| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress occurrence of black smut on a surface of a bead in an arc start. <P>SOLUTION: Welding wire is once brought into contact with a base material, and then the wire is separated from the base material with retreating feeding, so that an initial MIG arc in which initial arc current is electrified is generated. The retreating feeding is continued, resulting in arc length being lengthened, so that a plasma arc is generated. After that, switching to advance feeding, MIG welding current is electrified, thereby transferring to a stationary MIG arc. The value of the initial arc current is set to a first initial arc current value Ii1 during a term t3 to t31 from a point of occurrence of the initial MIG arc until the arc length La reaches a first reference distance Lt1, and during a subsequent term t31 to t4, a second initial arc current value Ii2 is set. The Ii1 is larger than the Ii2. The welding wire is melted by an arc to which the Ii1 is electrified, so that the arc length La is rapidly lengthened. Thus, the term when the MIG arc is singly generated can be lengthened, allowing occurrence of the smut to be suppressed. <P>COPYRIGHT: (C)2012,JPO&INPIT |
