THE INFLUENCE OF THE MICROSTRUCTURE AND CHEMICAL COMPOSITION OF CAST IRON ON THE RESISTANCE OF FERRO-ALLOY MOLDS

Abstract

The article discusses the actual problem of increasing the operational resistance of molds used in the production of ferroalloys. The molds are operated under conditions of intense low-cycle thermal effects, which leads to thermal stresses, oxidation, decarburization, erosion of working surfaces, the formation of a grid of heat, cracks and warping, resulting in a high specific consumption of molds per ton of alloys produced. The purpose of the study is to establish the relationship between the operating conditions of the molds and the properties of the material from which they are made. The paper analyzes in detail the effect of the chemical composition and microstructure of gray cast iron on its physical and mechanical properties and the resistance of the molds. Special attention is paid to the role of carbon, silicon, manganese and chromium: an increase in the carbon and silicon content contributes to the formation of a ferrite-pearlite structure with a large amount of graphite, which increases ductility and thermal conductivity, and an excess of chromium leads to the formation of cementite and reduced performance properties. The research methodology includes an information and analytical review of the scientific literature, as well as metallographic studies of the material of molds with different service life, performed using a modern microscope. The relationship between the microstructure and the causes of destruction has been revealed. The main results of the study revealed key factors affecting the durability of the mills, including the chemical composition of cast iron, microstructure features and operating conditions. The optimal microstructure of the material has been established, ensuring maximum durability of the molds. The practical significance of the work lies in identifying promising areas for improving the technology of mold production, in particular, in the field of liquid-phase treatment of melts before casting. The results obtained can be used to increase the efficiency of foundry production, reduce their tendency to fracture, and extend the service life of molds.