Simulation of the influence of electromagnetic stirring during laser beam welding of thick-walled steel components with filler material
Final Report Abstract
The insufficient material mixing and the resultant inhomogeneous element distribution in the final weld is a common issue for the high-power laser beam welding (LBW) with additional filler materials. In recent years, the magnetohydrodynamic (MHD) technique through applying an external magnetic field is considered as a promising way to overcome this issue. However, the fundamental mechanism of this process is still not fully revealed due to the extremely complicated multi-coupled phenomena involved. The objectives of this DFG project are to investigate the enhancement of material mixing quantitatively and systematically in the electromagnetic stirring enhanced wire feed laser beam welding by using a combination of experimental and multi-physical modelling approaches. Therefore, a three-dimensional transient CFD model is developed to calculate the heat transfer, fluid flow, keyhole dynamics, element transport as well as electromagnetic behaviors (induced eddy current and Lorentz force). An advanced ray-tracing algorithm with virtual refinement is proposed to calculate the spatial laser energy distribution on the keyhole wall by considering the multiple reflections and Fresnel absorption. The model is well experimentally verified. The obtained results suggest that the Lorentz force produced by an oscillating magnetic field shows an important influence on the thermo-fluid flow and the keyhole stability. The additional elements from the filler material are significantly homogenized because of the enhanced forward and downward flow in the weld pool. Under the same frequency, the magnetic field with smaller angle with respect to the transverse direction provides better penetration capacity, and its stirring effect can reach the lower part of the molten pool, which achieves a better material mixing. Additionally, the grain refinement from the electromagnetic stirring is also confirmed by electron backscatter diffraction analysis. Through the decoupling based on the numerical model, it is found that the dendrite fragmentation, rather than the change in temperature gradient and solidification rate, dominates the grain refinement. In further study, an untypical weld pool profile, i.e., elongated at the top and bottom but narrowed at the middle, is found experimentally by real-time metal/glass observation and numerically by multi-physical modeling for the first time, which bring further detrimental influence not only on the material mixing but also on the porosity defect formation. The introduction of the external magnetic field can effectively eliminate this weld pool profile, thereby a widened channel for the downward element transfer and bubble escaping is obtained. The results of the research project have been published in several peer-reviewed journals and presented in conferences of welding and laser processing. Especially, one recent paper wins the "IIW Kenneth Easterling Award" at the 13th International Seminar "Numerical Analysis of Weldability" in Seggau, Austria.
Publications
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Experimental and numerical assessment of weld pool behavior and final microstructure in wire feed laser beam welding with electromagnetic stirring. Journal of Manufacturing Processes, 45, 408-418.
Meng, Xiangmeng; Bachmann, Marcel; Artinov, Antoni & Rethmeier, Michael
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Numerical and experimental investigation of thermo-fluid flow and element transport in electromagnetic stirring enhanced wire feed laser beam welding. International Journal of Heat and Mass Transfer, 144, 118663.
Meng, Xiangmeng; Artinov, Antoni; Bachmann, Marcel & Rethmeier, Michael
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Numerical study of additional element transport in wire feed laser beam welding. Procedia CIRP, 94, 722-725.
Meng, Xiangmeng; Artinov, Antoni; Bachmann, Marcel & Rethmeier, Michael
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Theoretical study of influence of electromagnetic stirring on transport phenomena in wire feed laser beam welding. Journal of Laser Applications, 32(2).
Meng, Xiangmeng; Artinov, Antoni; Bachmann, Marcel & Rethmeier, Michael
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The influence of magnetic field orientation on metal mixing in electromagnetic stirring enhanced wire feed laser beam welding. Journal of Materials Processing Technology, 294, 117135.
Meng, Xiangmeng; Bachmann, Marcel; Artinov, Antoni & Rethmeier, Michael
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"An investigation of keyhole dynamics and porosity mitigation in laser beam welding with external magnetic field " In: IIW Annual Assembly, Osaka, Japan, 2022
Meng, X., Bachmann, M., Artinov, A. & Rethmeier, M.
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A study of the magnetohydrodynamic effect on keyhole dynamics and defect mitigation in laser beam welding. Journal of Materials Processing Technology, 307, 117636.
Meng, Xiangmeng; Bachmann, Marcel; Artinov, Antoni & Rethmeier, Michael
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Elucidation of the Bulging Effect by an Improved Ray‐Tracing Algorithm in Deep Penetration Wire Feed Laser Beam Welding and Its Influence on the Mixing Behavior. Advanced Engineering Materials, 24(6).
Bachmann, Marcel; Meng, Xiangmeng; Artinov, Antoni & Rethmeier, Michael
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Evaluation of narrowed weld pool shapes and their effect on resulting potential defects during deep penetration laser beam welding. Journal of Laser Applications, 34(4).
Bachmann, Marcel; Meng, Xiangmeng; Artinov, Antoni & Rethmeier, Michael
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Influence of the free surface reconstruction on the spatial laser energy distribution in high power laser beam welding modeling. Journal of Laser Applications, 34(4).
Meng, Xiangmeng; Putra, Stephen Nugraha; Bachmann, Marcel; Artinov, Antoni & Rethmeier, Michael
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Study on the transition behavior of the bulging effect during deep penetration laser beam welding. International Journal of Heat and Mass Transfer, 184, 122171.
Artinov, Antoni; Meng, Xiangmeng; Bachmann, Marcel & Rethmeier, Michael
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The detrimental molten pool narrowing phenomenon in wire feed laser beam welding and its suppression by magnetohydrodynamic technique. International Journal of Heat and Mass Transfer, 193, 122913.
Meng, Xiangmeng; Artinov, Antoni; Bachmann, Marcel; Üstündağ, Ömer; Gumenyuk, Andrey & Rethmeier, Michael
