VERTICAL POSITION WELDING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a vertical position welding method which can efficiently realize high quality welding while suppressing the increase of a cost and keeping the strength by reducing heat input even in the case of thick steel plates. SOLUTION: An I-shaped bevel having a required narrow bevel gap is formed between edges of a pair of thick steel plates arranged in a vertical position. A welding wire projected from the welding torch of an arc welding machine having a constant voltage characteristic is inserted into the I-shaped bevel from diagonally above with respect to the thickness direction of the thick steel plates. The tip end of the welding wire to be fed from the tip end of the welding torch is reciprocated in the I-shaped bevel in the direction of the thickness of the steel plates by rocking the welding torch up and down. In this case, the projecting amount L of the welding wire from the welding torch is elongated or shortened while varying the feeding speed Vf of the welding wire such that welding current Iw becomes a target value, and further the feeding speed Vf of the welding wire is corrected so as to be added or subtracted according to the rocking direction of the welding torch (continuous line). COPYRIGHT: (C)2008,JPO&INPIT