Continuous casting mould powders Jun16

Continuous casting mould powders...

Continuous casting mould powders Continuous casting (CC) mould powder is used primarily to facilitate the passage of steel through the mould. It is also known by names such as casting powder, mould powder and mould flux. CC mould powder plays an important role in the continuous casting of liquid steels. It is one of the most critical and influential factors for smooth continuous casting of the liquid steel. CC mould powder is sprayed at the top of the liquid steel in the mould either manually or by automatic feeders. CC mould powder after additions in the mould Heat up and loose some carbon by reaction with oxygen Forms a sintered layer Melts at a definite rate and forms sintered (mushy) and liquid layers. The liquid layer acts as a reservoir to supply liquid slag to the strand. This liquid pool should be deeper than the stroke length to ensure good lubrication. Forms a solid slag film through the first infiltration of liquid slag into the mould/strand gap. This slag film is glassy in nature and is typically 2 to 4 mm thick. This slag subsequently crystallizes in the high temperature regions adjacent to strand. Forms a liquid slag film typically of 0.1 mm thickness. This liquid slag is drawn down into the gap along the steel shell and lubricates the strand. This lubrication prevents the steel from adhering to the mould thus removing a cause of the strand break out. Schematic diagram of different layers of mould powder after its addition in the mould is given in Fig. 1 Fig 1 Schematic diagram of different layers of mould powder after its addition in the mould  Besides the function of mould lubrication, CC mould powder has to perform some more basic functions. These other basic...