Research On Solid Forming Process Of Three-beam Inside-Laser Wire Feeding Cladding

In the laser cladding process,compared with powder feed cladding,wire feeding cladding has the advantages of high material utilization rate,low cost,little impact by space environment and almost no pollution.In this paper,based on the self-developed new three-beam inside-laser wire feeding nozzle made by the laboratory,the solid forming process of internal wire feeding was studied.In this paper,the coupling characteristics of the three-beam inside-laser wire feeding nozzle developed in the laboratory were studied.The transition forms of the wire into the fusion pool process with different coupling characteristics in the cladding were obtained.The heat source model of the three-beam light source was established,and the temperature field of the molten pool was simulated and analyzed with ANSYS so ftware.Based on the temperature field simulation,single factor experiment and orthogonal experiment,the influences of basic process parameters on the morphology and dilution area of the cladding layer were studied.The influences of defocusing amount,laser power,scanning speed,scanning direction and wire feeding speed on the width,height and dilution area morphology of the cladding layer were obtained respectively.The results show that the process parameters all affect the width and height of the cladding layer,among which the defocusing amount and scanning direction have great influence on the dilution area of the cladding layer.When the defocusing amount increases,the dilution area of cladding layer will gradually change from V shape to W shape.When the scanning direction changes,the maximum penetration depth in the dilution area of cladding layer will change.The effect of lap rate on the size and surface flatness of cladding layer was studied.The temperature field of single-layer multi-channel lap up and multi-layer multi-channel stacking cladding layer is simulated by ANSYS software.The changing rules of temperature,temperature gradient and temperature change rate were analyzed and summarized.The temperature gradient in the z direction of the cladding layer is the largest,so cracks are more likely to appear in the z direction.The temperature change rate of the first cladding is higher than that of the subsequent cladding.In this paper,the scanning path was planned for the multi-channel and multi-layer stacking.The scanning path was selected according to the characteristics of the three-beam inside-laser,and the optimized parameters were used to carry out the solid forming experiment.The surface flatness,microstructure,microhardness and tensile strength of the formed entity were analyzed.Results show that along the long side and along the short side scan entity surface roughness is relatively close.Inner cladding layer hardness is fluctuated,but the overall distribution is relatively uniform.The tensile strength,yield strength and elongation of the formed part are higher than that of the transverse part,showing a certain anisotropy.The fracture mode of tensile part is ductile fracture.According to the model and the optimized process,the morphology characteristics of the cladding layer of three-beam inside-laser wire feeding cladding can be predicted,and the process can be stabilized.It provides technical support for the new three-beam cladding process and the application of the nozzle.