Dissimilar buildup welding method and dissimilar overlay clad structure

PROBLEM TO BE SOLVED: To provide a different material build-up welding method which can obtain a build-up weld zone of superio quality free of weld cracks or brittle structures, and is effective to enhance welding efficiency, and to provide a and different material build-up welding structure using the method. SOLUTION: The different material build-up welding method is characterized in that, on the surface of a carbon steel base material 5, a welding wire 6 of SUS309 system is built-up by welding by hot wire TIG welding of a wire energizing/heating method to form a build-up weld zone comprising a plurality of weld passes and a plurality of layers, and that the rate of dilution of fusion on the base material 5 side relative to each welding cross section of the weld passes is set ≤30% so that the molten metal structure of the build-up weld zones b1-b6 of the first layer becomes a mixed structure of an austenitic structure and a ferrite structure of 3-15%. Also, in the method, a low-carbon steel welding wire is underlaid on the surface of the carbon steel base material, with build-up welding of a stainless wire performed as above on the underlaying surface. COPYRIGHT: (C)2011,JPO&INPIT