GRK 2802: Population of Nonmetallic Inclusions in Liquid High-Silicon Electrical Steel in Contact With MgO–C Refractories Based on Recyclates and Environmentally Friendly Binders

Abstract

Nonmetallic inclusions (NMIs) are integral constituents of ferrous materials, but almost always have a negative impact on their properties. Therefore, it is best to implement strategies during production to avoid NMIs as much as possible or at least control their formation. To gain a better understanding of these mechanisms, this study investigated the population of nonmetallic inclusions in liquid high-silicon electrical steel (Si 3 mass-%) depending on the contact with different MgO–C refractories. Both conventional refractory materials and those containing MgO–C recyclate and environmentally friendly binder systems, such as collagen, fructose, and lignin, were considered. Immersion tests were carried out for 30min at a temperature of 1600°C in accordance with DIN CEN/TS 15418. Surface phenomena, diffusions reactions, and corrosion mechanisms occurring in the refractory materials were characterized after the tests using SEM and EDX analyses. The change in the chemical composition of the steels was determined using spark spectroscopy, and the NMI population was evaluated after the tests using an automated feature analysis (AFA).