| United States Patent | 6,441,335 |
| Nagaoka | August 27, 2002 |
In welding joint surfaces of a high-hardness member and a low-hardness member to each other by use of a laser beam or an electron beam, the point of irradiation of the laser beam or electron beam is offset from the joint surfaces of the high-hardness member and the low-hardness member toward the low-hardness member by a predetermined distance, such that the melting provided by the beam is caused to spread from the low-hardness member to the high-hardness member. Thus, even if the two members different in hardness from each other are welded together by use. of the laser beam or electron beam, it is possible to avoid a poor weld, which would otherwise cause a cracking in the high-hardness member.
| Inventors: | Nagaoka; Takahiro (Kakuda, JP) |
| Assignee: | Keihin Corporation (Tokyo, JP) |
| Appl. No.: | 666587 |
| Filed: | September 20, 2000 |
| Sep 24, 1999[JP] | 11-270684 |
| Current U.S. Class: | 219/121.14; 219/121.64 |
| Intern'l Class: | B23K 015/00; B23K 026/20 |
| Field of Search: | 219/121.6,121.63,121.64,121.82,121.85,121.13,121.14 228/232,234.1,262.41 |
| 4270496 | Jun., 1981 | Narasimhan et al. | 123/90. |
| Foreign Patent Documents | |||
| 411005183 | Jan., 1999 | JP | 219/121. |