Procedure Qualification of TC4ELI Titanium Alloy with Horizontal Electron Beam Welding for Submersible Hull

摘要

The horizontal electron beam welding (EBW) was used on TC4ELI alloy with 60 mm thickness, and the welding procedures and the properties of the joints involved in the manufacturing of the submersible hull were investigated. The weld had alpha' martensite microstructure, which was uniform along the welding penetration, and the micro-hardness of the weld was 322-356 HV0.2. The tensile strength of the joint was 915 MPa, equivalent to that of the base metals, and the percentage elongation after fracture was more than 12%. The impact absorption energies of both the weld and heat-affected zone specimens were above 30 J, and the bending angle of the joint reached 180 degrees. The effects of the microstructure and macromorphology on the mechanical properties of the joints are discussed. The properties proved the reliability of EBW for the manned submersible hull, which would contribute to developing the manned submersibles.