Numerical Analysis Of Microstructure Evolution Process Of Inconel718 On Q345 Surface By Arc Cladding

As a common superalloy,Inconel718 nickel-based superalloy is often used in aviation,aerospace and other fields due to its high temperature resistance,corrosion resistance and oxidation resistance.As a typical low alloy steel,Q345 has good comprehensive mechanical properties,but its corrosion resistance is poor.Therefore,it is of great practical significance to use the arc cladding technology with simple equipment,low cost and small deformation to modify the surface of Q345 to obtain high value-added parts.However,there are great limitations in studying the temperature field and microstructure evolution of the cladding layer by traditional experimental methods.At present,with the development of computer technology and the improvement of solidification theory knowledge,the numerical simulation method can be used to observe the temperature change law and microstructure evolution of the arc cladding layer in real time,and provide guidance for the optimization of the actrual cladding process parameters.The purpose of this paper is to simulate the evolution of temperature field and microstructure of Inconel718 alloy during arc cladding on Q345 surface.Firstly,based on the heat transfer theory,combined with the finite element knowledge,the three-dimensional temperature field evolution model is established by using ANSYS programming language and life and death element technology,and the dynamic evolution process of temperature field of single-channel cladding layer is studied.Based on the temperature field model of single-channel cladding layer,the variation law of molten pool morphology of cladding layer under different cladding current and cladding speed was analyzed.Furthermore,based on the single-channel cladding layer model,the temperature field model of the multi-channel cladding layer is established to study the dynamic evolution process of the temperature field of the multi-channel cladding layer.The research shows that the former cladding has a preheating effect on the latter cladding,and under the effect of heat accumulation,the cooling time required for the workpiece is longer.The thermal cycle curves of feature points at different positions of single-channel and multi-channel cladding layers are extracted to further study the variation law of temperature field.Finally,the simulation results are compared with the experimental results.The results show that the model has good accuracy.Based on the theory of grain nucleation and growth and multi-alloy treatment,a cellular automaton model of quaternary alloy solidification suitable for the microstructure evolution of two-dimensional cladding layer was established.The accuracy of the model was verified by the equiaxed crystal growth process under uniform temperature field and the columnar crystal growth process under non-uniform temperature field.The distribution of different solute elements in solid and liquid phases was simulated,and the segregation of solute elements was discussed.Furthermore,the interpolation algorithm is used to combine the Gaussian heat source model with the cellular automata model to construct a cellular automata-finite difference model(CA-FD)suitable for simulating the microstructure evolution of the cladding layer,which is used to simulate the grain growth process of the cladding layer.At the same time,the grain growth law under different process parameters is also studied.Finally,combining the above cellular automata model with the phase analysis software,a phase transition model suitable for the solidification process of Inconel718 alloy was established to simulate the phase transition process of the cladding layer.Finally,the simulation results are compared with the experimental results from the bottom morphology,phase composition and solute element distribution of the cladding layer.The results show that the model has good accuracy.In summary,in this paper,the evolution of temperature field and molten pool field of Inconel718 alloy during arc cladding process is studied by computer simulation.The evolution mechanism of temperature field and molten pool field during arc cladding process is expounded.The influence of different process parameters on the microstructure evolution of cladding layer is explored,which has certain reference significance for the study of subsequent alloy solidification process.