P 939 - Simulation-based detection of humping and edge notches taking into account the temperature-dependent density in the melt pool

The simulation model used for the flow processes in the weld pool takes into account not only the temperature-dependent change in density, but also the movement of the liquid, free surface. With the extended flow model, it is possible to analyse the isolated influence of the individual parameters on the humping and the edge notches, as well as to determine the influence of different technical measures to avoid these undesirable effects. This makes it possible to predict the formation of humping or edge notches with greater accuracy. As a scientific and technical result of the project, parameter ranges for high welding speeds that enable a humping-free welding process were analysed based on the numerical investigation of the welding processes. By taking into account the temperature-dependent change in density, the model summarises all the important parameters for mapping the weld pool dynamics. This is the first time that a simulation of weld pool dynamics has been achieved that takes all the key physical parameters into account. Despite very good qualitative agreement, it was not possible to achieve sufficient quantitative agreement between the test and simulation results. The reason for this lies in the models used in the software intended for the project. Possible solutions are the use of alternative software solutions or a much finer meshing of the components for the simulation. Both options could not be realised within the scope of the project due to time constraints.