Contact angle and adhesion of CaO-SiO2- and CaO-Al2O3-based mold slags on solid steel of various compositions

Abstract

To evaluate the lubrication capacity and flaking behavior of mold slag during continuous casting, the contact angle and spreading of CaO-SiO2 and CaO-Al2O3-based mold slags on solid substrates of three steel grades were investigated systematically by the sessile drop technique. The optical basicity and viscosity were combined to clarify the relationship between melt structure and contact angle, and the Mills’ model was used to determine the work of adhesion of mold slags on steel substrates. The primary results indicated that an increasing content of Al and Mn in steel was favorable for decreasing the contact angles. The wettability of the mold slags was related to the network structure, where a more complex network structure, correlated with a larger contact angle on the solid steel surface. The separation of the low-reactive or non-reactive mold slags from the solidified shell was more difficult than that of the CaO-SiO2-based mold slags. Considering the contact angles and works of adhesion, the developed low-reactive or non-reactive mold slags could present both satisfactory lubricating capacity and flaking behavior from the strand surface.