The Influence And Mechanism Of Residual Stress Of High-temperature Welding For 16mnr Welding

The welding residual stress can not be avoided in the welding technology, its harm is tremendous. During the welding process the highly concentrated heat input cause uneven heating of local materials, uneven temperature field will be generated in the component materials and it will cause uneven expand and uneven elastic deformation, which cause high welding residual stress. While welding residual stress has great influence on the fatigue, brittle fracture, stress corrosion damage, and dimensional stability, which is the root cause of equipment damage. Therefore, reduce or eliminate the welding residual stress has great practical significance to the greatest extent.High-temperature welding processes are a new method of welding technology. It heats the component to a certain temperature; ensure the same temperature in the component. Then in the case of keeping the temperature maintain the zero or minimum temperature. So it is a method that can reduce the welding residual stress. The guiding ideology of high-temperature welding processes is to improve performance by reducing the welding residual stress.This issue makes 16MnR as the experimental materials, use high-temperature welding processes to weld in the room temperature, 750℃and 850℃. Through the measuring of the welding residual stress, corrosion test, fatigue test, metallographic analysis of experiment and data, comparative analysis the change of value of residual stress, corrosion resistance, fatigue resistance, it indicates that high-temperature welding processes can reduce the residual stress, corrosion resistance and fatigue resistance have significantly improved. In this experimental condition, the maximum of residual stress after 750℃high temperature welding specimen than room temperature, the rate of reducing:longitudinalηx is 55%, horizontalηy is 56%.The value of residual stress after 850℃high temperature welding specimen than room temperature, the rate of reducing:longitudinalηx is 68%, horizontalηy is 68%. This experiment 16MnR steel is put in the acid corrosion environment, The year rate of corrosion is lowered 37.93% under 750℃heat treatment after welding the specimens welded specimens than room temperature, the year rate of corrosion is lowered 50.05% under 850℃heat treatment after welding the specimens welded specimens than room temperature.In the alkaline corrosion environment, The year rate of corrosion is lowered 35.24% under 750℃heat treatment after welding the specimens welded specimens than room temperature. The year rate of corrosion is lowered 44.85% under 850℃heat treatment after welding the specimens welded specimens than room temperature. In the salt corrosion environment, The year rate of corrosion is lowered 47.91% under 750℃heat treatment after welding the specimens welded specimens than room temperature. The year rate of corrosion is lowered 54.47% under 850℃heat treatment after welding the specimens welded specimens than room temperature. In this experiment,16MnR steel is welding processed in the high temperature of 750℃, the number of fatigue cycles is increased 30.7% than room temperature. The number of fatigue cycles is increased 51.8% under 850℃heat treatment after welding the specimens welded specimens than room temperature.This issue has made a mechanism for why can reduce the welding residual stress,improve the tensile stress corrosion, fatigue resistance.