| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a laser-beam build-up method, which hardly produces blowholes so as to eliminate the generation of a crack in a built-up part and the exfoliation of the built-up part from a metallic base material. <P>SOLUTION: A copper alloy powder 16, which is supplied to a seat face 26 of a cylinder head 12, is irradiated with a laser beam 34, and simultaneously a shielding gas is discharged to the face. The shielding gas is a mixture of argon and helium that is added to the total of argon at a ratio of 0.1-10 vol%. In this case, a molten pool 52, which is produced due to melting of the copper alloy powder 16, is widely covered with a plasma cloud 50b and consequently the temperature rise of the molten pool 52 is accelerated. A built-up part that is formed by cooling and solidifying the molten pool functions as a valve seat. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
