Effect of Directional Lorentz Force on Molten Pool Exhaust in Laser Cladding

The stationary magnetic and electric fields are coupled to form the directional Lorentz force. Based on the multi -physics field coupling theory and the mesh deformation method, the molten pool model under the effect of the directional Lorentz force is built, and the bubble movement process in molten pool is simulated by the discrete element method. The comparison of numerical results with and without directional Lorentz force but both under the same laser cladding process conditions indicates that the directional Lorentz force possesses an excellent ability to regulate pores. When the direction of the Lorentz force is upward, the maximum velocity of molten pool is suppressed by 62. 5, the gas bubble movement direction deflects downward, and the pores in cladding layers increase obviously. When the direction of the Lorentz force is downward, the maximum speed of molten pool is suppressed by 25%. Nevertheless, for the reason of the increase of the bubble buoyancy, the bubble is accelerated and escapes from the melting pool, and a dense cladding layer without any pores is obtained. The simulation results agree well with the experimental ones, which confirms the reliability of this simulation model.