THE INFLUENCE ELECTROSLAG HARD-FACING ON THE CHEMICAL COMPOUND OF NONMETALLIC INCLUSIONS AND FUSION ZONE

Abstract

Purpose. As a result of the study, it is necessary to determine the factors that influence the chemical composition of the fusion zone and non-metallic inclusions during electroslag surfacing, which is used in the restoration of railway transport parts, namely electric locomotives of the ЧС-4, ЧС-6, ЧС-8, etc. brands. Research methods. The chemical composition of non-metallic inclusions was studied using the CAMECA X-ray spectroscopic microanalysis unit and the "SUPRA 40 WDS" scanning electron microscope manufactured by Carl Zeiss (Germany). The measurement error is no more than 1 %. The nature of non-metallic inclusions (microstructure, morphology and topography) was studied by the petrographic method using a complex methodology. Samples for research were cut from the metal of the experimental deposits in such a way that the fusion zone was located in the middle of the sample. Chemical etching of the metal with a 4% solution of sulfuric acid was carried out to identify the fusion zone. Results. As a result of the study of the chemical and mineralogical nature of non-metallic inclusions, it is shown that in the base metal (Ст.3 steel) when approaching the fusion zone, the number and size of non-metallic inclusions decrease, as well as their shape, microstructure and composition change. There are practically no non-metallic inclusions in the heating zone (immediately near the fusion zone). Scientific novelty. It is shown that the content of elements from the base metal to the deposited metal practically does not change, with the exception of chromium, the content of which gradually increases from Ст.3 steel to 12X13 steel in the fusion zone. Practical value. The results of the work make it possible to explain the effect of electroslag restoration of electric locomotive parts on the quality of the fusion zone and to explain the mechanism of structure defects and possible types of non-metallic inclusions as a result of surfacing.