Experimental and Numerical Studies of Deep Drawing and Redrawing of 304 Stainless Steel Sheet

Abstract

The drawability of sheet material in deep drawing followed by redrawing has not been studied theoretically in detail. The clamping force during deep drawing has not been properly simulated by FE method in the past due to the neglect of the operating machine stiffness. In addition, deep drawing process with centre hole blank has not been investigated in detail experimentally and numerically in the previous work. All of these aspects are studied in this work. A new FE model for deep drawing and redrawing has been developed, which accounts for the operating machine stiffness. In this model, the draw die is connected to a semi-rigid component of the test frame by some spring elements so that the stiffness of the operating machine can be controlled by the stiffness of these springs. Also, a mathematical model to determine the limiting drawing ratio (LDR) of deep drawing and redrawing processes has been derived based on the extension of an existing analytical model and Hill's anisotropic criterion. The results of the mathematical model have been validated by corresponding experimental and FE simulation work in terms of punch load and clamping force versus punch displacement and thickness distributions along the product profile. Furthermore, deep drawing with centre hole blank has been studied in terms of flanging ratio and the results of FE simulation are in good agreement with experimental work.