Investigations on Decreased High Temperature Ductility of Different Continuously Cast Steel Grades

Continuous casting of premium steel grades requires a process with a high degree of precision and the knowledge about the mechanical behavior of the steel at temperatures above 800 °C. Herein, several origins of effects which lead to unwanted impairment of the hot strand shell like segregations, size, amount, kind, and distribution of precipitates as well as porosities from a metallurgical point of view are dealt. The systematic description of potential defect reasons helps to predict harmful operation parameters in context with the chemical composition of steel grades. A compilation of results from experiments at Department of Ferrous Metallurgy of RWTH Aachen University is complemented by a literature review. It is focused on the high temperature ductility and the underlying mechanisms inside the solidifying steel. Finally, potential measures to adjust the continuous casting process to prevent defects are elaborated. Methods to analyze high temperature mechanical behavior are summarized, and investigations from the IEHK are presented. Segregation, precipitation, phase transformation, and porosity represent inhomogeneities which are origins of brittleness during solidification and cooling. The complex interrelationships between internal and external parameters that weaken the material are discussed alongside with the importance of individual continuous casting parameters for crack‐sensitive steels.