Hydroforming

About: Hydroforming is a research topic. Over the lifetime, 2796 publications have been published within this topic receiving 26293 citations. The topic is also known as: Bulge forming.

Outflow Characteristics of a Pressure Medium during Sheet Hydroforming

Abstract: The outflow characteristics of a pressure medium during a sheet hydroforming process have been studied experimentally by directly measuring the hydraulic pressure distribution. Initial measurements of the outflow of the pressure medium though the gap between two clamped dies were carried out in order to verify the method for measuring the hydraulic pressure distribution employed in this study and to investigate the basic properties of the outflow. The upward forces were calculated by integrating the measured hydraulic pressure during the outflow and found to be in satisfactory balance with the clamping forces, which demonstrates the validity of this measurement method. Furthermore, we suggest that the critical outflow pressure can be predicted by considering the force equilibrium. An experimental investigation of a square-cup sheet-hydroforming process was then carried out. The upward forces were calculated by integrating the measured hydraulic pressure and again found to be in satisfactory balance with the forming forces at the beginning of the process, which shows that the critical outflow pressure can also be predicted for square-cup deep-drawing processes. The hydraulic pressure distributions in the flange area and the chamber change significantly as the sheet conforms to the die shoulder, and the friction loss of hydraulic pressure at the die shoulder becomes large. These results indicate that the magnitude of the fluid-lubrication effect on the drawability of the sheet can vary with the stage of sheet deformation.

Prediction of forming limit diagrams using the modified M-K method in hydroforming of aluminum tubes

Abstract: The purpose of this study is to predict forming limit diagrams (FLDs) for AA6063 and AA6065 aluminum seamless extruded tubes. The Modified Marciniak and Kuczynski (M-K) method is used with Barlat’s 1989 anisotropic yield function and Voce equation. Furthermore, a new calibration method for FLD determination based on the modified M-K method is also applied. The predicted forming limits correlate well with experimental data. It is shown that in comparison to other methods, this method is able to predict necking in tube hydroforming with more accuracy. Therefore, this method can be used to predict bursting in a wide range of practical tube hydroforming of aluminum alloys.

New die design for improvement of die corner filling in hydroforming of cylindrical stepped tubes

Abstract: Seamless tubular components, such as stepped tubes, conical tubes, and box shape tubes, are produced mainly in the tube hydroforming process. In forming the components in this process, complete filling of the die corners and obtaining a sharp corner is very difficult or even impossible. In this paper, the die corner filling in hydroforming of cylindrical stepped tubes was improved by a new die set. The proposed die was simulated and the filling of the die cavity was investigated. In order to verify the simulation results, the new die set was manufactured and some experiments were performed. It is shown that by using the new die set the parts with sharp corners and with more uniform thickness distribution could be produced. The simplicity of the die and low internal pressure are further advantages.