Fostabericht P 939 - Simulationsgestützte Erfassung von Humping und Randkerben unter Berücksichtigung der temperaturabhängigen Dichte im SchmelzbadFostabericht P 939 - Simulationsgestützte Erfassung von Humping und Randkerben unter Berücksichtigung der temperaturabhängigen Dichte im Schmelzbad

P 939 – Simulation of humping effects and undercuts in consideration of the temperature-dependent density in the molten pool

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P 939 – Simulation of humping effects and undercuts in consideration of the temperature-dependent density in the molten pool

The modern beam methods like laser beam and electron beam welding allow for an exactly defined heat input, which plays an important role especially when welding challenging materials and material combinations. Through innovative beam sources, higher welding speeds are possible. With this, the intensity of the molten pool dynamics increases, which leads to weld defects. In this project, humping effects and the formation of edge grooves have been studied for the steel grades DC05 (1.0312) and X8CrMnNi19-6-3 (1.4376) on a simulation basis. Thereby the applied simulation model of the flow processes in the weld pool takes into account not only the temperature dependent density change, but also the movement of the liquid, free surface. With the extended flow model it is possible to examine the isolated influence of each individual parameter on humping and edge groove formations, as well as to determine the influence of different technical measures for preventing these unwanted effects. With this it is possible to make a more accurate prediction about the formation of humping or edge grooves. As a scientifictechnical result of this project, parameter ranges for high weld-ing speeds were examined based on the numerical analysis of welding processes which allow a humping-free welding process.
With the consideration of the temperature dependent density change, the model summarizes all significant parameters for the reproduction of the weld pool dynamics. In this way and for the first time a simulation of the weld pool dynamics has been achieved, that takes into account all significant physical magnitudes. Despite a good qualitative accordance, an acceptable quantitative accordance of experimental and simulation results couldn’t be achieved. The reason for this is the employed models of the software provided in this project. Possible solutions are the use of alternative software solutions or a substantially finer meshing of the components for the simulation. Both variants were not realizable within this project for time reasons.The research project (IGF-Nr. 17294 N) was carried out at Institut für Schweißtechnik und Fügetechnik der RWTH Aachen. FOSTA has accompanied the research project work and has organized the project funding from the Federal Ministry of Economics and Technolo-gy through the AiF as part of the pro-gramme for promoting industrial co-operation research (IGF) in accordance with a resolu-tion of the German parliament.

Only available in german language.

Published in:
January 2019