Hot Deep Drawing Property of Electromagnetic Field and Ultrasonic Field Cast-Rolling AZ31B Mg Alloy Sheets

AZ31B Mg alloy sheets with thickness of 5 mm deformed by general cast-rolling and by electromagnetic field and ultrasonic field cast-rolling, were rolled by multi-passes to get the sheets with thickness of 1.3 mm. The microstructure and textures of two kinds of ultimate sheets were comparatively analyzed. Furthermore, deep drawing test for Mg alloy ultimate sheets was carried out in a temperature range between 175 ℃ and 300 ℃. Effect of forming temperature on deep hot deep drawing properties of two kinds of sheets was investigated. Results show that the average grain diameter of Mg ultimate sheet cast-rolled in electromagnetic field and ultrasonic field was 10-12 μm, while that of general Mg ultimate sheet was 14-16 μm. In contrast to general cast-rolling Mg ultimate sheet, basal plane texture of electromagnetic field and ultrasonic field cast-rolling Mg ultimate sheet had a lower orientational density, but the conical plane texture and cylinder plane texture of that had higher orientational densities. Hot deep drawing property of electromagnetic field and ultrasonic field cast-rolling Mg ultimate sheet with the maximum limiting drawing ratio of 2.0 at 250 ℃ was superior to that of general cast-rolling Mg ultimate sheet with the maximum limiting drawing ration of 1.875 at 250 ℃ in a temperature range between 175 ℃ and 300 ℃.