Papers by Keyword: EN AW-6060

Abstract: Precipitation hardening aluminium alloys are widely used for automotive applications. To enhance the application of aluminium profiles, improved formability is needed. Tailor Heat Treated Profiles (THTP) with locally different material properties attempt to increase formability e.g. in bending processes. Tailoring of local properties is obtained by a local short-term heat treatment, dissolving the initial precipitate state (retrogression) and still allowing subsequent ageing. In the present study, the dissolution and precipitation behaviour of the aluminium alloy EN AW-6060 T4 was investigated during heating with differential scanning calorimetry (DSC). Heating curves from 20 to 600 °C with heating rates of 0.01 up to 5 K/s were recorded. Interrupted heat treatments with different maximum temperatures were performed in a deformation dilatometer. Immediately afterwards, tensile tests were carried out at room temperature. The course of the recorded mechanical properties as a function of the maximum temperature is discussed with regard to the dissolution and precipitation behaviour during heating. Finally, the aging behaviour of the investigated alloy was recorded after different typical short-term heat treatments and is discussed with reference to the DSC‐curves. The correlation of the microstructure and the mechanical properties enables the derivation of optimal parameters for the development of THTP through a local softening.

Abstract: One of the decisive criteria in the selection of material between steel and aluminium could be the welding RS (residual stresses), which play an important role for the fatigue behavior of the structures under cycling loading. In the current paper simulations in commercial FE software ANSYS were carried out, in order to calculate the welding RS field for three different materials: structural steel S355 and the aluminum grades EN AW-6060 and EN AW-5754. In the case of EN AW-6060 influence of recrystallization on the yield strength of the HAZ (heat affected zone) was taken into consideration.

Abstract: On a global market, new products are subject to rising requirements regarding strength and quality. Simultaneously, the conservation of the environment and natural resources has become a key priority. One approach to these demands is the weight reduction of mechanical components by lightweight construction. The Transregional Collaborative Research Center (TR 10), funded by the German Research Foundation (DFG), is therefore working on the “Integration of forming, cutting and joining for the flexible production of lightweight space structures”. The use of light metals, like aluminium and composite materials is a main part in the TR10 process chain. This paper deals with the challenges of welding of light weight components made out of EN AW-6060. It shows the use and potentials of two innovative joining processes, particularly suited for welding aluminium. Especially developed for the fusion welding of aluminium components, BHLW (Bifocal Hybrid Laser Beam Welding), combines a Nd:YAG and a high power diode laser. The paper will give insight into the findings of the achieved results so far and line out the further proceedings with regard to critical parameters and their effect on the overall laser welding process. For the welding of aluminium composite materials, which play a big role in the TR10 process chain, Friction Stir Welding (FSW) is evaluated. As a solid state joining process, it can be used for the welding of materials that are hardly weldable with fusion welding techniques. In this paper, results of basic experiment for the joining of reinforced aluminium and the resulting process forces are presented.

Abstract: This paper renders research into the fundamentals governing the melt pool dynamics of a hybrid bifocal laser welding system consisting of an Nd:YAG and a high power diode laser (HPDL). The resulting superposition of keyhole by heat conduction mode welding is assayed for extruded aluminum. In particular the diffusion of the surface oxygen layer is considered. By comparing the results attainable by bifocal laser hybrid welding to the constituent laser processes synergetic effects of the laser hybrid can be demonstrated. These are namely the doubling of the welding speed from 2.0 min-1 to 4.0 m min-1, the reduction of the roughness of the weld surface from 60 om to approximately 10 om and an increase in energy transfer efficiency. The experimental investigations verifying these synergies are outlined and discussed.