Mechanism of initiation Hot Tears in continuous casting blooms and appearing cracks on the surface of final product after rolling

The mechanism for initiation of Segregation Hot Tears have been investigated in this study. Also density of Hot Tear defects from surface to the centre of blooms produced by continuous casting and possibility of moving Hot tears towards surface during production of final products have been studied. Two industrial steel samples have been chosen for Metallographic and Electron mmicroscopic studies. The results show Segregation Hot Tears first appears as spheral particles of Mn-sulfide or as longitudinal cracks full of Fe with high concentration of Mn and S, but after that with the effect of stress, open hot cracks forms around spheral particles of Mn-sulfide. As the density of Hot Tear defects become more towards the surface, during final production process these defects reach the surface which deteriorate surface.