Reduction of fume and gas emissions using innovative gas metal arc welding variants

Abstract

New environmental, health and safety legislation, both in the EU and in the USA, is driving the need for the study of new welding processes, and the selection of the operational procedures that will reduce fume emissions and will promote a healthier, safer and more productive work environment. Actually, there are a significant number of publications related with gas metal arc welding hazards. However, for the new gas metal arc welding hazards variants, especially cold metal transfer, there is no data available concerning fumes and gases emissions. This paper attempts to point out ways of reducing the harmful effects of gas metal arc welding processes using different filler materials, different shielding gases, different operational welding procedures and three welding processes: gas metal arc welding process and two variants, pulsed gas metal arc welding and cold metal transfer. The effect of nitrogen oxide addition to the shielding gas composition on the amount of welding fumes and gaseous emissions produced during welding is also analysed. The amount of fume and gases generated during welding was measured over a range of current intensity and arc voltages, using the standard procedures contained in EN ISO 15011-2 [1]. The data presented give a summary of the different gas metal arc welding variants and their relations to fume generation rates and gases emitted. The results obtained give indications on measures to be taken in order to reduce fume and gas emissions. In general, the minimisation of fume formation rate can be achieved by using lower energy gas metal arc welding variants, gas shielding with low CO2 and O2 contents and “green” wires.