To prevent generation of welding defects accompanying the fluctuation of a root gap by controlling so as to attain proper welding conditions corresponding to a root gap based on an estimated result.
Using, as a reference, So, an arc sensor signal ΔSc at the time of a root gap G=2mm, the size of So is compared with Sd, an arc sensor signal corresponding to the actual root gap. If Sd>So, the root gap is discriminated as large, and vice versa. The relation between the root gap and the output of the rotary arc sensor is set as a data base and registered. On the basis of such output information of the rotary arc sensor that is obtained from highspeed rotary arc welding, the root gap is estimated by computation. The control is done so as to attain proper welding conditions corresponding to the root gap based on that estimated result. As a result, it is possible to estimate the condition and tendency of root gap fluctuation based on the output information of the rotary arc sensor.
MURAYAMA MASATOMO
KANJIYOU YOSHIHIRO
SUGITANI YUJI