Abstract
The paper analyses joining of titanium Grade 2 and Grade 5 sheets using electron beam welding, EBW, technology. The joined sheets undergo further processing to produce final aircraft component. EBW is a fusion welding process that utilizes electrons to produces heat and join materials. It is characterized by low heat input, small distortions, precise and repeatable welding parameters and vacuum operating conditions. Titanium is a unique material that offers high specific strength, heat resistance and corrosion resistance. In aerospace applications it is used for components of rotors, engines and airframes. Tailor Welding Blanks is a technology of joining sheets of different properties in order to obtain components that have mixed properties. Titanium Grade 2 has better formability while titanium Grade 5 has higher strength. The welded sheets are further formed in order to obtain final shape. The numerical simulation of the welding process investigates the impact of thermal load produced by a moving electron beam on the deformations occurring in the joined sheets. The model is based on finite element method and it takes into account elastic, plastic and thermal strains. The analyzed sheets have thickness of 0.8 mm, their small cross-section contributes to significant post-welding bending both in transverse and longitudinal directions. The paper analyzes the influence of mesh structure and welding gap on the degree of deformation. The obtained numerical results were compared with actual welding deformations. The research into modeling of titanium sheets welding was extended with analysis of joint behavior during tensile tests. Specimen was cut out from the joint and was subject to uniaxial tensile test. The strains occurring during tension were recorded using optical non contact measurement system that uses two cameras. The experimentally measured strains were compared with numerical results from a separate finite element method model.