| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a laser joining method where different kinds of metals having different laser reflectivities and thermal conductivities can be efficiently lap-welded in high quality. <P>SOLUTION: In the laser joining method where a lower plate 10 made of an iron based material and an upper plate 11 made of a copper based material having a laser reflectivity and a thermal conductivity higher than those of the iron based material are lapped, and a laser L is emitted from the side of the upper plate 11, so as to lap-weld both the plates, a recessed hole 12 is beforehand formed in the upper plate 11, the laser L is emitted in such a manner that an emission pattern is formed at the bottom of the recessed hole 12, and the thin part 12a at the bottom of the recessed hole 12 is concentrically heated and melted. Since the thin part 12 is heated and melted, the upper plate 11 can be efficiently heated and melted even without so increasing the energy density of the laser, thus the phenomenon of energy over on the side of the lower plate 10 is eliminated, pitting in the lower plate 10 is prevented, and further, the gasification of low boiling point components causing the generation of blow holes is suppressed as well. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
