EFFECT OF TIN SEGREGATION ON THE STRUCTUR E AND PROPERTIES OF CONTINUOUSLY CAST SLABS

The aim of the presented paper is a study of the effect of tin segrega tion on the structure, transition temperature of notch toughness, and fracture morphology of continuously cast slab of low carbon steel in d ependence on the mean tin concentration which was in range from 0.0065 to 0.134% Sn. The results indicate that at the high concentration of Sn (0.134%, 0.105%), there were significantly higher enrichments of th e skin with concentration peak measured, up to 0.42% to 0.45% Sn, in d epths up to 6 mm. This distance approximately corresponds to the onset of explicit oriented dendritic solidification. Deterioration of the t ransition temperatures in the surface skin, tested by impact testing o f notched specimens, is caused by the tin macrosegregation to the slab skin if compared to the results in the thickness center of the slab. Increasing the Sn content, an increase of intergranular facets was obs erved, implying the weakening of initial austenite grain due to micros egregation first of Sn, but also of the other present impurities.