| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a laser beam welding method which is used for a high-tensile steel plate with Ceq exceeding 0.35 and which can prevent a weld metal from being hardened and form a weld part of excellent formability. <P>SOLUTION: In the laser beam welding method of a high-tensile steel plate with Ceq exceeding 0.35, a heating means is provided which locally heats a portion including a weld metal in a period of≥0.1 second and≤10 minutes to a temperature immediately below the Ac<SB>1</SB>transformation point and≥400°C after at least one second is elapsed after the welding laser beams have passed. Laser beams 3 of a power density of≥0.005 MW/cm<SP>2</SP>and≤0.5 MW/cm<SP>2</SP>are used for the heating means. Heating by arc plasma, conductive heating by seam welding, or induction heating by a high frequency wave is used for the heating means. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
