Abstract: Theoretical Forming Limit Diagram (FLD) available has too much error, and experimental FLD determination is quite difficult, neither could be applied to production easily. To solve this problem, on the basis of theoretical analysis, a new method to determine the FLD is given. Experiment indicates that the result is almost the same as the expert mental FLD, at the same time, experimental work is much decreased.

Key words: 板材, 成形极限图, 分散性失稳, 集中性失稳, 胀形