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.

Design, Fabrication, and Experimental Validation of a Warm Hydroforming Test System

Abstract: In this study, a hydroforming system was designed, built, and experimentally validated to perform lab-scale warm hydromechanical deep drawing (WHDD) tests and small-scale industrial production with all necessary heating, cooling, control and sealing systems This manuscript describes the detailed design and fabrication stages of a warm hydroforming test and production system for the first time In addition, performance of each subsystem is validated through repeated production and/or test runs as well as through part quality measurements The sealing at high temperatures, the proper insulation and isolation of the press frame from the tooling and synchronized control had to be overcome Furthermore, in the designed system, the flange area can be heated up to 400 °C using induction heaters in the die and blank holders (BH), whereas the punch can be cooled down to temperatures of around 10 °C Validation and performance tests were performed to characterize the capacity and limits of the system As a result of these tests, the fluid pressure, the blank holder force (BHF), the punch position and speed were fine-tuned independent of each other and the desired temperature distribution on the sheet metal was obtained by the heating and cooling systems Thus, an expanded optimal process window was obtained to enable all or either of increased production/test speed, reduced energy usage and time Consequently, this study is expected to provide other researchers and manufacturers with a set of design and process guidelines to develop similar systems

Hydroforming Process for an Ultrasmall Bending Radius Elbow

Abstract: Bent pipes are widely used in automotive, aviation, and aerospace industries for delivering fluids. Parts having small relative bending radiuses are called elbows. However, fabricating a thin-walled elbow part using the simple bending process poses many challenges. One possible way to manufacture elbows is with the stamping-welding process. The major drawbacks of this method include the decline in sealing performance and the addition in weight attributed to the lap welding process. Tube hydroforming (THF) is considered as a feasible solution to these problems. However, the forming process could be quite complex, and multistep forming is necessary. This study investigates the effects of preliminary processes on elbow forming such as bending, partition forming, and heat treatment and presents a high-performance optimized process design to achieve an ultrasmall radius elbow. The effects of multistep forming on the thickness distribution and the heat treatment on the microstructure have been evaluated. The results obtained from simulations show a reasonable agreement with those from the experiments.

Experimental Study of Steam Hydroforming of Aluminum Sheet Metal

Abstract: This work presents an experimental study of aluminum sheet forming. A steam hydroforming process that takes advantage of the coupling between the thermal and mechanical loads applied to the sheet metal is introduced. The results confirm the feasibility of the forming process. The effects of variation of the supplied electrical power on the hydroforming temperature and steam pressure are studied. In addition, the evolution of strains and stresses in metal sheets are analyzed. The experimental results show that the supplied electrical power increases the heating rate and has no effect bursting temperature or pressure. Moreover, the evolution of the vapor pressure as a function of temperature is independent from the supplied electrical power and the deformation in the thin sheets under the steam pressure decreases the stress flow and raises the plastic deformation.

Formability of advanced high strength steel tubes in tube bending and hydroforming

Abstract: An investigation of the tube hydroforming process is conducted in order to understand the effect of prebending operation on formability in tube hydroforming and assess the application of the newly developed Extended Stress-Based Forming Limit Curve (XSFLC) method to the prediction of failure in tube hydroforming. Two sets of experiments on straight tube hydroforming and pre-bent tube hydroforming were conducted on tubes manufactured from three steel grades, namely DDQ, HSLA350 and DP600, which represent mild steel, high strength steel and advanced high strength steel, respectively. All tubes had the same outer diameter of 76.2 mm and the same nominal wall thickness of 1.8 mm, which enabled direct assessment of the effect of material strength on formability in tube hydroforming. For pre-bent tube hydroforming the tubes were bent to 90 degrees before hydroforming. The effect of the increased axial compressive load, termed the end-feed load, on tube formability in hydroforming was investigated. All experiments were simulated using the explicit dynamic finite element code LS-DYNA in order to investigate the accuracy of numerical predictions in the tube hydroforming process. The numerical simulations, validated using the experimental data, were then utilized to investigate the prediction of necking in straight and pre-bent tube hydroforming using the XSFLC method. The formability, burst pressure and corner-fill expansion in hydroforming of the pre-bent tubes was considerably less than that exhibited in hydroforming of the straight tubes. In both straight and pre-bent tube hydroforming, the application of the end-feed load postponed failure and significantly increased internal pressure and corner-fill expansion at burst. The finite element models accurately predicted the results of the tube bending and tube hydroforming experiments. The straight tube hydroforming simulations, validated using the experimental results, enabled accurate prediction of the failure location and tube internal pressure at the onset of necking using the XSFLC method. In order to obtain the XSFLC for each alloy, strain-based FLCs were calibrated using the results of tube free expansion tests. The results of the tube free expansion tests and corresponding numerical simulations also served to validate the tube material properties for the FE models. Straight tube hydroforming simulations were utilized to investigate the effect of friction between the tube and the die on the hydroforming process parameters and necking predictions using the XSFLC method. The validated pre-bent tube hydroforming simulations captured the trends in the increase of tube internal pressure at the onset of necking with the increase of end-feed load using the XSFLC method.

Welded steel pipe having excellent hydroforming property and production method therefor

Abstract: PURPOSE: Provided are a welded steel pipe which has excellent hydroforming properties, and its production method. CONSTITUTION: A welded steel pipe comprises, by mass, 0.05 to 0.2% of C, 0.2% or less of Si, 1.5% or less of Mn and 0.01% or less of S, 0.1% or less of P, 0.1% or less of Al, 0.01% or less of N, and the balance of Fe and impurities. Thus, the welded steel pipe having a tensile strength of 400 MPa or more, n x r of 0.22 or more and excellent hydroforming properties is obtained.