2018 年 56 巻 6 号 p. 239-245
This report described the experimental results and discussions on the effects of laser brazing conditions and brazing materials on the properties of dissimilar-metal butt joint of austenitic stainless steel (SUS304) to commercially pure titanium (TP340) in 2 mm thickness. Brazing material of 1 mm in thickness was fixed between SUS304 and TP340, and YAG laser with 0.3 mm in focal spot diameter was irradiated for brazing. Within the particular range of brazing conditions where no crack occurred with a Cu-10Ni brazing material, the butt joint tensile strength increased with a decrease in laser power and a rise in brazing speed, and an increase in the shift of laser irradiation position into SUS304 side. The tensile strength was affected by the heat input, and it could be organized as a function of the thickness of intermetallic compound layer composed of Ti2Cu, TiCu and Ti2Cu3 formed along the fusion boundary of Ti base metal. As a result of the examination of brazing materials, the joint tensile strength was affected by the brazing material variation, mainly due to brazed metal hardness and thickness of compound layer at fusion boundary of Ti base metal.