On Mechanism of Formation of Negative Segregation Zone (alias ‘Settling Crystal Zone’) in Large Steel Ingot and Origin of (Macroscopic Oxide) Inclusions Appeared in This Zone

Abstract

In order to investigate the mechanism of formation of negative segregated zone inside large steel ingots and the origin of macroscopic-oxide inclusions appeared in this zone, a series of experiments on which 3 t sand steel ingots were used was studied.
As a result, it was presumed that their formations are due to the following three points:
i) The decrease of effective distribution coefficient connected with the delay of solidification.
ii) The solidification over wide extent in negative segregated zone.
iii) The floatation of concentrated molten steel.