Abstract
	Conti-casting embrittlement and surface cracking can occur during continuous casting in a wide interval of temperatures starting from the solidus temperature down to the temperature of 700 0C, what practically is the whole pass through the casting plant.
	In the described temperature interval a large number of changes and processes take place&. The primary crystallization and dendritic structure formation, the transformation of ? – ferrite to austenite, growth recrystallization processes and granulated granulated grains formation, the transformation of austenite to ferrite and the formation of the secondary micro structure. The mentioned changes are made more complex by the peritectic crystallization transformations and by segregation and precipitation processes. Frequently it is quite difficult to find the exact origin of embrittlement in such a complex system.
	The basic microstructure is analyzed in this contribution to get metallographic signs, accompanying surface defects in continuous casting. These signs are: segregation lines, carburization and decarbonization around the crack, ferrite bands and ferrite net patterns, coarse austenite grains, particles and impurities precipitated in grain boundaries. Valuable knowledge can be derived from the structural analysis, though sometimes they are not enough for the exact defect cause and locality definition if they are not confronted with the data and information about the production technology used and with the knowledge collected about the high temperature behavior of the given steel type.