Investigation of Punch Shape and Loading Path Design in Hydro-Flanging Processes of Aluminum Alloy Tubes

Abstract

Hydro-joining is composed of hydro-piercing, hole flanging and nut-inlaying processes. In this study, a new hydro-flanging process combining hydro-piercing and hydro-flanging is proposed. An internal pressured fluid is used as the supporting medium instead of a rigid die. Three kinds of punch head shapes are designed to explore the thickness distribution of the flanged tube and the fluid leakage effects between the punch head and the flanged tube in the hydro-flanging process. A finite element code DEFORM 3D is used to simulate the tube material deformation behavior and to investigate the formability of the hydro-flanging processes of aluminum alloy tubes. The effects of various forming parameters, such as punch shapes, internal pressure, die hole diameter, etc., on the hydro-flanged tube thickness distributions are discussed. Hydro-flanging experiments are also carried out. The die hole radius is designed to make the maximum internal forming pressure needed smaller than 70 MPa, so that a general hydraulic power unit can be used to implement the proposed hole flanging experiments. The flanged thickness distributions are compared with simulation results to verify the validity of the proposed models and the designed punch head shapes.

An Analytic Solution for an Expanding/Contracting Strain-Hardening Viscoplastic Hollow Cylinder at Large Strains and Its Application to Tube Hydroforming Design

“…It is seen from this figure that the effect of ν on the pressure is most significant if ν is small enough. It is worth noting that ν decreases as U increases, as follows from Equation (21). Therefore, the behavior of the curves in Figure 1 is in agreement with physical expectations.…”

“…Recent reviews on this technology are provided in [18,19]. Despite the wide use of numerical methods for hydroforming process designs [20,21], simple semi-analytic solutions are essential for estimating the optimal values of the process parameters [22,23]. In particular, it has been shown in [24] that a simple plane-strain solution for the expansion of a two-layer tube supplies an accurate prediction for the maximum internal pressure value.…”

Latest Hydroforming Technology of Metallic Tubes and Sheets

“…The contributions are generally divided into three basic groups according to the workpiece geometry and forming methods. The first group is tube hydroforming (THF) [1][2][3][4][5][6][7][8][9], in which a hydraulic media and dies are used to deform a tube workpiece. The second group is tube forming [10][11][12][13][14], in which only dies are used to deform a tube workpiece.…”

“…Hwang and Tsai [4] developed a tube hydroforming process using a novel movable die design for decreasing the internal pressure to manufacture irregular bellows with small corner radii and sharp angles. Hwang et al [5] proposed a new hydro-flanging process combining hydro-piercing and hydro-flanging to investigate the effects of punch shape and loading path in the hydro-flanging processes of aluminum alloy tubes. Bach et al [6] used the functionality of the tools and the heating strategy for a curved component as well as a measurement technology to investigate the heat distribution in a component during hot metal gas forming (HMGF).…”

“…Recently, tube hydroforming processes sometimes incorporate piercing, flanging, or joining processes to become hydro-piercing, hydroflanging, or hydro-joining, which are more efficient compared with a single process and can reduce the total weight of the final product. Hwang et al [5] proposed a new hydro-flanging process combining hydropiercing and hydro-flanging to investigate the effects of punch shape and loading path in hydro-flanging processes of aluminum alloy tubes. Three kinds of punch head shapes were designed to explore the thickness distribution of the flanged tube and the fluid leakage effects between the punch head and the flanged tube in the hydro-flanging process.…”