Patent ID: 9403232
Filing Date: 2016-08-02
CPC Classification: B23K

Claim Text:
1. An arc welding apparatus that performs vertical-up welding by generating an arc in a groove between steel plates to be welded and forming a molten pool, the arc welding apparatus comprising: welding means for performing arc welding by generating the arc from a welding wire in the groove between the steel plates to be welded in a substantially vertically downward direction and forming the molten pool; lifting means for lifting the welding means in a substantially vertically upward direction relative to the steel plates to be welded; a welding power source that feeds current to the welding wire to generate the arc; speed control means for monitoring current output from the welding power source and, if a value of the output current is smaller than a value of current set in advance, controlling the lifting means such that rising speed of the welding means decreases or, if the value of the output current is larger than the set value of current, controlling the lifting means such that the rising speed of the welding means increases; and voltage control means for monitoring voltage output from the welding power source during the welding, obtaining information regarding the number of times that a value of the output voltage falls below a determination voltage, which is set in advance as a determination threshold, or periods for which the value of the output voltage remains below the determination voltage and, if the information regarding the number of times or the periods exceeds a set threshold, controlling the welding power source such that the value of the output voltage increases or, if the information regarding the number of times or the periods is below the set threshold, controlling the welding power source such that the value of the output voltage decreases.