| 摘要 |
PROBLEM TO BE SOLVED: To obtain a shield gas for MIG welding using nickel alloy as a welding wire with which a stable arc, excellent wettability and a uniform bead are obtained and to obtain a welding method of excellent weldability. SOLUTION: This shield gas for MIG welding using nickel alloy as a welding wire is a gaseous mixture which is prodused by incorporating three kinds of gaseous components consisting of, by vol.%, 25-85% gaseous helium, 0.1-1.0% gaseous oxygen or 0.2-2.5% gaseous carbonic acid into gaseous argon used as a basic gas or a gaseous mixture having a composition consisting of, by vol.%, 25-85% gaseous helium, gaseous oxygen (O2) and gaseous carbonic acid (CO2) in amount satisfying a relation 2.5(O2)+(CO2)=0.25-2.5% and the balance gaseous argon used as the basic gas. This method of MIG welding is performed with the welding wire of nickel alloy under the atmosphere of these shield gases. |
