Thermal fatigue mechanisms in laser cladding at varying elevation angles for metallurgical bearing seats

Laser cladding is critical in repairing and remanufacturing high-value parts, especially for complex curved parts. However, the curved surface shape may cause the uneven distribution of laser energy, and the laser head needs to be adjusted to obtain the appropriate elevation angle to meet the requirements of different working conditions. The elevation angle will change the laser irradiation angle and the thermal influence depth, which will affect the surface thermal fatigue damage. It is significant to quantitatively reveal the multi-field coupling behavior and thermal fatigue damage mechanism during laser cladding for curved parts to improve the cladding quality and performance. In this paper, a numerical model of multi-field coupling and thermal fatigue during laser cladding under different elevation angles on the inner hole of metallurgical bearing seat was established. The instantaneous evolution of multi-field coupling and fatigue damage mechanism were revealed by solving the model, and the interactive effects of temperature, flow velocity, stress and thermal fatigue during laser cladding of curved surface substrate were quantitatively analyzed. The calculated results were compared with the flat surface substrate cladding. The results indicate that the values of the cladding temperature, the flow velocity, and the minimum fatigue life are relatively smaller under the same circumstances. Finally, the experimental and numerical simulation results are compared to verify the model effectiveness.