Abstract
The construction assembly and the repair of steel constructions painted with protective coatings are often carried out using arc welding. During the welding process, the coating in the weld zone is degrading. The protective coatings breakdown products are involved in the pore and non-metallic inclusion formation in the weld, the composition and distribution study of which makes it possible to analyze the reactions occurring during the welding. In this study, welding beads were deposited on the coated sheet surface by MAG welding. The distribution of inclusions (the average diameter and the relative content) along with the porosity in different bead zones were investigated by optical and scanning electron microscopy and digital image processing, and the chemical composition of inclusions was determined using energy-dispersive X-ray spectroscopy. The amount of diffusible hydrogen in the deposited metal was estimated with the vacuum method. In this work, four organosilicate coatings grades, differing in their purpose and heat resistance, were used, and their effect on the weld was studied.
Highlights
The aim of the present study was to investigate the distribution, composition, and morphology of the organosilicate coatings (OSCs) breakdown products in the form of non-metallic inclusions and to determine the amount of diffusible hydrogen in the weld metal to clarify the recommendations for OSCs application
The amount of diffusible hydrogen the H2 metal general, for the mild steel utilized in this study, the increased content of diffusible where [H ] is the concentration of hydrogen in the solution; PH2 —hydrogen pressure in hydrogenxin the deposited metal is not an issue
The amount of excess hydrogen released during the OSCs degradation does not exceed the limiting values of the hydrogen solubility in liquid steel
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Due to a number of unique functional properties, organosilicate coatings (OSCs) are required for the nuclear power industry constructions [1,2,3], for instrumentation [4]. For anti-icing protection [5], including utilization in the Far North [6]. OSCs are used for the anticorrosion protection of bearing and enclosing constructions, reinforced concrete constructions and anchor bolts of railway contact network support foundations [7]. The problem with the OSCs behavior during installation and repair works, performed by arc welding, is still relevant when OSCs are used to protect metal constructions. One of the pioneers of the organosilicate materials technology, N.P
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