Analysis on Deformation Law and Edge Damage of AZ31 Magnesium Alloy Sheet in Longitudinal Wave Rolling

Longitudinal wave rolling+flat roll rolling (LFR) is a new rolling process to reduce edge cracks and basal texture of magnesium alloy. This process can prepare magnesium alloy sheets with light edge cracks through one-pass longitudinal wave rolling+two-pass flat rolling. However, LFR process deformation law is obscure. In this research, the thermo- mechanical coupling finite element virtual rolling comparison and physical experiments of LFR and flat rolling+flat rolling (FFR) of AZ31 plate were conducted, and the metal deformation law in the longitudinal wave rolling deformation zone and its influence on the edge damage of the plate were analyzed. The results show that a special-shaped rolling area forms in the longitudinal wave rolling, which causes shear strain in different parts of the sheet. Furthermore, the temperature drop at the edge of the plate is avoided due to the plastic deformation heat generated by rapid metal flow, which is beneficial to improving the plasticity. The influence of shear strain and temperature promotes the formation of mixed microstructure of LFR sheet and reduces the damage of trough, effectively inhibiting the generation and development of edge crack of magnesium alloy sheet.