Experimental Analysis and Simulation of Ultrasonically-assisted Laser Cladding TiCN Ni-based Reinforced Coatings
C.Y. Li, J.H. Li, F.P. Yao, D.Q. Zhang and X. Chen
A TiCN Ni-based reinforced coating was prepared in situ on H13 steel by ultrasonically-assisted laser cladding, and the effects of temperature field and residual stress in the clad layer were investigated by changing the ultrasonic frequency. The analysis model is established by COMSOL simulation software and verified experimentally. The results show that the application of ultrasound can effectively reduce the temperature change of the temperature field, make the temperature field distribution more uniform and the range of temperature gradients of zero becomes larger. The maximum temperature in the clad layer shows a wave shape with an upward trend and the higher the frequency, the more obvious the upward trend. The average maximum temperature of the clad layer rises and the temperature difference shows a trend of first decreasing and then increasing. An the ultrasonic frequency causes the temperature of the vertical direction of the clad layer shows an upward trend with the maximum temperature difference in the vertical direction shows a tendency to increase first and then decrease, and the maximum temperature difference of 170 K is reached at 0.7 mm from the top of the clad layer, and then the temperature difference gradually decreases and tends to stabilize at about 90 K. Along the direction of laser scanning the residual stress shows a trend of first decreasing and then increasing and then decreasing, and with the increase of ultrasonic frequency, the overall residual stress shows a decreasing trend. Ultrasonic cavitation effects, mechanical effects and sound flow effects significantly refine the microstructure of the cladding layer, increase the nucleus rate, and inhibit grain growth.
Keywords: Fibre laser, H13 steel, TiCN Ni-based reinforced coating, laser cladding, ultrasonic frequency, temperature gradient, residual stress, grain refinement, finite element (FE), COMSOL