State of the art and future outlook for continuous casting of steel

Abstract

Over the past 30 years, the continuous casting technology is developed to a safe and well-working process in steel production. In highly industrialized countries, nearly all steel grades are casted by this technology. As society and technology developed, the demand for metal goods increased and production took different routes. In the first process route, the present foundry industry retained the original near net shape fabrication, and produces complicated shapes from engine blocks to spectacle frames. In the second process route, ingot casting with subsequent rolling moved increasingly away from the geometry of the final product and served mainly for the production of mass products, such as sheets, bars, sections, and so on. The number of production steps needed to give the metals its final shape increased and the production costs rose correspondingly. This chapter discusses the development of the second process route, ingot casting/continuous casting up to near net shape casting. The in-time linking of casting area and hot strip mill is nowadays partially realized by direct slab charging, but its percentage is limited by different casting and rolling speed. An increase of the casting speed is achieved by reducing the casting thickness. The main target of near net shape casting is saving energy for rolling as well as reheating and by these means reducing production costs. In addition, the new small and flexible steel plants (mini-mills) afford less investment amounts. The first thin slab casters were commissioned some years ago and have shown remarkable improvements due to higher solidification rates. A further reduction of the casting thickness is the aim of many companies and institutes. First successful trials in pilot plants promise a breakthrough of strip casting.