WELDING SOLID WIRE AND WELDING METAL

摘要

The objective of the present invention is to provide a similar-metal-composition welding solid wire, and welding metals therefor, with which both excellent bead shape and high ultra-low-temperature toughness for the weld joints can be achieved when welding 9% Ni steels together by means of a high-efficiency MIG welding method. A fixed ratio of a REM and O are included in a similar-metal-composition welding solid wire of a 9% NI steel base material, and oxygen is supplied in a trace amount in a range that does not hinder the ultra-low-temperature toughness of the weld joint (1a) but that is capable of forming fine REM oxides in the welding metal (3) and of controlling the welding metal to produce an excellent bead shape. In addition, both Al and Ti are regulated and an argon gas that contains little or no carbon dioxide gas is used as the shield gas in the MIG welding method. Thus, both an excellent bead shape and high ultra-low-temperature toughness for the weld joint (1a) can be achieved.