Influence of undercooled surface of CCSP on core distribution of longitudinal and transversal stresses during hot rolling

Investigation of causes of cracking in the interior of thick rolled products. First part of the study concerns research into possible causes of cracking with respect to termal conditions of rolling and microstructural features of steel. Examination of microstructure revealed casting cracks on prior austenite grain boundaries, which might initiate formation of the critical cracks. Second part of paper contains FormFEM and Forge2005 program simulation-aided feasibility study of enhancing the amount of reduction in the bloom centre by means of bloom surface undercooling. Comparison of common rolling process and the newly-designed process is provided. Primary attention has been paid to the magnitude (and sign) of the longitudinal and tansversal stresses in the bloom cross-section and to penetration of strain into the bloom centre.