| A finite element model has been developed to analyze the bulging near the straightening zone, produced by elasto-plastic mechanism. The analysis leads to the following conclusions. 1) The bulging deformation can cause internal cracks in the withdrawal direction or in the width direction at the solidification front of the solid shell. 2) The tensile strain at the solidification front, resulting from the bulging deformation, increases with increasing roll spacing and with decreasing solid shell thickness. 3) The roll spacing is of primary concern, compared with solid shell thickness, in that irrespective of solid shell thickness, the bulging strain can hardly reach the critical strain when the roll spacing is small. 4) Even a small misalignment can lead to a remarkable increase of bulging strain by free bulging. 5) In spite of the ambiguity in the assumption of the temperature distribution in the solid shell and the temperature dependence of material properties, the results are in qualitative agreement with the experimental ones. |
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