Quantitative analysis and experimental study of the influence of process parameters on the evolution of laser cladding

Abstract

To avoid and eliminate cracks on the surface of a workpiece, it is very important to quantitatively analyse the temperature field, stress field, and flow field during the laser cladding process. This paper uses the finite element method to establish a multiphysics coupling model based on the laser cladding process of a disc laser. The thermophysical parameters of the base material ASTM 1045 and the powder material Fe60 are calculated by the CALPHAD method. In the modelling, the mutual influence between the light powder is considered but also the influence of the surface tension and buoyancy of the liquid metal in the molten pool on the flow of the molten pool and the dynamic change of the cladding layer morphology are considered. In the laser cladding process, the distribution and change law of the temperature field, flow field, and stress field are obtained. An infrared thermometer was used to measure the temperature during the cladding process, and a Zeiss-ƩIGMA HD scanning electron microscope was used to observe the outline of the cladding layer, which verified the accuracy of the mathematical model. The response surface model was established by the CCD method, and the influence law of the process parameters on the cladding layer was determined. The influence of laser power, beam radius, and scanning speed process parameters on the changes of temperature field, flow field, and stress field in the cladding process was analysed, providing an effective way to reduce residual stress.