The Effect of Gravity on the Weld Pool Shape in Stainless Steel

Abstract

To obtain a high quality weld we need to understand the mechanical and thermal properties of the material and its melt, and the solidification mode and its morphology. Convective flow during welding is dependent upon buoyancy, surface tension and its temperature coefficient (dγ/dT), the arc drag and electromagnetic forces, the shielding gas, and the viscosity of the melt. By controlling fluid flow and heat transfer during welding, one should be able to control the weld solidification mode, morphology and segregation, and by that, prevent defects in the fusion zone. Buoyancy and Marangoni flow are major factors in controlling weld solidification.^1,2 There is a lack of knowledge on the effect of gravity, especially macro-gravity (> lg), on weld pool geometry. Thus, the objective of this work is to evaluate the shape and profile of the fusion zone of 304 and 316 gas-tungsten arc welds during centrifugation.