To prevent the excessive fastening of a spindle, to absorb the expansion of the spindle and further, to prevent the crack of a stopper head by inserting a fixed quantity of combustible material into a female screw hole for spindle of the stopper head.
The thickness of mortar 4 and the screwing position of the spindle 3 become the fix by inserting the fixed wt. of the combustible material 2 into the female screw hole for spindle of the stopper head 1, and at the time of preheating, the combustible material 2 is burnt to develop a gap. The expansion of the spindle is absorbed and the crack of the stopper head is prevented by arranging the fixed quantity of this gap. Further, even in case of using this stopper head in a tundish, the crack, erosion in the joint part, etc., are not developed and good operation can be executed.
TOMIMATSU HIROYASU
OKUMURA TOMOHIRO
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