Solubility of Oxygen in Iron-Silicon Melts in Equilibrium with Silica at 1873 K

Abstract

The solubility of oxygen in iron-silicon melts in equilibrium with silica was measured within the range from 0.1 up to 70 mass% Si at 1 873 K. The experimental procedure involved alloys melting in silica crucibles under argon atmosphere. The sampling was made by melt sucking into quartz tubes, equipped with copper chillers. The oxygen content of analytical samples was determined with inert gas fusion analysis after careful sample preparation. The results obtained were treated by thermodynamic model, which allowed to calculated the activity and solubility of oxygen in Fe-Si melts up to 100 mass% Si.The isotherm of oxygen solubility exhibits both intermediate minimum and maximum at 20 and 85 mass% Si, respectively. The corresponding values of oxygen saturated contents are as follows: 1.4 and 94 mg/g. The activity coefficient of oxygen shows alternating deviations from the additive behaviour. These are positive in the iron rich melts, containing up to 45 mass% Si. In the melts with higher silicon content the deviations from additivity are negative. The following values of interaction parameters were calculated: e

Assessment of Si–O Equilibria and Nonmetallic Inclusion Characteristics in High Silicon Steels

“…[3,6,8] Although Al deoxidation of liquid steel has been widely studied, [2] the studies on Si-O deoxidation equilibria of liquid steel are somewhat limited. [1,9,10] Over the past several decades, many authors [1,[9][10][11][12][13][14] measured the total oxygen (TO) content in equilibrium with silicon content in liquid steel using high-temperature experiments and thermodynamic analysis. TO of steel melt can be defined as the sum of the dissolved oxygen content and the insoluble oxygen (oxygen present in the form of oxides/inclusions).…”

“…[1,12,13,16] The oxygen contents in equilibrium with this range of Si concentration show good agreement among the previous studies. [1,[9][10][11][12][13] Gokcen and Chipman [11] measured oxygen content in equilibrium with Si up to 15 wt%. The oxygen content measured [11] was relatively high compared with the recent study of Shibaev et al [9] Aleksandrov and Dashevskii [10] measured the oxygen solubility in liquid iron up to 5 wt% Si.…”

“…[1,[9][10][11][12][13] Gokcen and Chipman [11] measured oxygen content in equilibrium with Si up to 15 wt%. The oxygen content measured [11] was relatively high compared with the recent study of Shibaev et al [9] Aleksandrov and Dashevskii [10] measured the oxygen solubility in liquid iron up to 5 wt% Si. They [10] mainly focused on the influence of cobalt in Si-O deoxidation equilibria, whereas Suzuki et al [1] investigated the effect of Cr.…”

The Morphology and Chemistry Evolution of Inclusions in Fe-Si-Al-O Melts

“…Liu et al [6] used mathematical modeling to simulate the precipitation of a sulfide inclusion on preexisting oxide particles in a Fe-Si alloy. Shivaev et al [7] carried out experiments to determine the solubility of oxygen in Fe-Si melts at 1873 K (1600°C). In the review by Park et al, [8] the various effects of the deoxidation condition on the formation of spinel inclusions are summarized, and the effects of impurities in ferro-silicon are described.…”

“…However, strategies have been developed to alter inclusions such that they can be used to control phase transformations to improve mechanical and physical properties in steel. [1][2][3] The published work [4][5][6][7] on inclusions is limited in the case of high silicon-bearing steels, such as oriented and nonoriented electrical steels and transformation-induced plasticity (TRIP) steels, even though the microphase structure related to inclusions is complex and important. Choudhary et al [4] studied the inclusions in Mn-Si deoxidized steel from the viewpoint of nozzle clogging.…”