Development of Segregation Etch Print Method and Its Application to Investigation of CC Slab Segregation

The segregation etch print (EP) method is a new method for detecting and recording segregation in low S and Ca added steels. This EP method can rapidly and conveniently detect segregation over a wide area with high resolving power. When EP was applied to CC slab, a coarse network structure was found in the equiaxed crystal zone, which could not be seen by the ordinary etching method for detecting the solidification structure. It was found that the fineness of the network structure was related to the segregation level and the fine structure remarkably suppressed not only central segregation but also V-shape segregation. Furthermore, the following casting conditions were considered to be important for making the network structure fine. 1) Low casting velocity 2) Low casting temperature 3) Strong spray cooling 4) Addition of REM 5) Reduced thickness of slab