Effects of welding parameters on weld shape and residual stresses in electron beam welded Ti2AlNb alloy joints
(1. Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China;
2. Beijing Institute of Radio Measurement, Beijing 100854, China;
3. State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China;
4. Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Tsinghua University, Beijing 100084, China;
5. Capital Aerospace Machinery Company, Beijing 100076, China;
6. China Academy of Launch Vehicle Technology, Beijing 100076, China)
2. Beijing Institute of Radio Measurement, Beijing 100854, China;
3. State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China;
4. Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Tsinghua University, Beijing 100084, China;
5. Capital Aerospace Machinery Company, Beijing 100076, China;
6. China Academy of Launch Vehicle Technology, Beijing 100076, China)
Abstract: In order to estimate the residual stresses in Ti2AlNb alloy jointed by electron beam welding (EBW), a computational approach based on finite element method was developed. Meanwhile, experiments were carried out to verify the numerical results. The comparison between the simulation results and measurements suggests that the developed computational approach has sufficient accuracy to predict the welding residual stress distributions. The results show that the central area of the fusion zone suffers tensile stresses in three directions. When the other parameters remain unchanged, the focus current has great impact on the weld shape and size, and then affects the residual stress level significantly. Moreover, the thick plate full-penetrated EBW weld suffers near 1000 MPa tensile stress of Z-direction in the center of the fusion zone. The wider weld has lower tensile stress in Z-direction, resulting in lower risk for cracking.
Key words: Ti2AlNb alloy; residual stress; numerical simulation; electron beam welding