Dr. Peter Presoly - Characterization of hypo-peritectic steels by experimental methods and computational thermodynamics: An Overview
©EUROMAT 2021, 14 Sep 2021, Modern steel grades are subjected to constant development to perform weight reduction, energy-saving, and automobile safety performance. In the last decades, high strength and ductile steels were developed with increasing quantities of silicon and manganese. Three of these alloying concepts are Dual-Phase (DP), TRansformation Induced Plasticity (TRIP) and even TWinning Induced Plasticity (TWIP) steels. All these steel grades are based on the iron-carbon-manganese system with additions of ferrite former such as silicon and/or alumina, followed by micro-alloying elements. The main difference compared to previous steel grades are the significantly higher levels of ferrite formers. Apart from the research on these new steels' material and product properties, the knowledge about the production process, particularly the continuous casting (CC) and the initial solidification in a water-cooled copper mold, is of significant importance. In this regard, the high-temperature phase transformation temperatures and the thermodynamic properties play a particular role. An efficient pre-identification of hypo-peritectic steel grades by experiments or thermodynamics is relevant to ensure surface quality, productivity, and operational safety in the casting process. The potential of different laboratory experimental methods and thermodynamic approaches is critical evaluated in comparison with operational experience. Since process data in the continuous casting process often overlap with different operating influences (e.g. casting speed changes, width adjustments…), a new approach is presented to identify the process behavior of peritectic steels without additional effects. For this purpose, operating data from the mold monitoring were processed statistically, and only data areas with a steady-state casting length of more than 100 m were used for further consideration. Using this data preparation method, the peritectic area in the continuous casting process can be clearly described. Statistically prepared process data and experimentally verified thermodynamic data are the basis for the development and validation of demanding process models.