The Fatigue Property And Residual Stress Effect Of The Tc4 Titanium Alloy Electron Beam Welded Joint

Titanium alloy with many advantages, for example high strength, good corrosion resistance and good heat-resistance, is widely used in aviation, space navigation, shipbuilding, chemical machinery manufacture and medical appliance. Electron beam welding is one of the best methods employed in the welding of titanium alloy because of high energy density, small heat-affected zone, and low pollution etc. There are four representative shape welded seams with different electron beam welding technology. It is significant to research the fatigue property of welded joints with different shape welded seam. Meanwhile, electron beam welding generate high residual stress. The existence of residual stress is the important element for structural strength and service performance. It is very important meaning for engineering practice to find out the effect of residual stress on welded joint fatigue life.Simulate fatigue life of welded joints with different shape welded seam in Patran, Nastran, Marc and Fatigue, which are the MSC company products. In the case of not considering residual stress, figure out welded joint stress distribution and fatigue life in tension and find out the key factor of effecting welding property. In the case of considering residual stress, figure out welded joint stress distribution and fatigue life in tension and compare with no residual stress case. The outcome is that sudden geometry change and defect of welded seam will generate concentrated stress in tension to reduce the fatigue life. The fatigue break happen at weld toe and heat affected zone. Residual stress almost not effect welded joint stress distribution and fatigue life.