Oxidation Equilibria In Electric Arc Furnace Liquid Steel Under Low V-Ratio Practice

摘要

This work was initiated because electric arc furnace practice in steel foundries is somewhat different than in wrought product shops. In U.S. steel foundries, about 50% employ acid refractory practice and others employ basic practice, but at lower V-ratios than occur in electric furnace operations for wrought product due to sand on the returns that are remelted and limited slag volume for additions of lime. Basic refractory practice accompanies slags with V-ratios between 1.0 and 1.8. The paper details the use of oxygen equilibria in the steel during meltdown as an indicator of the oxygen activity in the slag and its relationship to macro-cleanliness in steel castings. A spreadsheet model was developed which takes into account chain scission in the silicate rich slag as a measure of oxygen activity when oxygen activity is controlled by silicon. A branching function was used to account for cases in which oxygen activity is controlled by carbon. The controlling oxygen activity correlates well with macro-cleanliness.