Comparative study of warm and hydromechanical deep drawing for low-carbon steel

Abstract

Deep drawing is a process of converting sheets into cup-like-shaped components. It is a complex process, and process parameters play an important role. In this paper, two deep drawing processes namely warm deep drawing and hydromechanical deep drawing are compared. A 20-t hydraulic press is used to draw the cups. To ensure drawing at a fixed temperature in warm forming, heaters are connected to the lower die. Experimental results are compared with finite element simulations. Coefficient of friction in simulation is calculated by inverse analysis of comparing the load displacement curves. In hydromechanical deep drawing, the process is assisted by a hydraulic counter pressure. The peak load obtained in hydromechanical deep drawing has been found to be significantly higher than the peak load in both warm and conventional deep drawing and is influenced by the clearance between punch and die and the maximum counter pressure in the fluid chamber. Limiting draw ratio (LDR), von Mises stresses, and thickness distribution in the drawn cups by varying the temperature of the blank in case of warm forming and varying the pressure in case of hydromechanical deep drawing are studied using experiments and finite element simulation.