Forging of Ingots Without Hot Tops

Geometric parameters of the shrinkage cavities in ingots without hot tops from the NKMZ and “Izhorskie zavodi” plants varying in mass from 1.6–180 tons with different ingot height to average diameter ratio have been studied. The influence of geometric parameters, solidification conditions, and steel chemical composition on the relative depth of the ingot shrinkage cavity was studied. The possibility of forging ingots without hot tops by using a preliminary upsetting by plates with holes using different configurations was studied. Theoretical research based on a FEM of ingot upsetting in flat, convex, and concave plates with holes has been conducted. Dimensions of instruments which allow the measurement of maximum local deformations in the ingot shrinkage cavity area during the upsetting process have been determined. Dependence of the relative deformation of upsetting ingots without hot tops upon geometric parameters of the instrument and the ingot parameters was determined.