PURPOSE: To form a bead having no defect such as lack of penetration or the like by detecting the quantity of the light radiated from the weld zone in the 1st layer while welding the groove of butted pipes under weaving without feeding a wire in the stage of welding the 2nd layer in the groove thereby controlling the welding of the 2nd layer so that the detected quantity of light attains the set quantity of light.
CONSTITUTION: The groove 2 of butted welding pipes 1, 1' is welded at the root pass by ordinary TIG welding. The 2nd layer is welded while a nonconsumable electrode 5 is weaved without feeding a wire 7. The radiant light emitted from the weld zone in the 1st layer heated by the arc of the 2nd layer is detected with a photoelectric photodetector 22 provided to a backing strip 10. At least one among welding current value, welding speed and the number of weaving of the electrode 5 are controlled during welding so that the quantity of the radiant light attains a preset reference quantity of light.
SATOU YUKIHIKO
SATOU YOSHIKAZU
| JPS5550969A | 1980-04-14 | |||
| JPS5619984A | 1981-02-25 |