20th International Forgemasters Meeting - IFM 2017

Various routes for manufacturing of high quality steel grades at small to medium batch sizes are examined. Special attention is paid to process features with respect to refining flexibility and production costs. It will be shown how the combination of cost effective melting furnaces with subsequently performed refining processes in a Vacuum Induction Degassing (VID) unit provide means to excellent and stable product quality. Today’s increasing material prices results in the use of more common less expensive scrap stock. Whereas minor quality scrap can be diluted in huge steel factories using batch weights above 50 t, smaller sized furnaces require additional features in melt treatment. High quality ingot production requires customized production lines due to material input and necessary refining steps. The VID furnace can be used as melting in or just as a refining unit whereas classical steel melting lines consists of Electric Arc Furnace (EAF), Ladle furnace (LF) and Vacuum Degassing (VD). The flexibility of a VID unit in modern steel melting shops without ladle practice will be presented. In first part of this paper an overview of refining capabilities during VID process is given. Results from decarburization and degassing routines at various batch sizes are presented. Furthermore, the impact on refining kinetics by enhanced melt bath movement will be revealed. Possible slag treatment procedures are described in detail with respect to removal of Sulphur. In second part customized design solutions to establish best means for cost effective high quality production are presented. Combinations of production routes of various melting furnaces with VID are presented and comparison of investment and operation costs among these different routes will be made.