Improvement on Magnesium Alloy Sheet Forming at Warm Temperatures by Computer Simulation and Experiment

A proper forming temperature range was determined, and the effects of blank holding forces on the workpiece quality were analyzed by warm deep drawing of cups in magnesium alloy sheets. The conditions of process defects as flange wrinkling and ruptures were analyzed by computer simulation with explicit finite element method to optimize the process parameters. Therefore, appropriate process parameters were selected to avoid forming defects effectively. In the paper, a rigid blank holder was used to adjust blank holding forces. A special liquid lubricant PTFE was used on the tool surfaces. Efforts were made to optimize process parameters by analyzing the causes of defects in order to improve the Limit Drawing Ratio of magnesium alloy workpieces. It is found that rolled magnesium alloy sheets are of good deep drawing formability at a forming temperature range of 105–170°C with the higher Limit Drawing Ratio up to 2.44. It is also necessary to control the time of heating blanks. The formability will be reduced severely by excessive heating time.