Effect of Slag Composition on the Oxidation Kinetics of Alloying Elements during Electroslag Remelting of Stainless Steel: Part-2 Control of Titanium and Aluminum Content

Abstract

Kinetics of slag/metal reaction were investigated experimentally using 50 kg electroslag remelting (ESR) furnace in order to clarify the effect of slag containing different CaO and TiO2 content on titanium, aluminum and silicon content during the ESR process with 1Cr21Ni5Ti stainless steel. The results obtained show that the more CaO content in slag is, the more aluminum content in ingots increases. The lg([Al]4/[Ti]3) increases with the increase of slag temperature in the first 13 minutes during the ESR process, and after the slag temperature tends to be stable, the lg([Al]4/[Ti]3) decreases with the increase of TiO2 content in the rest process. The penetration and film theories were employed to analyze the rate determining step of slag/metal reaction, and it was found that the rate determining step of the reaction was the mass transfer of aluminum through the molten steel, silica through the slag and titanium on both of the metal and slag sides. The slag containing low CaO content combined with extra titania constantly added into molten slag in the first temperature-rising period is suitable for electroslag remelting of 1Cr21Ni5Ti stainless steel with high titanium and low aluminum content.