Study of the melt pool shape under laser treatment of AISI 316L steel taking into account Marangoni convection effect

The paper considers the two-phase physical and mathematical model of the AISI 316L stainless steel melting and its numerical implementation by the finite volume method in the ANSYS CFX software based on the well-known concepts of simulating the thermocapillary convection. Approximation functions are proposed to take into account the effective specific heat and dynamic viscosity in the transition process from a solid to the liquid state to minimize the numerical error in the vicinity of the liquidus and solidus temperature points. The molten pool formation process was considered under the action of laser radiation with the Gaussian intensity profile taking into account boundary conditions of the Marangoni convection, convective heat transfer and radiative heat transfer. Influence of the thermocapillary convection on the shape of the molten pool wetted surface is shown. An approach is proposed to control flows on the free surface of the molten pool by changing the laser intensity profile.