Electron beam welding, laser beam welding and gas tungsten arc welding of titanium sheet

Microstructures, properties and technical parameters of welding specimen of 0.5 mm thick sheets of commercial purity titanium (C.P. Ti) have been studied via high vacuum electron beam welding (EBW-HV), CO2 laser beam welding (LBW) and gas tungsten arc welding (TIG), as well as optical microscope (OM) observation and microhardness measuring. The results indicate that the EBW is more suitable for C.P. Ti sheets welding, and the welding seam without defects can be obtained. The tensile strength and microhardness of joints are corresponding to matrix structure. The full-penetration butt welds are obtained by TIG, but they have many defects such as wide weld-seam, big deformation and coarse grains. The LBW has many advantages such as the narrowest weld-seam, the least deformation and the finest grains. The fine grains are good for properties of weld seam, but the LBW should be studied again for the reasons of unstable welding technologies and strict condition.