Breakouts during Continuous Casting of Liquid Steel Nov01

Breakouts during Continuous Casting of Liquid Steel...

Breakouts during Continuous Casting of Liquid Steel One of the worst catastrophic process failures that can occur during the process of continuous casting (CC) of liquid steel is the breakout of the liquid steel. Breakout occurs when solidifying strand steel shell ruptures or tears beneath the mould. There are several reasons due to which the solid shell of the strand breaks and allows the still liquid steel contained within it to spill out and damage the equipment of CC machine. A breakout is the most detrimental incident associated with the process of continuous casting. This incident is not only very costly but is also a serious safety hazard for the operators of the CC machine. Breakout leads to a shutdown of the strand and results in the loss of production time along with significant drop in the yield. Hence each breakout causes a significant direct economic loss. For the restoration of the CC machine strand, it typically requires an extended turnaround involving removal of the spilled steel material from within the strand equipment and/or replacement of the damaged part of the equipment. Breakouts can be avoided by reducing the casting speed thereby providing more residence time in the mould for the steel to solidify. To avoid the occurrence of a breakout, it is critical to detect improper solidification of the steel shell in advance with enough lead time to appropriately slow down the CC machine. A number of approaches have been adopted to predict breakouts in the continuous casting process. A breakout is normally due to the steel shell wall being too thin to support the liquid steel column above it. This is caused due to a condition which has several root causes often associated with the management of heat transfer. Improper cooling water...