SYSTEM APPROACH TO DETERMINING THE EFFECT OF RARE-EARTH METALS ON THE STRUCTURE OF ROLL CAST IRONS

Abstract

The aim of the study is to determine the carbide-forming ability of various rare-earth metals in white roll cast irons. To achieve this goal, the following task was formulated: to establish the influence of chemical elements of the cerium and yttrium subgroups of rare-earth metals on the microstructure of roll cast iron, as well as to substantiate the selection of rare-earth metals for the treatment of white roll cast irons.

Regularities of the influence of rare-earth elements of the cerium subgroup (samarium and cerium) and the yttrium subgroup (gadolinium and yttrium) on the structure formation processes of white cast irons for rolling rolls under cooling rates typical for roll casting molds have been established. It has been shown that the individual effects of the studied subgroups of rare-earth metals on the microstructure differ in terms of their residual content ranges.

Modification of white cast iron with rare-earth metals leads to changes in the type of carbide eutectic and the dispersion of pearlite. It has been established that the carbide-forming ability of rare-earth metals of the yttrium subgroup is 5.2 times higher than that of the cerium subgroup. This made it possible to substantiate the composition of the base of a complex modifier to achieve the required properties of roll materials.