| 摘要 |
PROBLEM TO BE SOLVED: To reduce generation of spatter due to vibration of a molten pool in an electric current control method at the time of detecting constriction, wherein a welding current is rapidly reduced immediately before re-generation of an arc by detecting constriction of a droplet during a short-circuit period Ts in short-circuit transfer welding. SOLUTION: In the electric current control method at the time of detecting the constriction, a phenomenon of droplet constriction as a sign of an arc regenerating from a short-circuit state Ts is detected through a change in voltage Vw or resistance between a consumable electrode and a base material. When this constriction phenomenon is detected, a welding current Iw for energizing the short-circuit load is rapidly reduced so as to keep a constriction current Im low. When the arc is regenerated, the welding current Iw is increased, at that point of time or after a lapse of a prescribed delay period Td, from the low constriction current Im to a high arc current Ih, and supplied to the arc load. In this method, the welding current Iw is increased from the low constriction current Im to the high arc current Ih, with a predetermined slope S retained for reducing vibration of a molten pool. COPYRIGHT: (C)2006,JPO&NCIPI
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