Beneficial effect of low plastic deformation rate on the flatness and residual stress of the magnesium alloy plate straightened at room temperature

Currently, magnesium alloys are extensively used owing to their excellent comprehensive mechanical properties. Rolling is a primary method used to produce magnesium alloy plates. However, so far, only few reports have been investigated about the straightening of rolled magnesium alloy plates. In this study, multi-roller straightening of the magnesium alloy plate is theoretically analyzed and simulated using the finite element method. Multi-roller straightening process of the magnesium alloy plate was performed as follows: the original bending curvature that exhibited large numerical differences in different directions was gradually reduced through reasonable distribution of the plastic deformation rate of each straightening roller system. Finite element simulation and experimental results are obtained for room-temperature magnesium alloy plate straightening at four different plastic deformation rates. However, the straightening effect is minimal when the micro plastic deformation rate is used for straightening the magnesium alloy plate with an initial curvature, this is because the reverse bending rate required for straightening is not attained. Straightening effect can be achieved with low, moderate, or high plastic deformation rates, and the flatness achieved after straightening at a low plastic deformation rate is relatively better than that obtained using moderate and high deformation rates. Both perpendicular to and along the straightening direction, the residual stress after straightening is less than that observed before straightening. Furthermore, the residual stress after straightening at a low plastic deformation rate is the lowest and uniformly distributed.