Dissimilar metal welding titanium and steel sheet by fiber laser

Abstract

Recently, the development of laser welding technology with dissimilar metal is demanded in the automobile, aerospace, and sea-water plant industry. Titanium alloy has been increasing to use for important mechanical parts. In this study, the lap joint welding was performed with dissimilar metal sheets such as titanium and steel by CW fiber laser. The welding strength of dissimilar metal was estimated by tensile shear test. The characteristics of bead were investigated under various experimental conditions. Especially, the effect of welding speed on the formation of inter-metallic compound was examined to get higher tensile strength of joint. A sound bead formation with high velocity was discussed to find out the relationship between diameter of focused beam size and welding speed. The diameter of focused beam was closely related with the actual Key-hole diameter. That is, as the diameter of key hole was smaller the possibility of the high speed welding was better.Recently, the development of laser welding technology with dissimilar metal is demanded in the automobile, aerospace, and sea-water plant industry. Titanium alloy has been increasing to use for important mechanical parts. In this study, the lap joint welding was performed with dissimilar metal sheets such as titanium and steel by CW fiber laser. The welding strength of dissimilar metal was estimated by tensile shear test. The characteristics of bead were investigated under various experimental conditions. Especially, the effect of welding speed on the formation of inter-metallic compound was examined to get higher tensile strength of joint. A sound bead formation with high velocity was discussed to find out the relationship between diameter of focused beam size and welding speed. The diameter of focused beam was closely related with the actual Key-hole diameter. That is, as the diameter of key hole was smaller the possibility of the high speed welding was better.