BACKING METAL FOR ARC WELDING AND ARC WELDING METHOD USING THE SAME

PROBLEM TO BE SOLVED: To provide a backing metal for welding used in welding a base material to the other metal by arc welding and capable of securely eliminating generation of a welding defect such as a gap generated at a welding start place, specifically at a bottom area of a groove part adjacent to an end tab. SOLUTION: A grooved end face of a grooved base material is made to be opposite to another base member to form the groove part therebetween, and the backing metal for welding is applied to both the base materials to form the bottom of the groove part when carrying out welding by filling molten metal in the groove part through arc welding. The backing metal for welding is formed of a long backing metal body that is longer than the groove part. An introduction groove extending from the outside of the groove part to the inside of the groove part and introducing the first layer of the molten metal from the outside of the groove part to the inside of the groove part is formed at least at one end surface. By the introduction groove, the first layer of the molten metal is arranged so as not to protrude from the surface of backing metal body in a part with which at least the bottom face of the end tab of the outside of the groove part of the backing metal body contacts. COPYRIGHT: (C)2011,JPO&INPIT