GOUGINGLESS COMPLETE PENETRATION WELDING METHOD

PROBLEM TO BE SOLVED: To provide a gougingless complete penetration welding method by which a completely penetrated both side welded joint which is free from high-temperature cracking is obtained even to long-length joint which does not require a gouging step but requires tack welding for restraining the joint on the groove face. SOLUTION: In a gas metal-arc welding by which the complete penetration welding of a double groove joint without gouging by a preceding welding and a succeeding welding is performed, when performing the tack welding on the groove faces for restraining the joint, the tack welding is performed on the groove face on the side of the preceding welding of a root pass, regardless of the presence or absence of a tacking bead, the welding arc on the side of the preceding welding is not penetrated through the root face of the groove and the root pass on the preceding side is performed under welding conditions so that the root part of the groove is molten. In the succeeding welding, by welding the root pass succeeding side under such welding conditions that the depth of penetration becomes not less than the thickness of the root face of the groove and lapping the penetration on the root pass preceding side and the root pass succeeding side, the complete penetration in the root part of the groove is obtained without performing the gouging. COPYRIGHT: (C)2008,JPO&INPIT