Research of chemical composition of intermediate area of a bimetallic ESR ingot

A promising trend in materials science is the creation of composite materials with desired properties. The experimental material analyzed in this article is bimetallic composition obtained by electroslag remelting. ESR allows to solve the problem of obtaining bimetallic billets with high continuity of connecting layers. But the transition zone is an alloy of metals forming ingot layers and having properties different from alloyed metals. The transition zone represents another layer in the multilayer composition, the chemical composition of this layer is not constant, i.e. it changes in height and, consequently, in its properties. A large length of the transition zone often leads to the formation in this zone of adverse structures having properties different from those of remelted metal and forming electrode parts. The thickness of the transition zone is not uniform along the cross section of the ingot and its boundaries repeat the shape of the liquid metal bath. The existence of the transition zone makes it difficult to obtain a metal layer with desired properties and desired thickness. The article presents the results of the chemical analysis of the transition zone of the bimetallic ingot obtained by electroslag remelting. Concentrations of main alloying elements were determined in order to investigate their distribution in the bulk of the ingot, particularly in the fusion zone of dissimilar materials. To reduce chemical heterogeneity and a fusion zone length a number of measures were proposed aimed at reducing the depth of the liquid metal bath and changing the chemical composition of the transition zone. Particular attention in solving the problem of chemical heterogeneity and the length of the transition zone is given to the technology of electroslag remelting with consumable electrode rotation around its axis during the smelting process.