| 摘要 |
<p>In the present invention, a welding voltage output when performing plasma arc keyhole welding is detected, and the frequency of the welding voltage is controlled so as to substantially match the natural frequency oscillation (for example, 30-40Hz) of a weld pool (P) formed on the rear surface side of a matrix (15). This configuration enables the frequency of the weld pool (P) to be easily controlled so as to substantially match such natural frequency oscillation and as a result when performing plasma arc keyhole welding a stable penetration bead of a constant height can be reliably obtained.</p> |
