Patent ID: 8114528

Claim:
An electron beam welded joint excellent in brittle fracture resistance in a butt welded joint of a welded structure characterized in that a hardness of a weld metal is over 110% to 220% of a hardness of a base material and in that a width of the weld metal is 20% or less of a plate thickness of the base material, wherein said electron beam welded joint is characterized by containing, as a base material, by mass %, C: 0.02 to 0.2%, Mn: 0.8 to 3.5%, S: 0.0005 to 0.0025%, Al: less than 0.02%, and Ti: 0.01 to 0.05%, using a steel material having a value of Pcm expressed by the following formula (a) of 0.12% to 0.5% material, having an amount of O contained in the weld metal of the welded joint of 20 ppm or more, and similarly having an amount of oxides of a grain size of 2.0 μm or more of 10/mm 2 or less: Pcm=C+Si/30+Mn/20+Cu/20+Ni/60+Cr/20+Mo/15+V/10+5B (a).