Detailed Analysis of a Spiral Scanning Trajectory for Slender Axis Laser Cladding
L-J. Cui, C-J. Hao, S-R. Guo, H. Du, H-Y. Li, Y-L. Cao, G. Cheng and W-H. Zeng
The scanning trajectory method of laser cladding has a great influence on the quality of the clad layer. Herein, the effects of single spiral and double spiral trajectories on the clad morphology, temperature gradient and solidification rate of the Fe-based powder clad at different solidification positions during the injection of the cladding powder on a 45 steel elongated slender shaft when cladding with a high power diode laser (HPDL) are investigated. A three-dimensional (3-D) mathematical model was developed. The temperature variation curves of the substrate and the molten coating were obtained by the birth-death cell technique. The influence of the output parameters on the coating quality was analysed and discussed. In order to verify the reliability of the model, experimental tests were carried out to verify the surface quality and tissue morphology of the molten coating under the two scanning methods. The results show that the agreement between the theoretical calculation results and the experimental results is good. In addition, both scanning methods generate pores at the coating laps. The above conclusions are further confirmed by the dimensional change analysis. For this reason, this paper serves as a good guideline for the melting and cladding process of slender shafts.
Keywords: High power diode laser (HPDL), 45 steel, Fe-based powder, laser cladding, spiral trajectory, long and thin axis, mathematical model, temperature field, simulation, bubble