PURPOSE: To prevent the exfoliation of build-up weld metal by building up a 1st layer by a reverse polarity plasma arc welding method and building up the ensuing layers up to the final layer by a gas welding method.
CONSTITUTION: A base metal 1 consisting of a corrosion resistant metallic plate is slightly inclined and fixed and is subjected to the reverse polarity plasma arc welding successively upward from the lower to the upper part in a flat horizontal position. Lead or lead alloy is used as a filler metal 2 at this time and a reverse polarity plasma arc welding torch 3 is used as a torch. Since the base metal 1 is inclined, the flow of the build-up weld metal in the passive film forming surface direction of the base metal 1 and the generation of defective joining are obviated and the adhesiveness of the metal is maintained over the entire surface. The base metal 1 is then positioned horizontal and subjected to the building-up by gas welding in a flat position. The joining force of the corrosion resistant base metal 1 and the build-up weld metal 4 is improved and the exfoliation thereof is removed by the above-mentioned method.
FURUYA MASAHARU
HIROWATARI TOMOYUKI
TOBATA SEISAKUSHO KK