Investigation on Crystalline Materials in Welding Fumes of Covered Electrodes

Abstract

Crystalline materials in welding fumes of covered electrodes have been identified by X-ray diffraction method. Nine test electrodes have been prepared with covering. of single component material, MnO₂, Fe₂O₃ or SiO₂ using various binding agents. Five commercial electrodes including three types of non-lime electrodes and two types of lime electrodes have been used. The fume of tested electrode covered with MnO₂ or Fe₂O₃ consisted mainly of MnFe₂O₄ or Fe₃O₄ respectively. Fe₃O₄ and amorphous materials are formed, in the fumes of tested electrode covered with SiO₂. The fumes of. non-lime electrodes consisted mainly of Fe₃O₄. MnFe₂O₄ was also found in ilmenite type. Since these fumes contained about 20% SiO₂ other elements seemed to form amorphous materials together with SiO₂. The X-ray diffraction pattern of the fumes of lime type electrodes were so complicated that they were separated into water soluble, magnetic and non-magnetic materials. KCaF₃, NaF, CaF₂ and Fe₃O₄ were identified as the main crystalline materials in the fume of general lime type. NaF, CaF₂, MgO and Fe₃O₄ were identified in the fume.of modified lime type. As soluble materials, K₂CO₃ or Na₂CO₃ was found in general type or modified type respectively. Both lime type fumes contained a little amount of chlorine as KCI.