ON THE BRICK INCLUSION TESTS BY USING A CoO TRACER

Abstract

The brick inclusions that presented in the 450kg ingots (killed, bottom pouring) are occurred by the erosion and fusion of the casting refractories. In this test, the authors investigated the degree of the brick inclusions occurred by the nozzle, the trumpet and the main runner bricks by use of a CoO tracer (not radio active). These three parts were considered the most important bricks concerning the brick inclusions from the. previous several investigations. The results were as follows:
(1) Assuming that scums occurred by erosion and fusion are mixed uniformly and float throughly in the mold, the floatability of these scums caused by nozzle, trumpet and main runner bricks during casting is indicated by the proportion 17:1:2 respectively. Calculated in terms of the unit length of these refractories, the floatability of scums correspond to the proportion 3.6:1.4:1 respctively.
(2) The proportion of the amount of scums which would not float is 1:110:39 respectively. These scums should be the cause of the brick inclusions.
With a view to decrease the brick inclusions in ingots, therefore, it will be advisable to improve mainly the quality of the trumpet bricks and the main runner bricks.