Research On The Control Of Magnesium Alloy Rolled Edge Cracking

Magnesium alloy is the lightest alloy material. Due to its low density and strength stiffness, Magnesium alloy is widely used in the aerospace, automotive, computer and other industries. Good mechanical properties of AZ31 B magnesium alloy sheet could not be got after rolling. The select of product specifications is narrow. It can not meet the requirements of all shapes and sizes. There are more serious defects in the organization. The yield is also low. So its application is limited only in some areas. Magnesium alloy can not as good as steel or aluminum alloy in plastic deformation. Because magnesium alloy has the hcp structure, influenced by the rolling conditions. Magnesium alloy sheet rolling process is more complex. Especially the magnesium alloy edge cracking problems is determined by temperature. Optimized rolling process will also be able to improve the degree of edge crack problem. The way to improve the edge crack problem is the main topic in this paper. By means of studying and improving the rolling process substrate to reduce edge cracking, then high yield will be got.Different rolling conditions were taken to roll AZ31 B magnesium alloy. Then the mechanical properties and microstructure properties could be analyzed after tensile test at room temperature. Determining good rolling process will provide a basis for further study of magnesium alloy rolled edge cracking problems.Multiple group alloy plates were taken on the criss-cross rolling process. Then edge cracks and mechanical properties would be comparative analysed. The research had shown that: the edge cracking could be improved by the criss-cross rolling. The same way as the slab anisotropy.Temperature is considered as the important factor for magnesium alloy rolling. The research had shown that: coated aluminum would reduce the drop, especially in the edge portion. At the same time it could inhibit edge cracks further expansion. Applying double insurance seeks to get a better magnesium alloy sheet.After pre-changing the shape of edge, the rolling of magnesium alloy sheet were simulated by DEFORM-3D software. Then observing the changes in temperature, and the rolling force and other factors, The main analysis was probability of the formation of edge cracks.In addition, the differences in microstructure and properties of magnesium alloy base will also affect the edge crack problem. So the magnesium alloy material was changed by adding rare earth elements. Then observing edge cracks generated case of rolled magnesium plate. The analysis whether earth elements improved the slab edge cracks was discussed. The research had shown that: the edge cracks could be ameliorated by adding rare earth elements. But it was not better to add excessively.The study relied on "Wide magnesium alloy sheet metal CNC rolling theory and technology research project" and "Wrought magnesium alloy sheet strip steckel isothermal rolling theory and technology research graduate technological innovation project". The error between experimental results and numerical simulation's results are small, this study has some significance on the project. It has some theoretical guidance to improve the magnesium alloy rolled sheet edge cracking problem.