Influence of the Oxide Films on the Weld Penetration Phenomena of Stainless Steel

With the purpose of improving penetration property of TIG welds of stainles steel, evaluation was made on the possibility to oxidize the stainless steel surface and to dope oxygen on the weld metal from oxide film. As a result, (d/W) ratio, which an index of penetration property, apparently increased by giving oxide film on stainless steel surface, and penetration could be remarkably improved. The effect of the oxide film to improve penetration property may be attributable to the fact. That the oxide film is decomposed by arc heat in high temperature portion of molten pool , thereby Increasing oxygen concentration of that region, and that this caused "positive" surface tension temperature gradient and Marangoni convection from centra] portion of the molten pool to the bottom portion thereof occurred.