Predicting of the Lüders’ bands in the processing of TH material in computer environment by means of stochastic modeling

The presented work focus on the investigation of the Lüders’ bands (hereafter referred to as LB) phenomenon in the computer environment by means of experimental design and stochastic modeling. In this investigation LB emerges in the TH materials processing, i.e. stamping process. In the production of TH materials the problem of Lüders’ banding has not been eliminated by the use of a skin pass or roller leveling (because of the tinning process) and is not always overcome by the use of interstitial free steel. Because of that, it is useful to predict LB occurrence before the expensive processing process. On the basis of identified input parameters by means of Box-Vilson's method, an experimental foundation for these investigations has been developed. This basis serves as a fundament for stochastic modeling. By means of stochastic modeling a computer procedure has been developed which will, in the production of practical work, enable the prediction of LB geometrical features (l  : length, ww: width and d: depth of LB) of predetermined workpieces. The geometrical features of LB originated after varying the input parameters, important in experimental design and stochastic modeling, have been evaluated with instruments for mechanical 3D measurement (Form Talysurf Series 2) as well as for optical 3D digitalization (ZKM 01-250C). The applicability and efficiency of the presented method have been proven by performing the experiment.