Numerical modeling method for improving morphology simulation precision of continuous laser deep penetration welding molten pool

Abstract

The invention discloses a numerical modeling method for improving the morphology simulation precision of a continuous laser deep penetration welding molten pool, and belongs to the technical field of numerical simulation in the welding process. According to the method, a continuous laser penetration fusion welding process is processed into a heat transfer-flow-phase change coupling problem containing solid, liquid and gas phases, and a transient three-dimensional incompressible multiphase flow model is established. According to the model, a high-frequency pulse laser heat source model with the frequency of 5000 Hz is adopted for simulating the continuous welding process, Rayleigh scattering, Fresnel absorption and liquid phase evaporation recoil pressure effects are considered, a THINC-Level Set method and a light beam tracking method are adopted for capturing a gas-liquid free interface, and the laser heating position is determined. In addition, a Gaussian surface heat source is added to equivalently calculate the heating effect of high-temperature plume on the surface of the molten pool, so that the heat transfer and mass transfer phenomena of the molten pool and a keyhole in the welding process are more truly represented, and the weld contour size prediction precision is improved. The method has positive significance in deepening the research of a high-frequency pulse laser penetration fusion welding mechanism and guiding the formulation and optimization of process parameters.

Description

technical field [0001] The present invention proposes a numerical modeling method for improving the simulation accuracy of molten pool shape in continuous laser deep penetration welding, which belongs to the technical field of numerical simulation of welding process, and is suitable for simulating heat transfer and mass transfer behavior in the process of high frequency pulse laser deep penetration welding. Background technique [0002] Welding is one of the most important types of work in the manufacturing industry and is widely used in industries such as automobiles, rail vehicles, aerospace, energy, ships, and microelectronics. Compared with the traditional arc welding method, laser deep penetration welding has the advantages of small heat-affected zone, fast welding speed, good welding quality, and good processing flexibility. A large number of studies have shown that there are complex multiphase flow and multiphysical field coupling phenomena in the laser deep penetrati...

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Problems solved by technology

[0004] However, traditional laser welding numerical simulations mostly use simplified heat source models such as preset keyhole walls or rotating Gaussian bodies, which cannot reflect the real spatial energy distribution of the laser beam and its thermal effect on the workpiece.

In addition, when simulating the continuous laser welding process, the constant laser power is usually used, ignoring the nature of its high-frequency pulse (frequency is 10 3 ~10 6 Hz), which reduces the rationality of modeling and the accuracy of simulation

In addition, there are few numerical simulation studies on the heat transfer and mass transfer aspects of the high-frequency pulsed laser deep penetration welding process.

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