The mathematic model of tension straightening process of magnesium alloy and experimental validation

The stress–strain curve of bending bar and the stress relax curve of AZ31 was obtained by a tension test using Gleeble-1500. The tension straightening process mainly consisted of the elastic loading-I and unloading stage, the elastic loading-II and unloading stage, and the elastic–plastic loading stage, which were based on the stretch force change during straightening. The circular bar straightening under one-dimensional bending was investigated and assumed to be linear strain-hardening elastic–plastic material. According to the elastic–plastic mechanics theory, the mathematical displacement–force model of a tension straightening process established, on which was based, the predicted displacement of tension straightening for various original deflection was calculated. The tension straightening experiment for AZ31 magnesium was conducted under the guidance of the predicted displacement. The experiment results present good straightness when there is a stress relaxation phenomenon or the temperature of tension straightening is 25 °C.