Residual Stress Simulation for Hot Strip Bimetallic Roll during Quenching

Bimetallic rolls are widely used in hot rolling mills because of excellent hardness, wear resistance, and high temperature properties. Considerable residual stresses are produced for the bimetallic roll during quenching. Moreover, severe thermal stresses are caused by heating‐cooling thermal cycles during subsequent hot rolling process. Fracture from the roll center may occur due to the residual stress adding to the thermal stress, and therefore, it is desirable to investigate the residual stress to improve roll service life. Therefore, FEM simulation of the bimetallic roll is performed for the quenching process. It should be noted that a large number of experimental data of the core and shell material are utilized for the wide range of temperature considering the quenching. The generation mechanism for the residual stress is discussed focusing on the effect of temperature gradient and phase transformation. Furthermore, the effects of shell–core ratio and diameter on residual stress are considered. Results show that the residual stress only slightly increases with increasing shell–core ratio, while significantly increases with increasing diameter. The residual stress is investigated for high speed steel bimetallic roll during quenching by FEM elastic‐plastic simulation. The optimum residual stress distribution is discussed to minimize the center tensile stress and to produce the surface compressive stress in the range of 200–500 MPa. Predicting the residual stress is realized by changing shell–core ratio, diameter, phase transformation, and material heat treatment process.