Effect of Nozzle Base Material on the Rate of Clogging during the Continuous Casting of Aluminum‐Killed Steels

Abstract

One approach to solving the problem of nozzle clogging during the continuous casting of aluminum-killed steels is through careful selection of nozzle materials. In this study, the rate of clogging was measured while casting steel through simulated nozzles produced from alumina, zirconia, magnesia, zirconia-graphite, and alumina-graphite -three common base materials and two common carbon-containing nozzle materials. Spent nozzles were characterized using optical and cathodoluminescence microscopy. Interactions between the nozzles and steel were not observed in the alumina, zirconia, and zirconia-graphite nozzles. Slight interactions were observed in the magnesia nozzles as alumina inclusions within the steel interacted with the nozzle to produce alumina-magnesia spinel. Greater amounts of interaction were observed with alumina-graphite nozzles. No statistical differences in the mean rate of clogging were observed between all of the pure oxide nozzles and Zirconia-graphite nozzles. However, the alumina-graphite nozzles clogged at a much higher rate than the other nozzles. The higher rate of clogging is thought to be due to refractory-steel interactions.

Pilot plant study of nozzle clogging mechanisms during casting of REM treated stainless steels

“…The oxide phase density was set to 6500 kg m 23 , m was 350 kg and f C was calculated to be 0?34. Hence, the amount of clogging network was calculated to be 70 cm 3 . From the nozzles shown in Fig.…”

“…2 Furthermore, it was found to be independent of whether zirconia, alumina, alumina graphite or magnesia was used as a nozzle material. 2,3 Freezing and reoxidation of the steel was also suggested as a probable clogging mechanism, and an oversized nozzle was suggested as a possible solution to decrease clogging. 2 It has also been found that steels in which a solid oxide phase is stable suffer from clogging, while steels with only liquid oxide phases do not.…”

Casting Simulation of Calcium Titanate and Calcium Zirconate Nozzles for Continuous Casting of Aluminum-Killed Steels

“…To aid analysis, a clogging factor (CF) for each data point in the mass cast data was calculated per the methodology developed by Trueba. [15] The CF is a ratio of the actual mass flow rate through the nozzle at time t to the theoretical mass flow rate through the nozzle at time t based on the discharge coefficient determined from the initial mass flow through the nozzle. The mass flow rate for flow through an orifice is…”

Turbulent Flow Phenomena and Ce2O3 Behavior during a Steel Teeming Process

“…The reasons for the clogging and the possible countermeasures to prevent clogging have been extensively studied. [1][2][3][4][5][6][7][8] Some research has been carried out to remove inclusions in molten steel during a ladle treatment as well as during a tundish operation. [9][10][11][12] However, it is impossible to obtain a completely clean steel with the current steel production technology.…”