9th ECCC European Continuous Casting Conference – ECCC 2017

Continuous casting with bow type as well as vertical machines achieves high productivity and yield at high casting speeds. Nevertheless the speed is limited by metallurgical machine length and required cooling rates to achieve continuous production. This high cooling rates cause pronounced radial orientation of the crystallization front in the strand. Thus particularly at special high alloyed steel grades the strand center gets sensitive for higher porosity and segregation. In comparison conventional ingot casting has low productivity and yield operating at low cooling rates. These low cooling rates cause an axial orientation of the crystallization front in the strand and lead to best inner quality at special high alloyed steel grades. The objective of the Primetals Technologies Semi Continuous Casting technology is the combination of the benefits of ingot casting and continuous casting for production of most special grades like tool-, die steels and stainless steels with improved quality like core tight bloom structure, minimization of center cracks and highest cleanness together with optimized yield. This is achieved by using technological key points like mold and oscillator of conventional continuous casting for optimum surface quality and minimized OPEX, dynamic heat shielding and hot topping for slowest cooling rates in combination with dynamic strand stirring and advanced process models like DynaPhase and Dynacs 3D for dynamically controlled cooling to achieve excellent inner quality. This paper will discuss different concepts of semi-continuous casting machines for small and big sections showing benefits in quality, yield, operation, investment and running costs compared to continuous as well as ingot casting processes.