Effect of heat input on the hazardous gas emissions from galvanized steel during cold metal transfer welding

Abstract

The impact of heat input on the hazardous gas emissions of cold metal transfer welded zinc-coated steel joints is the main focus of this study. The bulk formation of fumes during the arc-assisted metal joining process not only affects the characteristics of joints but also, affects the welder’s respiratory systems and environment. Hence, in this research work, using a stack-monitoring kit the welding fumes are collected for various heat inputs and characterized to understand the hazardous emission from zinc-coated steel by the Cold Metal Transfer - 400TPSi advanced technique. The experimental work conducted for the heat input of 0.624 kJ/mm showed superior results for fume formation rate, dust emission rate and emission factor when compared to other heat inputs. In addition, the dust emission rate and fume formation rate increased as the heat input increased. Also, Hazardous gas emissions of CO2, SO2, CO, Zinc and the concentration of total dust for the corresponding heat input were found to be within permissible limits. Furthermore, the TEM analysis exhibits that, the particle structure of the fume is agglomerated chains of spherical and faceted morphology. The outcomes prove outstanding results when compared to other welding processes and norms of the NIOSH and ISI 5182 standards.