Considering fluctuations of material properties, stainless steel 1.4301, on manufacturability of kitchen sinks

In production of deep drawn sheet metal parts, it is often challenging to achieve a robust process. Especially in the production of kitchen sinks made out of stainless steel, the fluctuation of the process and material properties often lead to robustness problems. Therefore, numerical simulations are used to detect critical regions. To keep a constant product quality, process control is realised based on metamodels, which are computed by means of a series of finite element simulations. In order to enhance the forecast capability of the simulation model and to increase the reliability of quality features, the yield curve, the yield locus and the forming limit curve (FLC) of different suppliers are measured with tensile, bulge and Nakazima experiments. Because of the large deformation capability of stainless steels, large drawing depths can be achieved. However, the classic Nakazima geometries are not distributed homogenously in the forming limit diagram (FLD). To overcome this shortcoming, a shape optimization of the Nakazima specimen has been performed. Furthermore the influence of alloying elements on the hardening behaviour and on the FLC are analysed. In addition, the measured FLC-T (temperature dependent FLC) conducted with heated Nakazima tests is compared with the computed FLC-T with the modified maximum force criterion (MMFC).