Influence of technological parameters of the welding process on aerosol release

Abstract

The purpose of this article is to assess the influence of the parameters of the manual and mechanized arc welding process on their hygienic characteristics and to identify the main factors that affect the release of welding aerosols. It is shown that during manual welding with covered electrodes, the level of aerosol release depends on the welding modes: welding current, polarity and arc voltage. Regardless of the type of electrodes used, an increase in the welding current leads to an increase in the level of harmful emissions. In contrast to welding with covered electrodes, the dependence of the level of aerosol release indicators formed during mechanized welding in protective gases with a consumable electrode on the welding mode is more complex – first, the intensity of aerosol formation increases to a maximum, then decreases to a minimum and increases again. It is shown that the process of aerosol formation consists of two stages: evaporation of metal in the arc zone and removal of part of the vapor beyond the arc, where they condense into solid aerosol particles. The removal of vapor from the arc zone is prevented by the immersion of the arc into the weld pool. Increasing the arc power first contributes to increased evaporation, and then to deeper penetration of the base metal, which minimizes aerosol release. Based on studies of weld pool macrosections, it was found that the shape of the weld pool also influences the complex nature of such dependencies. For each diameter of the welding wire, there are certain values of the welding current at which the maximum amount of harmful substances is released, and a range of current values that ensures the minimum intensity of their release. When welding at optimal modes, the level of aerosol release decreases when using wires of smaller diameter. The obtained research results show how the correct choice of welding materials, shielding gas and welding modes makes it possible to reduce the levels of harmful substance release.