STUDY OF THE PECULIARITIES OF REDOX REACTIONS DURING ELECTROSLAG SURFACING USING MODIFYING IMPURITIES OF DIFFERENT CHEMICAL COMPOSITION
Authors:   State Biotechnological University, Ukraine, Rybalko Ivan , Zakharov Andrii ,   State Biotechnological University, Ukraine
Published: December 2023

The chemical composition of the deposited metal in electroslag surfacing is determined by the composition of the base metal and surfacing materials, as well as the course of metallurgical reactions between liquid metal, slag and gases. The actual content of impurities in the deposited layer differs from the calculated one due to the metallurgical reactions that occur during surfacing. It has been experimentally established that the content of manganese in the deposited metal depends on both its content in the deposited material and the amount of MnO in the slag. The presence of silicon in the deposited material increases the transfer of manganese from the slag to the deposited metal. The silicon content in surfacing materials usually does not exceed 2-3%. Manganese enhances the transition of silicon from slag to deposited metal. Titanium is widely used for alloying and modifying weld metal. Typically, its content in the weld metal is about 0.1-0.3%, with some wear-resistant steels having a content of up to 2%. In deposited metal such as high-chromium cast irons, the chromium content can reach 30...35%. The content of vanadium and niobium in wear-resistant alloy steels and alloys can be 7-10%. These elements are similar in chemical properties, and their oxidation by slag is caused by FeO. Cobalt, unlike tungsten, titanium, molybdenum, vanadium and chromium, does not form carbides. In the vast majority of cases, wear-resistant steels contain a significant amount of carbon. Carbon oxidation in the electroslag process can occur both due to oxygen contained in the liquid steel and due to manganese, silicon and iron oxides contained in the slag. Oxygen can enter the deposited metal in the form of oxides on the surface of the electrode materials and directly from the air through the slag. The final oxygen content in the deposited metal depends on many factors: the form and amount of oxygen contained in the source metal; the composition of the slag; the surfacing process, etc. The nitrogen content in the deposited metal depends on its initial content in the surfacing materials and the base metal, the chemical composition of the flux, the surfacing mode, etc. The aim of this work is to study the peculiarities of the course of redox reactions during ESP with various modifying additives of different chemical composition and to compare them theoretically with a new modifier – bentonite clay – to increase the wear resistance of working surfaces operating under accelerated abrasive wear. The methodology of the study is a theoretical comparison of already existing and widely used modifying admixtures, their properties and performance indicators with a new promising modifier – bentonite clay of a special chemical composition. The scientific novelty of the research lies in the special chemical composition of the new modifying additive, which significantly affects the quality of the deposited coating, thereby increasing the level of wear resistance by about 1.5-2 times. The practical significance of the results obtained is due to the increase in the level of wear resistance of the deposited and restored surfaces, and the economic feasibility of using bentonite clay as a modifier.