Porosity reduction through a Ti particle based gap-paste in arc welding of zinc coated steel

Gap-paste is used to create gaps, for zinc vapor release, between the zinc coated steel sheets during the arc welding process. In-depth morphology analysis of the gap after the welding is presented which shows zinc oxide formation patterns are consistent with zinc vapor release through the formed gaps. Porosity analysis for four different mask configuration shows that the porosity of the sample, with 120 μm gaps created by the paste, is reduced from ∼15% to a near zero value. The tensile shear stress test reveals that the strength of the welded samples increased by ∼30% compared to that of the samples with no gaps. High-speed camera images are also presented showing the changes in the zinc vapor release mechanism when the paste is applied, and the various stages of zinc vapor release during the welding process are discussed.