Effects of Welded Pores on Fatigue Life of Titanium Alloy Electron-Beam Welded Joints

The welded pore is one of common defects in titanium alloy electron-beam welded (EBW) joints and significantly influences its fatigue life. In this paper, effect of the welded pore on fatigue life of titanium alloy EBW joints were studied through an experimental investigation. Fatigue tests and fracture observation were conducted for EBW joints. Results showed that the welded pore is the most possible crack initiation. Through quantitative analysis on pore size and depth, a model was established to characterize the effect of initiation pore on fatigue life based on S-N model. Moreover, the effect of pore scatter on fatigue life scatter was investigated based on Monte-Carlo simulations, and the results indicated that scatter of pore size and depth is the key factor contributing to the wide scatter of fatigue life of welded joints.