Numerical simulation and experimental study of temperature and stress fields during laser cladding of multi-layer Ni60A alloy

Abstract

In this paper, a three-dimensional model with thermal and mechanical coupling is established by the finite element method, and the reliability of the model is verified by the experiment. Based on this model, the influence and mechanisms of the process characteristic of multi-layer stacking, laser power, and scanning speed on the temperature and stress fields at different positions within the cladding layer during laser cladding forming of multi-layer thin-walled parts are analyzed. The layer number affects the temperature fields at different locations mainly through heat accumulation and the movement of the heat source in the vertical direction. Moreover, the stress along the scanning direction within different positions of the cladding layer is maximized during the forming process of each layer. The layer number has little effect on the evolution process of the stress direction during the spot movement. However, the transient stress at different positions at the end moment of the current layer forming is all affected by the layer number. In addition, the relationships between this transient stress and the laser power and scanning speed are affected by the residual heat due to the thermal accumulation during the multi-layer stacking process. Finally, based on the simulation results, the change rules of microstructure morphology in the multi-layer thin-walled part are discussed. The work in this paper aims to provide a basis for high-quality laser cladding of multi-layer thin-walled parts oriented to the Ni60A alloy.