The Mechanism Of Ni-based Alloy Laser Cladding And Experiment Research

Laser cladding technique uses high energy density laser beam to make cladding material and a portion of base material rapidly melt and solidified,forming a composite coating with excellent properties.The technology,which is an extremely promising high-tech,can effectively improve the surface quality of the material.By selecting cladding material match to the base material can maximize the potential of the cladding material,which can not only improve the performance of the workpiece,shorten manufacturing cycle,but also get significant economic benefits.Thus it has a wide range of applications in the aerospace,medical science,automobile,mold and other fields.Single-channel pre-prepared powder cladding is chose as the research object in this paper.The contents of research are as follows:(1)The theoretical research on laser cladding technology is done.The effect of laser power,scanning speed,the amount of defocus,the dilution rate and the overlapping on cladding layer quality are studied.Meanwhile the interaction of the laser,powder and the substrate material are summarized,and the reasons for the cladding layer surface quality and generation of defects are briefly analyzed.(2)The article uses the ANSYS finite element analysis software is used to simulate the complete distribution of laser cladding temperature field in the process,and analyses the different nodes of positions the temperature distribution and temperature field distribution in the pool depth and radial directions,which agree well with the actual experimental results,and give some guidance for the following experiment and the practical application of laser cladding forming technology.(3)Nd:YAG laser is chose as a heat source,45#steel as the base material,cladding Ni60 alloy powder on its surface.In order to research macroscopic morphology of the different parameters of the cladding layer,the cross-sectional dimensions of the cladding layer,microstructure,and microhardness,I adopt single factor variable experiment to determine reasonable laser parameters,and summary the effect of experimental parameters on experimental results.(4)The optimal parameters are obtained from experiments by controlling variables:defocusing amount 13mm,current 260A,scanning speed 2.5mm/s,powder preset thickness 0.5mm,pulse width 3.0ms,frequency rate 15Hz,Which can guarantee that cladding material be formed metallurgical bonding with the substrate,and the substrate surface obtain a relatively small dense uniform,good quality cladding.There are little cracks and holes or other defects,proposing measures to resolve them.