Influence of pre-bulging on deformation and hardness of dual-phase steel cylindrical cup by hydrodynamic deep drawing process

To quantitatively analyze the influence of pre-bulging on deformation, taking the dual-phase steel cylindrical cup with flat bottom as example, the experiments and simulation of the hydrodynamic deep drawing process with and without pre-bulging were carried out, and the equivalent effective strain distributions, wall thickness distributions and hardness distribution were discussed in details. The results indicate that the pre-bulging increases the thickness thinning, hardness and equivalent effective strain of the bottom. Compared with hydrodynamic deep drawing, when the relative pre-bulging height is 20%, the difference of equivalent strain decreases 16.7%, and the hardness of the bottom increases 23.8%.