Experimental Analysis on the Causes of the Breakout of Continuous Cast Steel Slab

Experimental Analysis on the Causes of the Breakout of Continuous Cast Steel Slab

Článek WoS

The paper deals with investigation into segregation behavior of selected elements in longitudinal cut of continuous steel slab, in the breakout area. The breakout occurred after a flying change of tundish in order to begin casting of another steel grade. Altogether 11 samples were taken from the part of a solidified slab. Concentrations of selected elements (Al, Si, P, S, Cr, Mn, Ni and Mo) were measured in these samples using scanning electron microscope and energy dispersive spectroscopy. Using the original mathematical models the basic micro segregation characteristics and the parameter of macro-heterogeneity were further determined for each analyzed element. Then a quantitative measurement of inclusions ("micro purity") in the samples was performed using a metallographic microscope. Then method of differential thermal analysis was used for the measurements of temperatures of phase transformations. The following main results were found: Magnitude of micro segregation of the analyzed elements in the measured sections of 1000 mikrom is approximately the same in all the analyzed samples.Chemical macro heterogeneity is very high across the analyzed slab section.Very uneven mixing of melts of both steels was probably one of the main causes of formation of the breakout.

The paper deals with investigation into segregation behavior of selected elements in longitudinal cut of continuous steel slab, in the breakout area. The breakout occurred after a flying change of tundish in order to begin casting of another steel grade. Altogether 11 samples were taken from the part of a solidified slab. Concentrations of selected elements (Al, Si, P, S, Cr, Mn, Ni and Mo) were measured in these samples using scanning electron microscope and energy dispersive spectroscopy. Using the original mathematical models the basic micro segregation characteristics and the parameter of macro-heterogeneity were further determined for each analyzed element. Then a quantitative measurement of inclusions ("micro purity") in the samples was performed using a metallographic microscope. Then method of differential thermal analysis was used for the measurements of temperatures of phase transformations. The following main results were found: Magnitude of micro segregation of the analyzed elements in the measured sections of 1000 mikrom is approximately the same in all the analyzed samples.Chemical macro heterogeneity is very high across the analyzed slab section.Very uneven mixing of melts of both steels was probably one of the main causes of formation of the breakout.

micro-segregation, continuously cast slab, steel, breakout, intermixing

micro-segregation, continuously cast slab, steel, breakout, intermixing

KAVIČKA, F.; STRÁNSKÝ, K.; DOBROVSKÁ, J.; DOBROVSKÁ, V.; FRANCOVÁ, H.; SMETANA, B.

2015

09.04.2014

0255-5476

Materials Science Forum

782 (2014)

Apr/09

Švýcarská konfederace

67

72

6