Simulation Analysis Of Residual Stress In Plasma Sprayed Thermal Spraying Layer

With the rapid development of the industry,it is a common method to make important parts more reliable through surface engineering.As a common method of coating preparation,plasma spraying is widely used in surface strengthening of parts.Residual stress is one of the important reasons for coating failure.Therefore,it is important to study the state of residual stress in the coating and the stress change under working conditions.The coating deposition process plays a decisive role in the formation of residual stress,but the real-time monitoring of the process is currently impossible,so numerical simulation has become an important method to study the coating deposition process.In this paper,the finite element model of the deposition process of NiCrFeMo coating on GH4169 substrate is established by using finite element analysis software.The temperature field and stress field of the deposition process are analyzed.As the influencing factors,the spraying power,scanning speed and coating thickness are selected.The effects of various factors on the temperature field and stress field of the coating deposition process are analyzed.The changes of the stress of the coating after the preparation are studied under thermal cycling,and the effect of creep on the stress in the coating is analyzed.Through the simulation of the coating deposition process,there is a temperature gradient in all directions of the coating during the spraying process.The temperature of the joint in the coating fluctuates periodically with time,and there is a large temperature difference between the substrate and the coating;During the spraying process,it fluctuates periodically;after cooling to room temperature,the stress distribution of the coating is relatively uniform,but the stress concentration at the edge and the bonding interface is obvious.The study on the factors affecting the coating stress found that the coating stress increased with the increase of the spraying power and coating thickness,and decreased with the increase of the scanning speed.The stress change of the coating under thermal cycling shows that the stress changes in the heating phase and the cooling phase are obvious,and the stress changes in the constant temperature phase are not large;the creep will cause the stress distribution of the coating to be uniform under the thermal cycle and the stress value to decrease.