Study of asymmetric rolling to improve textures and r-values of aluminium deep drawing alloys

© 2018 Trans Tech Publications, Switzerland. The typical textures developed in aluminium alloys for deep drawing applications are less favourable as those in competing steel sheet material. The {111} fibre texture in steel, associated to high r-values, is favourable to this purpose, but the typical textures of the aluminium materials, the {001}<100> "cube" texture component and the β-fibre component, are not. Asymmetric rolling (ASR) as part of the production process generates a shear component at the expense of the unfavourable components. Modelling was tried out as a possible tool to fine-tune the process parameters. A multiscale FEM model (with a built-in polycrystal deformation model to predict the texture) was used to this purpose. The effect of the shear component on the resulting texture is discussed in function of the values of the process variables, as well as its effect on the resulting plastic anisotropy parameters (r and q values).Limiting Drawing Ratio (LDR). Fig. 1 in [2] illustrates a cup drawing test as those used to characterize the deep drawability of a sheet material. The ‘drawing ratio’ is the ratio between the radius of the final cup and the radius of the circular blank (fig. 1f in [2]). The higher this ratio, the larger the strain. Most of it is applied to the flange (Fig. 1b in [2]). An analysis of the deformation process would reveal that at a given point in the flange, the local strain mode is approximately similar to that of an axial compression test in circumferential direction, the radius shrinking as the blank gets drawn in. The force driving this deep drawing process has however to be transmitted from the punch to the flange by the wall (see Fig. 1b-c in [2]). The process fails when the wall is not.

ISBN:9783035712087

Publication year:2018

BOF-keylabel:yes

IOF-keylabel:yes

Authors from:Higher Education