Effect of laser ablation of substrate on the morphology of the laser cladding layer

Abstract

How to accurately and effectively modulate the morphology of the laser cladding layer is very important in the field of laser surface strengthening. In this paper, the surface morphology and roughness of the cladding substrate are accurately controlled by the nanosecond laser ablation process, and its influence on the morphology of the cladding layer is analyzed. Before laser cladding, a nanosecond laser was used to perform ablation pretreatment on the surface of 45 steel substrate. The analysis results show that when the laser power exceeds the ablation threshold, the substrate surface forms a microsphere structure caused by the melting–solidification process. At the same time, a linear relation between the substrate surface roughness and the laser power was obtained. Subsequently, a laser cladding experiment was performed on the roughened substrate surface, and the morphology of the cladding layer was analyzed. The results show that after the substrate is ablated by a nanosecond laser, the cladding angle, dilution rate, and cladding depth of the cladding layer decrease with the increase of the substrate surface roughness, and the clad width and clad height increase with the increase of the surface roughness. The results show that the surface roughness of the substrate can be accurately controlled by the laser ablation method, which can help to optimize the macroscopic morphology of the laser cladding layer and obtain a cladding coating with better performance.