Simulation and experimental verification of thermal cycling characteristics of IN718 superalloy multi-pass cladding
In order to reveal the heat accumulation characteristics and rules of laser cladding process,ANSYS software was used to simulate the thermal cycling during the preparation process of IN718 superalloy multi-pass cladding coating.By constructing a"T"type Gaussian composite heat source and developing an ANSYS APDL program to reproduce the laser cladding process,the temperature distribution and thermal cycling characteristics of the coating were obtained.The results show that the high-temperature area of the cladding coating rapidly diffuses in a semi-ellipsoidal shape,following a"bow"shaped path to generate heat accumulation.In the scanning direction,the maximum temperature of each node(2309.26 ℃ → 2417.15 ℃ → 2454.58 ℃)shows a nonlinear and slow increasing trend.Using a"bow"shaped path for cladding will significantly store energy at overlapping bends,causing repeated heating or remelting of the melted coating.At the bonding interface,there is symmetry between the heat generation and heat conduction of the coating heat source during the intermediate pass cladding,resulting in the interface temperature being higher than the melting point of the metal powder material.The infrared thermal imaging temperature measurement method is used to monitor the cladding process,and the monitoring results are basically consistent with the simulation results,providing a theoretical basis for optimizing the cladding process and regulating the microstructure of the coating.
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