Composite rolls are widely used in hot rolling mill because of the excellent hardness, wear resistance and high temperature properties. During hot rolling process, composite rolls are subjected to heating-cooling thermal cycles from the hot strip contact and water cooling. The thermal stress is added to already existing residual stress. The thermal fatigue cracking appears at roll surface, and the fracture is possible happen in roll centre when the tensile stress exceeds the centre strength. Therefore, residual stress plays an important role in composite roll. In this paper, FEM (finite element method) simulation is performed to investigate the generation mechanism of the residual stress during quenching process. It should be notedthat a large number of experimental data of the core and shell materials are utilized for the wide range oftemperature considering the quenching process. The results verify that initially the tensile stress appears on the roll surface but finally the compressive stress occurs.
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