Quantitative and Qualitative Aspects of Gas–Metal–Oxide Mass Transfer in High-Temperature Confocal Scanning Laser Microscopy

Abstract

During high-temperature confocal scanning laser microscopy (HT-CSLM) of liquid steel samples, thermal Marangoni flow and rapid mass transfer between the sample and its surroundings occur due to the relatively small sample size (diameter around 5 mm) and large temperature gradients. The resulting evaporation and steel–slag reactions tend to change the chemical composition in the metal. Such mass transfer effects can change observed nonmetallic inclusions. This work quantifies oxide–metal–gas mass transfer of solutes during HT-CSLM experiments using computational simulations and experimental data for (1) dissolution of MgO inclusions in the presence and absence of slag and (2) Ca, Mg–silicate inclusion changes upon exposure of a Si–Mn-killed steel to an oxidizing gas atmosphere.