不同退火温度对镍基合金焊接接头的疲劳性能影响OA

The residual tensile stress generated during the welding process can significantly reduce the fatigue life of the joint.As the annealing temperature increases,the residual stress gradually relaxes,dislocation recombination and grain boundary slip intensify,and the residual stress decreases significantly,thereby reducing the tendency for fatigue crack initiation.However,excessively high annealing temperatures can lead to abnormal grain growth,which in turn reduces fatigue strength.Therefore,the influence of different annealing temperatures on the fatigue performance of nickel based alloy welded joints is studied.For N06200 nickel based alloy sheet with a thickness of 6mm,three gradient annealing temperatures of 650℃(low temperature),800℃(medium temperature),and 950℃(high temperature)were set to prepare welded joint specimens,and the basic and fatigue properties of the specimens at different annealing temperatures were tested.The experimental results show that at the basic performance level,the microhardness of the N06200-650 sample annealed at low temperature is lower,while the N06200-800 sample annealed at medium temperature and the N06200-950 sample annealed at high temperature both achieve higher hardness.Fatigue testing found that the fatigue life of samples annealed at 950 ℃ was significantly longer than the other two groups.In terms of fatigue crack propagation characteristics,the N06200-950 specimen has the slowest crack propagation rate,only increasing from 5 × 10-6mm/cycle to 1 × 10-4mm/cycle.Therefore,950℃ can be selected as the annealing temperature for nickel based alloy welding joints.