Accuracy of calculated component distortions using the weld pool length to calibrate the heat source

Abstract

A better understanding of the laser welding process is fundamental for improving the quality of welded components. Hence, an experimental analysis, as well as an increase of the accuracy of computational approaches is important. When using a structural simulation to predict the component distortions caused by a welding process, it is necessary to reconstruct the temperature field. The use of heat source models is an established approach for the reconstruction of the temperature. This work is focused on evaluating the accuracy of calculated component distortions using the weld pool length to calibrate the heat source. For the implementation, image processing tools and an automated algorithm to calibrate the heat source are used. The experiments were carried out using an adapted intensity distribution which results from superimposing the beams of a high-power diode laser and a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser. To observe the process in general and the weld pool in particular, a high-speed camera was used. The image data was subsequently analyzed by an algorithm to extract the transient weld pool length. To simulate the laser welding process in an FEA-tool, a parameter calibration of two double ellipsoid heat sources, based on optimization algorithms, was used. To compare the computational and the experimental results, the component distortions were measured by position sensors. The results of the study are shown and the relevance of implementing the weld pool length to calibrate the heat source is pointed out.

Numerical Investigations on Residual Stress in Laser Penetration Welding Process of Ultrafine‐Grained Steel

“…As shown in Figure 5(b), the trace points P 1 , P 2 , P 3 , and P 4 were set to collect the residual stress and temperature information in the molten pool. e characteristics of the laser welding heat source were the local concentration and the instantaneous and heterogeneous temperature field, and an accurate heat source model can improve the accuracy of the FE simulation results [25]. A compound heat source model comprising a cone heat source and Gaussian surface heat source was adopted in this study, and the accurate heat source model was obtained through careful collation from the surface to the root of the weld between the FEA model and the cross section of the weld bead.…”

Simulação numérica e experimental de soldagem em operação de um aço API 5L X80 com processo GMAW.

“…Soldabilidade A soldabilidade de um material pode ser definida como "a capacidade que este mesmo material possui de ser soldado sob as condições impostas pelos códigos enormes de fabricação para uma estrutura específica e de forma aceitável e com desempenho satisfatório nos serviços pretendidos[52].Nascimento et al[55] verificaram que o método da potência instantânea média é o mais adequado para o cálculo da potência utilizada nos processos de soldagem.Deve-se ao pioneirismo do Prof. Dr. Daniel Rosenthal, o primeiro modelo matemático capaz de representar a distribuição de temperaturas no ano de 1935 primeiramente em Francês e em seguida traduzido e republicado na língua inglesa no ano de 1941[60], com análise adicional da distribuição de temperatura no processo oxicorte. Além disso, neste intervalo de tempo em 1938, Rosenthal e Schmerber publicaram um trabalho no qual apresentam a validação experimental das equações analíticas propostas[61].O modelo de Rosenthal[60] exibe derivações e afirmações claras das hipóteses simplificadoras. Além disso, são apresentadas equações para o cálculo das taxas de resfriamento do processo de soldagem.…”