CHVG40 Treated with Product Produced by NPP Technology: Large-Tonnage Casting Manufactured in Katav-Ivanovsk

March 2020 saw a large CHVG40 (CGI) casting weighing 3 tons manufactured at the Katav-Ivanovsk Foundry Mechanical Factory. The process during the course of which Vermiloy®538 nodularizer was used proved successful. Background information: The cast iron was melted in an electric arc furnace (ДСП-3). 80% of the charge materials used were foundry returns (scrapped SCH35 castings), the balance of 20% was scrap steel. 80% of the charge materials had a high sulphur content of 0.075%. Due to the high sulphur content, Refloy®FM briquetted refiner was initially used for desulphurization purposes, i.e. the rare- and alkali-earth metals contained in the refiner promote removal of sulphur and other deleterious elements from the melt. Refloy®FM also contributes to the deoxidization of molten metal and its alloying with silicon. Refloy®FM briquetted refiner (20 kg/t) was placed in the bottom of the furnace, and as a result the sulphur content was decreased by a factor of 2. In order for the compacted graphite to have the required shape in the finished casting, the liquid iron transferred into a ladle was treated with Vermiloy®538 nodularizer. Preliminarily, the liquid iron was treated with SIBAR®7 barium-containing inoculant as it was being tapped into the ladle. Though the content of sulphur in the finished casting was over 0.025%, which is above the limit for CHVG40, the treatment materials produced by NPP have made it possible to obtain compacted graphite of the required shape.