Approaches for a better understanding of the formation and reduction of welding fumes in GMA welding under consideration of innovative welding processes

GMAW processes are of very great economic importance in mechanised and automated production. Despite the great technical advancements during the last years, the acceptance of the process suffers from high emissions, particularly from welding fumes. Welding fumes are airborne particles which mainly consist of metal oxides. Moreover, radiation and gases are emitted. The exposure of welders and operators to fumes and gases is currently reduced by extraction systems, extraction torches and breathing masks. Although the arc process is the source of emission, the process itself has not been developed specifically with regard to low fume formation rates until now. As basic research for future low-emission GMAW processes, investigations into the formation mechanisms of welding fumes were carried out in the EWM Award “Physics of Welding“. Despite the variety of fume measurements in the past, the causal mechanisms are not fully understood yet. Only with the understanding of these mechanisms can effective strategies be derived to counteract the formation of emissions and to reduce the hazard potential of the process. In the first place, investigations were carried out into pulsed processes which are known to emit few welding fumes. The pulsed arc offers many adjustable process parameters in comparison to short arcs and spray arcs. Subsequently, experiments with conventional and modified (reduced-energy) short arcs as well as experiments with conventional and modified (forced) spray arcs were carried out in order to investigate the potential of modern variants for reducing welding fume emissions. The results show that the fume emissions of GMAW processes and therefore the hazard potential for welders and operators can be reduced significantly.