PURPOSE: To form a lap joint part in a defectless and satisfactory state in CO2 arc semi-automatic welding for one side of lap steel plates by a nozzle mounted with legs for maintaining the specified projecting length of a wire by segmenting welding time of specific stages or above and executing welding respectively at different electric current values.
CONSTITUTION: The lap steel plates 4 are subjected to CO2 arc semi-automatic welding by the nozzle 8 mounted with the legs 10 for maintaining the specified projecting length of the wire. The entire welding time T is segmented to ≥5 stages and the welding is executed at respectively the different current values in this case. The plates are first preliminarily heated at the low current value A2 during the time T1 from the arc start time S1 till S2 then the weld is deeply penetrated uniformly at the high current value A1 during the time T2 between S2WS3. The solidification is relieved again at the current value A2 during the time T3 between S3WS4 to prevent the generation of blow holes from between the lap steel parts. The current is decreased to the low value A0 to concentrate gas buffles, etc. to the central part during the time T4 between S4WS5 and the current is again decreased to the value A2 to remove the defects remaining at the center during the time T5 between S5WS0. The lap weld zone is thus satisfactorily welded without detects by the above-mentioned stage.
FUKAHORI KOUZOU
KISHIKAWA HIROYUKI
OKABE YOSHITO
HIRAKO WATARU
| JPS52120940A | 1977-10-11 |