Preliminary Investigation of the Process Capabilities of Hydroforging

Abstract

Hydroforging is a hybrid forming operation whereby a thick tube is formed to a desired geometry by combining forging and hydroforming principles. Through this process hollow structures with high strength-to-weight ratio can be produced for applications in power transmission systems and other structural components that demands high strength-to-weight ratio. In this process, a thick tube is deformed by pressurized fluid contained within the tube using a multi-purpose punch assembly, which is also used to feed tube material into the die cavity. Fluid pressure inside the thick tube is developed by volume change governed by the movement of the punch assembly. In contrast to the conventional tube hydroforming (THF), the hydroforging process presented in this study does not require external supply of pressurized fluid to the deforming tube. To investigate the capability of hydroforging process, an experimental setup was developed and used to hydroforge various geometries. These geometries included hollow flanged vessels, hexagonal flanged parts, and hollow bevel and spur gears.

A cold forging process for producing thin-walled hollow balls from tube using a plastic insert

“…Thin-walled machine parts with a wall thickness lower than 2 mm can be formed from sheet metal plates [9] or thin-walled tubes. To this end, the hydroforming method is most often used, in which the process stability is ensured by high-pressure liquids [10]. An alternative to liquids is the use of flexible media [11,12], e.g., those made of elastomers.…”

Numerical Optimization of the Blank Dimensions in Tube Hydroforming Using Line-Search and Bisection Methods

“…Results showed that the precrash of the tube increased H(w min ) almost to the top of the dome (Figure 5b). Thickness (mm) w ∈ (w1; w1 + 1.25) w ∈ (w2; w2 + 2.00) 1 (precrash max 4 mm).…”

“…In fact, the current production process consists of a multiphase process that mainly consists in tube preforming, cutting, welding of the third branch and beads grinding. In order to enhance the product, the company chose to investigate the possibility of replacing the current manufacturing process with Tube Hydroforming (THF) [1]. In THF, a blank tube is placed in hollow dies that are shaped as the desired geometry of the part.…”

“…In the case of T-joint productions, a third punch (namely counter-punch) can sustain the tube during the expansion along the third branch to prevent the tube bursting. Pressure, punch strokes and counter-force curves are the most important process parameters for the part feasibility [1] since they influence the strain paths and gradients that can lead to wrinkle formation or necking and the subsequent bursting of the tube [3]. Moreover, the contact between tube and dies plays a significant role in the process.…”

“…Moreover, the whole blank undergoes plastic deformation, therefore the hardening increases the material mechanical properties [7,8]. Finally, the part weight and dimensional accuracy are enhanced [1,2,7]. For its characteristics, THF is suitable for aeronautic [9], automotive [10,11] and pipe fields, mono [12] and bilayered [13] ones, as in the production of tubular components for fluids delivery, aero-engine, engine cradles, anti-intrusion bars, radiator supports or nozzle production.…”