LAUSR

Abstract In order to reveal the formation mechanism of microstructural delamination in flange steel during punching, the microstructural characteristics of flange steels with 0.064, 0.085, and 0.101 wt% carbon contents were analyzed by an optical microscope, optical emission spectrometer, metal in situ analyzer, and electron probe microanalyzer. It was found that microstructural delamination occurred due to C and Mn segregation, especially the former. The intensive segregation degree of C was dependent on its relatively smaller partition coefficient. Moreover, the segregation degree gradually decreased with the decreasing carbon content. And the increased segregations of elements except carbon were related to the coupling effect between different alloying elements. Furthermore, C and Mn were prone to segregate at the 1/4th position along the transverse direction of the casting slab; hence, almost no segregation was noticed at the edge of the casting slab. The homogenization treatment had a substantial effect on the elimination of C segregation; however, Mn segregation was relatively hard to be removed. Graphic Abstract