Characterization of the Formation, Propagation, and Recovery of Sticker/Hanger Type Breakouts

Abstract

A non-standard, horizontal water passage mold has been used to investigate the initiation, propagation, and recovery of sticker and hanger type breakouts. The velocity of propagation of the hot spot in the shell down the mold has been measured to be 0.5 times the casting speed. The causes for sticker breakouts have been identified as casting too fast, changing cast speed or liquid level too rapidly, and/or insufficient lubrication between the mold and solidifying shell. Sticker or hanger breakouts have been shown to initiate virtually at the meniscus in all cases. The variation in instantaneous mold heat transfer rate and mold wall temperature profiles have been shown to be effective to predict sticker or hanger breakouts; the time variation of both mold friction and overall mold heat transfer rate has been shown to be ineffective in detecting sticker or hanger breakouts. The experimental observations have led to a theoretical hypothesis for the mechanism of initiation of the sticker and propagation of the hot spot in the sticker breakout. The events occurring during and after the initiation of sticker type breakouts followed by their recovery before spillage of liquid steel have also been characterized.