Effects of complex modifiers on the structure of gray and bleached cast irons

It is shown that one of the promising directions for improving the quality and ser-viceability of rolling rolls due to the improvement of the structure and properties of all zones of massive castings used for their production is the modification of cast iron. A significant improvement in the structure and properties of white cast iron is ensured by modifying them with rare-earth metals (REM), and gray ones by REM and magnesium. There is information that. REM and complex modifiers on their basis are increasingly used in rolling production. The need for studies of the influence of complex modifiers on the preparation of forming tools with a stable structure and inclusions of globular graphite was noted. The effect of complex modifiers on the structure and properties of cast irons was studied. The methodology of research is outlined. Investigation of the influence of the amount of complex modifier introduced on the structure of cast iron (from 0,94-1,01% Si) and gray (with 1,58-1,66% Si) cast iron. It is established that the modification of REM allows a wide variation in the structure, hardness, and physico-mechanical properties of white and half-rolled cast iron. The metallographic studies performed show that the optimal amount of the complex modifier with a content of at least 40,6% REM in the treatment of cast iron is 1,5-2,0%, which corresponds to the assimilability of 0,25-0,30% ΣREM. In gray cast iron, the amount of cementite is in the range 25,3-27,2% when casting into a chill. In bleached pig iron, the amount of cementite increases from 29,0 to 31,4%, and there is no graphite. In the structure of bleached cast iron casted in sandy-argillaceous forms, the proportion of cementite is in the range from 27,7 to 30,0%. It has been established that the use of Ce and La in the modification of the pre-eutectoid cast iron of the working layer at a content of 0,064-0,105% ΣREM pro-motes the formation of graphite of the vermicular form. With a content of 0,122-0,315% ΣREM, a compact and vermicular graph is formed. It is shown that modifying the REM does not ensure the production of graphite of a spherical shape for gray iron in the core, as in the case of magnesium modification