Presence of non-metallic inclusion deteriorates quality of steel and causes nozzle clogging during casting. Nozzle clogging eventually leads to a disruption of normal casting operations. This happens when solid alumina inclusions get accumulate in the nozzle of submerged entry nozzle (SEN). Therefore, it is required to understand the inclusion characteristics (shape, size and chemistry), which forms during the steelmaking process. Calcium is added in the steel ladle furnace (LF) in the form of CaSi wire to modify inclusions and to desulphurize steel. The range in which all the oxides become liquid and no solid sulphides begin to form is regarded as the "optimum window" or “liquid inclusion window” for calcium treatment. It is a target to obtain this calcium addition window, during calcium addition in the ladle furnace. This window mainly depends on the sulfur and total oxygen contents of the liquid steel bath. In the present study, inclusions characteristics such as volume fraction of inclusions, inclusion rating and EDS analysis of inclusions has been carried out using SEM-EDS. Thermodynamic study is carried out using thermodynamic software FACTSAGE and databases to find out formation of various calcium aluminates and the precipitation of CaS. Results show that liquid inclusion window mainly depends mainly on the sulphur level, total oxygen and aluminum content in the steel. These windows will help in calculation of calcium addition range for optimizing the addition of calcium in the ladle. These nomograms have been validated with actual plant condition to reduce the nozzle clogging during continuous casting.

The influence of surface roughness and impact energy on the hydrodynamic behavior of water droplets impinging upon dry and rigid surfaces of known roughness has been investigated experimentally. The influence of these two parameters on the droplet maximum spreading diameter, slip length during droplet recoil, dynamic contact angle, contact angle hysteresis, and apparent contact angle of droplets at rest has been determined. Based on the quantitative assessment, a correlation for the maximum spreading diameter in terms of the nondimensional parameter (We/Oh) and surface roughness ratio (R a/d o) was derived. We propose to use surface roughness “R a” rather than using the contact angle for correlation as contact angles cannot be known a priori, whereas surface roughness can be determined beforehand. The wetting state of a droplet depends on the combined influence of droplet impact energy and surface roughness. While increasing impact energy increases the spreading, higher surface roughness resists the droplet from spreading. Low impact energy and a smoother surface tend toward the Cassie–Baxter wetting state, whereas high impact energy and rough surfaces propel the droplet toward the Wenzel state of wetting.

Steel melters who use recycled steel scrap in small induction furnaces have no control on phosphorus input from scrap. For furnaces of capacity less than 2T, dephosphorisation in external ladle is not possible owing to excessive heat loss. Studies on dephosphorisation were thus carried out in the induction furnace itself using lime based fluxes with and without addition of fluxing agents like CaF 2 and Na20. The fluxes were added directly and also added through injection. The effects of individual components of fluxes on dephosphorisation were estimated. Correlation were developed between dephosphorisation and different expressions of basicity values. An operator can easily use these correlation to predict dephosphorisation levels depending on type of flux used and mode of addition.

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