---

Aluminum alloys have high strength to weight ratio and Poor formability at room temperature is the main drawback of using these alloys. In order to overcome this limitation, the work material is formed at higher temperature. One of the forming processes is hydrodynamic deep drawing on which no relevant research has been reported in warm condition. In the present paper, after examining the formability of 5052 aluminum alloy in warm hydrodynamic deep drawing, the effect of media pressure, temperature and forming speed on thickness distribution and punch force in forming of flat-bottom cylindrical cups was investigated. In order to perform a complete investigation, the simulation of the process was established using ABAQUS software. It was illustrated that the results was in accordance with the experimental findings. It was also demonstrated that increasing the maximum oil pressure to a specified level could improve the thickness distribution and lead to increasing the punch force. The required punch force was decreased with increase in temperature but remained unchanged by punch speed variation. The maximum thickness reduction was decreased with increasing and decreasing of temperature and punch speed, respectively. Moreover, the forming of the sheet at room temperature, isothermal and non-isothermal warm forming processes was compared. It was concluded that the maximum thickness reduction in the formed part was less in the cases of cold forming and non-isothermal warm forming than the isothermal warm forming. But the required forming force is decreased in isothermal warm forming when compared with the other two conditions.

---

Production of double-stepped metal sheet parts is considered as a complex and difficult task in industries. The crankcase is such a complex double-stepped part for the automobile industry, which its production with traditional methods is associated with many problems. In this paper, the formability of this stepped part has been studied experimentally and by simulation using hydrodynamic deep-drawing with radial pressure. It is shown that the crankcase can be formed successfully in one step by the hydroforming process. Moreover, the effect of fluid pressure on the thickness distribution and die filling and the effect of geometric parameters such as punch corner radius and the height of the steps on the thinning, and also optimal shape design of the original blank were investigated. The study showed that choosing the correct forming pressure can improve formability and increase the amount of die filling. It is also illustrated that by increasing the punch corner radius, the maximum thinning is reduced and the thickness distribution is improved and by increasing the height of the steps, thinning in the wall of the first step and the punch corner radius increase and by decreasing the height of the steps, thinning position will be shifted toward the second step. Also, by optimizing the original blank, it has been concluded that the optimization of the shape of original blank has a major impact on the material flow and will delay the sheet rupture.

---

Prediction and prevention of wrinkling are very important in tool design and determining the effective parameters in sheet metal forming processes. In forming metallic cups, wrinkling generally occurs in the two regions of flange and wall. The control of wrinkling in flange area is not so difficult by controlling the blankholder pressure, but it is difficult in the wall region because the sheet is not supported in this area. In this paper, using a geometric method based on numerical simulation, the wrinkling in the wall of the symmetric conical parts in the developed hydrodynamic deep drawing with radial pressure and inward flowing liquid is investigated. In the process, two independent pressure supplies have been used for forming the sheets. Due to the nature of the process, the effects of radial and cavity pressures on wrinkling have been investigated. In addition, the effects of material, initial blank thickness and punch velocity on wrinkling in wall area were investigated. To verify the results of the simulation, several experimental tests have been done on the St13 and copper sheets. Good agreement between the simulation and experimental results shows the reliability of this method in the wrinkling study. It was also demonstrated that increasing the maximum radial pressure or decreasing cavity pressure leads to increasing wrinkling. Additionally, wrinkling was decreased with increasing blank thickness. Moreover, it was shown that wrinkling simulation is much depended on input parameters such as punch velocity and appropriate element size