Investigation on the Interaction Law between Laser and Powder and Multi-Field Coupling Mechanism during Laser Cladding under Different Elevation Angles

During laser cladding under different elevation angles, there is an interaction between the waist beam and the laser energy. The interaction law is complicated, involving many physical and chemical processes such as laser energy absorption, powder melting, evaporation and solidification. It is a bottleneck problem in the industry to quantitatively reveal the interaction law between laser and powder during cladding, which is significant to improve the cladding quality. In this paper, a continuous-discrete phase gas/solid coupling model of laser and powder interaction during laser cladding under different elevation angles was established. In the modeling, the random distribution of 316L powder with different particle sizes was realized through Rosin-Rammler-Sperling curve fitting, and a custom UDF cone heat source program was written to calculate and reveal the temperature, concentration and flow velocity of powder with random particle size distribution during cladding under different elevation angles. The effects of different elevation angles of laser head on powder convergence and laser powder interaction were quantified. On this basis, the multi-field coupling numerical model of laser cladding process under different elevation angles was established, and its transient evolution was revealed. The calculation shows that the powder temperature, concentration, flow velocity and cladding layer height of 15° elevation angle are more in line with the process requirements, and the convergence of powder reaching the substrate is better. Finally, the temperature of the cladding process was collected by infrared thermal imaging camera, and the cladding profile was compared and analyzed to verify the effectiveness of the model.