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.

Method of manufacturing a vehicle frame component by high velocity hydroforming

Abstract: A method for high velocity hydroforming a vehicle frame member including providing a hollow tubular member (30) and a die having an internal die cavity (28). The tubular member is positioned within the die cavity and filled with a fluid. A shock wave is created within the fluid, thereby causing hyperplastic forming of the tubular member to expand it outwardly into conformance with the shape of the die cavity. The shock wave can be created by discharging an electric arc between a pair of electrodes (46) submerged within the fluid. The ends (32) of the tubular member can be fed into the die cavity during expansion to provide for a relatively uniform wall thickness in the deformed tubular member.

“Size effect” related hydroforming characteristics of thin-walled 316-L bellow considering pressure change

Abstract: Due to the complicated deformation characteristics of thin-walled bellows with different specifications and its sensitivity to forming parameters in hydroforming (mainly referring to internal pressure), the process may encounter defects, i.e., overthinning, cracking, and wrinkling. To avoid defects and achieve products with high quality, it is a challenge to carry out reliable evaluation of the deformation behaviors of thin-walled bellows induced by the “size effect” with considering the inevitable fluctuation of pressure. In the paper, the hydroforming characteristics (including wall thinning degree and springback) of thin-walled 316-L bellows induced by geometry factors such as inner diameter, wall thickness, convolution width, and convolution height are clarified using finite element (FE) simulations. Meanwhile, deformation characteristics of the bellow considering pressure change are discussed. The numerical simulation results illustrated that the wall thinning degree and springback values of bellows are significantly affected by size factors, and are sensitive to pressure change when decreasing initial wall thickness and increasing convolution height. The results provide a better understanding of the process and a guideline to realize precision forming.

Experimental and numerical study on formability in tube bulging: A comparison between hydroforming and rubber pad forming

Abstract: Flexible-die forming methods such as hydroforming (HF) and rubber pad forming (RPF) allow producing a variety of complex tubular components that are difficult to fabricate by means of conventional forming. In this paper, firstly, in the bulging of a tube with oil pressure using numerical approach, weld-seam was modeled as a mechanical defect and non-homogeneity factor was calibrated by experimental observations and Vickers micro-hardness testing. Forming limit diagram (FLD), as well as effective plastic displacement factor, was utilized to estimate the initiation and evolution of damage, respectively. Then, with the aim of achieving a defect-free part in RPF process, the effect of lubricating conditions was experimentally and numerically examined. The sound parts were obtained using nylon and drawing oil, respectively, at the tube/rubber and the tube/die interaction surfaces. The results represented that by utilizing the accurate non-homogeneity factor, the numerical method can closely predict the...

Springback and compensation of bending for hydroforming of advanced high-strength steel welded tubes

Abstract: Bending springback plays an important role in hydroforming of curved hollow components, and the effect will be more apparent with the increase of the strength of the material. In order to predict and eliminate the effect of springback on hydroforming process, springback of DP590 welded tube was investigated in computer numerical control (CNC) bending process using theoretical analysis, numerical simulation, and experimental methods. The effects of the bending angles, the diameter-thickness ratio d/t, and the relative bending radius R/d on springback are studied, and the influence factor of the weld position is considered. The theoretical and experimental results show that the springback of the DP590 welded tube with 65 mm in diameter and 2.6 mm in thickness varies within the range from 4.0 to 4.9 % and the amount of springback is influenced by the tube diameter and thickness. The springback reduces from 7.0 to 3.5 % when the diameter-thickness ratio is increasing from 10 to 40. On the contrary, the springback increases from 3.7 to 7.2 % when the relative bending radius is increasing from 1.2 to 4.0. The effect of weld position on springback is very little, but it has a negative effect on defects of hydroforming and wall thickness distribution. It is liable to crack when hydroforming if the weld locates on the outside or neutral layer of the bend. Finally, springback rules and weld effect are applied to form a control arm. A sound part had been successfully manufactured to avoid flash and crack defects considering the appropriate springback compensation and weld position.