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• A numerical model of laser cladding for V-grooves was constructed. • The volumetric evolution of the oscillatory expansion of the melt pool, different from that in the planar, V-shaped trough, was revealed. • The heat transfer characteristics of the melt pool with different angles of the V-groove were revealed with Marangoni convection patterns at different viewing angles. • The mechanism of cavitation generation in V-grooves with small pinch angles and its avoidance measures were predicted. In comparison to planar-oriented laser cladding, non-planar laser cladding also deserves to be discussed. A numerical model of non-planar laser cladding was constructed for V-grooves with different tension angles. The simulation results show that the melt pool generated at the bottom of the V-groove undergoes an oscillatory expansion phase similar to that of planar laser cladding and ends up in a periodic steady state. As the tension angle θ of the V-groove decreases, the absorption of laser energy by the bevels on both sides becomes more and more, and the melt pool volume starts to decrease. However, after θ is reduced to a certain threshold, the melt pool volume starts to become larger instead, and this change brings about a complex melt pool convection pattern. Finally, the mechanism of cavitation generation at the bottom of the V-groove when θ is less than 60° and the possible avoidance measures are also analyzed. [ABSTRACT FROM AUTHOR]

Due to the complex transient characteristics, it is difficult to directly measure the formation and development of a molten pool formed by laser cladding. Considering the change of thermophysical properties at high temperatures and the coupling between the heat source and the molten pool surface, a new numerical simulation method was proposed and verified. The thermal history and formation of the molten pool, the convective pattern, and the solidification morphology of the cladding have been analyzed. The results show that the molten pool can reach steady-state in a very short time, and both considerable temperature gradient and fast circular convection exist in the molten pool. The bottom of the molten pool mainly showed columnar growth, while the top was equiaxed. Columnar to equiaxed transition occurred at the center of the molten pool. • Established a multiphysics three-dimensional simulation model for laser cladding. • Two annular Marangoni convections were founded inside the molten pool. • Evaporation hardly affects the shape of the cladding. • CET occurs during solidification. [ABSTRACT FROM AUTHOR]