| 摘要 |
PURPOSE:To join surely beginning and end parts and to unify the bead shape by increasing or decreasing the distance between an electrode and a base metal according to the rise and fall of the respective current values when TIG welding to be accomplished without filler metal starts and stopped. CONSTITUTION:An electrode is detached from a base metal while the welding current, designated as I1(amp), with respect to the distance L1(mm.) between the electrode and the base metal is increased at a grade of I3 per second right after the start of welding at the point T1 of the time when TIG welding to be accomplished without filler metal starts. Said distance is increased up to a stationary value L2 at the point T2 of the time when the current attains the value I2. The stationary welding is performed under the condition of the current I2 and the distance L2 and while the current is decreased at a grade of I4 per second at the point T3 of the time just before the terminal end part, electrode is approached to the base metal. The welding is ended at the point T4 of the time when said distance attains L1. The electrode is run simultaneously with firing. The beginning end part and terminal end part of welding are thus surely joined and the beads are formed to a smooth surface. |
