally shaped sheets (sheet metal forming parts). Thin sheets with a thickness of less than 3 mm are preferably used.

[0020] In principle, all weldable materials or combinations are suitable for the sheet metal components, such as steel sheets (with and without corrosion protection) or sheets made of aluminum or magnesium alloys. However, the process offers particular advantages when the sheet metal components are made of an aluminum alloy, and especially of 5000 or 6000 series aluminum alloys, which tend to have scaly weld surfaces and are therefore generally difficult to process.

[0021] The component composite produced by this method exhibits a significantly reduced tendency to corrosion. Therefore, the method is particularly suitable for producing component composites that require high corrosion resistance. In a preferred embodiment, the method is used to produce a component composite that is a body panel or body attachment, for example, a vehicle door or a vehicle hatch.

[0022] The properties, features, and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more easily understood with reference to the drawing and in conjunction with the following description of exemplary embodiments. Where the term "may" is used in this application, it refers to both the technical possibility and the actual technical implementation.

[0023] The following are examples of implementation explained with reference to the accompanying drawings. These show: Fig. 1 a schematic representation of a component composite with a formed butt joint, which is already partially smoothed, Fig. 2 a sectional view of the unsmoothed front fillet weld from Fig. 1, Fig. 3 a sectional view of the component assembly made of Fig. 1 with already smoothed connection area.

[0024] Based on the in Fig. The present invention is explained with reference to the component assembly shown in Figure 1.

[0025] A first component 2 is welded to a second component 3 by a butt weld 4. Components 2 and 3 could, for example, be an inner and an outer panel of a vehicle door.

[0026] The fillet weld 4 runs along the end face of the first component 2 and can, for example, have a spatially or plane-curved profile. The upper and lower sheets 2, 3 can also be joined together by several fillet welds. The fillet welds can be formed using conventional methods, with and without filler material. Forming the fillet weld by tactile laser welding has proven particularly effective, whereby the position of the laser beam is guided by a tactile weld guidance system that traces its path along the fillet like a sensor.

[0027] After forming the butt weld 4, a laser beam L from a laser remote device is now directed onto the joint area 5 to be smoothed (indicated by the dashed lines in Fig. 1) directed and guided along it. The connection area 5 comprises the weld 4, as well as a component section 6 of the first component 2 adjacent to the weld and a component section 7 of the second component 3.

[0028] The laser beam L is guided over the joint area, causing surface melting of the material of the weld seam 4 and the adjacent component sections 6 and 7. The laser beam L is used as a defocused beam, meaning its focus is significantly above or below the weld seam plane, thus reducing the energy density coupled into the components. The resulting relatively large laser spot is additionally moved across the components in an oscillating motion, as indicated by arrow O in the figure. Fig. 1. The oscillation O superimposed on the feed motion V of the laser beam L can have any desired shape, e.g., a circular or sinusoidal oscillation, or other shapes. By using a scanner-based remote laser system, the melting process can be carried out very quickly, e.g., at operating speeds of up to 9 m / min.

[0029] The surface melting caused by the laser beam L leads to a smoothing of the weld area and an alignment of the topography of components 2 and 3 in the joining area 5. As a result, the joining area located behind the laser beam L in the feed direction is a smoothed area 5A. In particular, the width of the joining area 5 is selected such that an edge of the top sheet is completely melted and a rounded, edge- and step-free transition is formed between the weld 4 and the first component or top sheet 2. The joining area 5 has, for example, a width that is at least twice the weld width; thus, for example, a strip with at least half the width of the weld 4 is smoothed to the right and left of the weld. The molten material also flows partially towards the second component 3.The laser beam smoothing process smooths the transition between the end weld 4 and the bottom sheet 3. Additionally, it cleans the surface of soot marks and other contaminants.

[0030] The resulting component assembly 1 is characterized by a butt weld 4 with a very smooth surface and a continuous, i.e., edge- and step-free, surface profile in the area of ​​the connection section 5. The tendency for corrosion is significantly reduced, and the durability of corrosion protection coatings applied in subsequent processing steps is also improved on the smoothed surface. Fig. 2 and Fig. Figure 3 additionally shows a cross-sectional view of the frontal seam before smoothing ( Fig. 2) and after smoothing ( Fig. 3). In Fig. Figure 3 also shows the oscillation of the laser beam L with the maximum deflections.

[0031] The examples shown are not to scale and are not limiting. Variations within the scope of professional practice are possible. Reference symbol list 1 Component composite 2, 3 components 4 Forehead suture 5 Connection area 5A smoothed connection area 6, 7 Component section O Oscillation movement L laser beam V Feed direction

Claims

[1] Method for producing a component composite (1) with reduced corrosion tendency, wherein a first component (2) and a second component (3) are welded together by forming a fillet weld (4), characterized by , that the front fillet weld (4) is formed by tactile laser welding, and that a joint area (5) to be smoothed, which includes the butt joint (4) and component sections (6, 7) adjoining it on both sides, is melted at least superficially in such a way that the surface in the smoothed area (5A) has a continuous profile and transitions seamlessly into adjacent unsmoothed areas, where the smoothed connection area (5A) has a mean roughness value of 3 µm or less. [2] Method according to claim 1, wherein the smoothing is carried out by means of a laser beam (L) which is oscillating and defocused over the joint area (5) to be smoothed. [3] Method according to claim 1 or 2, wherein the smoothed joint area (5A) has a width that is at least twice the weld width. [4] Method according to any one of claims 1 to 3, wherein the smoothing is carried out using a scanner-based remote laser beam device. [5] Method according to any one of claims 1 to 4, wherein the components (2, 3) are aluminium components. [6] Component composite with a first component (2) and a second component (3), which are welded together by means of a fillet weld (4), characterized by , that the front fillet weld (4) is formed by tactile laser welding, and that the surface of the component composite (1) in a connection area (5A), which includes both the butt joint (4) and laterally adjacent sections (6, 7) of the first and second component (2, 3), is smoothed by melting in such a way that the surface in the connection area (5A) has a continuous profile and transitions seamlessly into adjacent unsmoothed areas, wherein the surface in the smoothed connection area (5A) has a mean roughness value of less than 3 µm, and where the components (2, 3) are aluminium components. [7] Component assembly according to claim 6, wherein the components (2, 3) are body components or body add-on parts. [8] Component assembly according to one of claims 6 to 7, which is a vehicle door or a vehicle flap.

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