Effect of variable thickness cross rolling on edge crack and microstructure gradient of AZ31 magnesium alloy

The hot rolling experiment of AZ31 magnesium alloy was carried out by laying anoverlay mold at the initial temperature of 400 °C. According to the Mizushima automatic plan view pattern control system (MAS) rolling theory and the cross rolling process, different reductions in the middle and edges of the magnesium alloy were realized, and the influence of the regional controlled reduction rolling on the edge cracks and microstructure gradient of the magnesium alloy were analyzed. It is shown that this rolling approach has reduced the maximum edge crack depth of the rolled piece by 56.85%, and there is a weakening tendency in the base surface texture of the strip edge, the base surface texture density drops from 23.97 to 17.48 after ordinary flat rolling. It exhibits basal texture gradients from the edge to the middle of the sheet along the RD direction, which reflected the uneven deformation of the sheets. It is suitable for the processing of metal molds that require large edge reductions such as mobile phone shells, and provided a theoretical basis for the variable thickness rolling of the magnesium alloy strip.