Analysis of Atypical Breakout During Radial Continuous Casting of Slab in the Straightening Zone. III. Experimental Research on the Causes of the Breakout.

článek v časopise - ostatní, Jost

angličtina

The present paper is a detailed experimental study into an atypical breakout occurred during continuous casting of slab in the straightening zone. The paper deals with investigation into segregation behaviour of selected elements in longitudinal section of steel slab in the breakout area. The break 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 solidified slab. The samples were taken both from the breakout areas and from the areas not affected by the breakout. First the concentration of selected elements was measured in individual samples by spectrometry. Concentrations of selected elements were measured in these samples using scanning electron microscope and energy dispersive spectroscopy. Concentration data were measured in each sample at 101 points along the selected line of 1000 microm. Concentration data from the individual samples were then subjected to basic statistical analysis. Using the original mathematical models the basic micro segregation characteristic were further determined for each analysed element. The parameter of macro heterogeneity was also determined for individual elements from the measured concentration data. Furthermore a quantitative measurement of inclusions 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, namely the liquidus and solidus temperatures. The following main results were found: Magnitude of micro segregation of the analysed elements in the measured sections of 1000 microm is approximately the same in all the analysed sample. Chemical macro heterogeneity is very high across the analysed slab section.Elements with different concentration in the melts of the steels A and B are along the longitudinal axis distributed wery unevenly. Very uneven mixing of melts of both steels was probably one of the main causes of formation of the breakout

Breakout, steel slab, experimental measurement, chemical composition of steel, chemical macroheterogeneity, distribution curves, dendritic segrergation

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

2013

15. 11. 2013

0018-8069

Hutnické listy

2013

5

Česká republika

8

13

6