Numerical Assessment of a Filtration Experiment Influenced by Microscale Carbon Monoxide Bubbles Arising in Steel Melt

Abstract

A numerical model based on the assumption that carbon monoxide bubbles form due to reaction between carbon and oxygen on the rough surface of inclusions is introduced to investigate the effects on inclusion removal. The proposed numerical model can be used to determine the growth of such carbon monoxide bubbles on an inclusion, which increases the rising velocity of the inclusion to reach the free surface of the melt faster. The results confirm that formation of carbon monoxide bubbles on the surface of inclusions can considerably increase the number of inclusions removed and thereby improve the cleanliness of steel melt.

Numerical Investigation of Filtration Influenced by Microscale CO Bubbles in Steel Melt

“…Table shows a comparison between the level of melt cleanliness η in case of bubble formation on filter walls with that in case of bubble formation on inclusions, published by Asad et al…”

“…The bubbles do not follow the flow melt and cannot be distributed in the flow field. Table 1 shows a comparison between the level of melt cleanliness η in case of bubble formation on filter walls with that in case of bubble formation on inclusions, published by Asad et al [29] Table 1 contains the results for the exponential and linear increase in bubble volume. Moreover, the results without an increase in bubble volume can be found in Table 1 as well.…”

“…This is attributed to the rising bubbles near the filter in this case, as shown in Figure 5b. On filter On inclusions [29] Linear increase On filter On inclusions [29] Linear increase Figure 6. Comparison of the instantaneous velocity field at t ¼ 5 s between the studied cases.…”

“…The reaction between C and O may take place either on the filter surface or on the inclusions surface. Asad et al investigated this reaction and the formation of CO bubbles on inclusions . The authors reported that this reaction and the formation of CO bubbles on the inclusions surface considerably increase the level of melt cleanliness and the cleaning efficiency.…”

Effect of Filter Functional Coating on Detrimental Nonmetallic Inclusions in 42CrMo4 Steel and Its Resulting Mechanical Properties

“…Next, ceramic foam filter was dipped 60 mm deep into the center of the crucible with the melt and rotated along its own central axis with 30 rpm for 10 s. The reaction between the filter and the melt was enhanced by induction currents with the turbulent melt flow up to 4 m/s. Detailed analysis of the flow conditions are given by Asad et al [23] After the 10 s reaction, the filter was removed and the melt was cooled down. Each filter type was immersed once in an individual steel melt giving four different batches, each treated with the different filter.…”