Effect of steel deoxidation on chemical heterogeneity of large forging ingots

Purpose: theoretical and experimental investigation of the effect of deoxidation on formation of sulphide inclusions and development of eccentric liquation cords, elaboration of the process of production of large high-quality forging ingots on the basis of the established dependences. The work describes the effect of silicon and aluminium on the morphology, type and amount of sulphides and on the degree of development of cords. A mechanism of influence of the oxygen activity on the formation of sulphides is proposed. The work deals with the development of a new procedure for modelling the process of development of the cords, according to which an investigation was made in relation to the conditions of formation and rate of development of the cords, and to the effect of thermophysical, structural and chemical factors on these processes. A complex process of production of large rotor-steel forging ingots is developed and the process of production of super-large ingots having a mass of up to 420 t is optimized. These processes provide for the minimum development of the micro- and macrochemical heterogeneity in metal. More than 50 thousand blanks for welded rotors were made at the Energomashspetsstal works. More than 10 thousand super-large ingots were manufactured at the Izhorsky Zavod Production AssociationAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio