Exploring Liquid Impact Forming Technology of the Thin-Walled Tubes

2014 ◽  
Vol 633-634 ◽  
pp. 841-844 ◽  
Author(s):  
Cheng Ming Huang ◽  
Jian Wei Liu ◽  
Yin Zhong Zhong ◽  
Min Jian Wu ◽  
Kai Ming Wang ◽  
...  

In order to realize the objective of lightweight manufacturing, the forming methods of thin-walled tubes are studied in this paper. Liquid impact forming, a compound forming technique of thin-walled tube using stamping and hydroforming processes, is presented in order to reduce the forming difficulty and increase the forming efficiency. A simple experimental tooling, including stamping device and tube hydroforming apparatus is developed. Forming experiments of stamping and liquid impact forming processes in rectangular cross-section dies are performed for 304 stainless steel tubes. The results of experiments show that the liquid impact forming technology is feasible, and it will be widely applied in the future.

2019 ◽  
Vol 72 (5) ◽  
pp. 637-643
Author(s):  
Jianping Ma ◽  
Lianfa Yang ◽  
Yulin He ◽  
Jian Guo

Purpose This paper aims to study frictional characteristics of thin-walled tubes in the liquid impact forming (LIF) process. Design/methodology/approach LIF experiments under various impacting velocities were performed on SUS304 stainless steel tubes with various guiding lengths on a custom-designed measurement system to investigate the effects of impacting velocity and guiding length on the coefficient of friction (COF) in the guiding zone. Findings The results indicate that the COF changes dynamically in the guiding zone and decreases with the deformation process. The reduction range of the COF is wider in LIF than in both the conventional and pulsating hydroforming (THF), which may be contributed to the impacting velocities in a short time. Moreover, the COF decreases faster in the first half of the LIF process than in the second half. Under different impacting velocities and guiding lengths, the decreasing rate of the COF in the first half is more sensitive and obvious than that in the second half. Originality/value A method for determining the COF in the guiding zone in LIF is proposed and the frictional characteristics in LIF are studied. Comparing the COF of tubes in conventional THF, pulsating THF and the LIF process is valuable for improving and predicting the tubular formability in various hydraulic environments for industrial production. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2019-0269


Author(s):  
Taras Dovbush ◽  
Nadia Khomyk ◽  
Hanna Tson ◽  
Anatoliy Dovbush

Analytical and experimental investigations of the most loaded elements of the base frame of PRT-9 solid organic fertilizer spreader are carried out in this paper. The residual operation life of the central beam of the paired Z-shaped profile, as well as the lateral spars of the Z-shaped cross section are determined. According to the results of studies, it was found that the residual operation life of these system elements differ significantly. In order to achieve strength uniformity of the main frame elements, it is decided to weaken the central beam by replacing the paired Z-shaped profile with a thin-walled tube of rectangular cross-section and strengthen the lateral spars by replacing Z-shaped profile with a channel profile with the same height.


2021 ◽  
Author(s):  
Xiangwen Fan ◽  
Jianwei Liu ◽  
Zhu Xiao ◽  
Huiping Liang ◽  
Changying Sun ◽  
...  

Abstract Liquid Impact Forming (LIF) is a new composite forming technology based on Tube Hydroforming (THF) technology, which changes the volume of mould cavity through impact load and rapidly generates internal pressure to realize tube forming. It does not need external pressure supply source, and it is low cost and high efficiency. In order to study the forming characteristics of the natural bulging area of thin-walled metal tubes under different model side lengths and different model closing velocities, the change of the cavity volume of thin-walled metal tubes under impact hydraulic bulging was firstly analyzed theoretically, and a mathematical model of internal pressure was established. Then the effects of different loading parameters on the internal pressure, bulging height and wall thickness distribution in the natural bulging area of thin-walled metal tube were studied. Finally, through the comparison of finite element simulation analysis and experiment, it was found that the deviation between the experimental results and the numerical simulation was within 5%, which verified the accuracy and reliability of LIF. It also provides a certain theoretical research and application basis for the development of LIF of metal thin-walled tube.


Author(s):  
Guolin Hu ◽  
Chunrong Pan ◽  
Zheng Liu

Pulsating tube hydroforming with axial feeding is an effective method to improve the forming performance of thin-walled tube. A beneficial wrinkle can make the tube wall thickness more uniform and create a greater bulging height during forming process. The method of expressing the degree of wrinkle with geometrical and mechanical criteria is applied to distinguish the wrinkle types, and thus, the wrinkles can be divided into beneficial ones and harmful ones based on the deformation wrinkle features with different forming parameters. The wrinkling behavior in tube pulsating hydroforming with axial feeding was investigated in this article by experimental study, numerical simulation and theoretical analysis. The results showed that loading parameters had great influence on formability and wrinkling behaviors and that the beneficial wrinkles could be identified and used effectively by controlling the relation of wrinkling degree and forming parameters. Furthermore, the evolution processes of wrinkling behaviors in tube-bulging experiment were observed, the characteristics of wrinkling in every stage were analyzed and the relationship between wrinkling degree and forming parameters was established in the experiment.


Author(s):  
Y. L. Chen ◽  
J. R. Bradley

Considerable effort has been directed toward an improved understanding of the production of the strong and stiff ∼ 1-20 μm diameter pyrolytic carbon fibers of the type reported by Koyama and, more recently, by Tibbetts. These macroscopic fibers are produced when pyrolytic carbon filaments (∼ 0.1 μm or less in diameter) are thickened by deposition of carbon during thermal decomposition of hydrocarbon gases. Each such precursor filament normally lengthens in association with an attached catalyst particle. The subject of filamentous carbon formation and much of the work on characterization of the catalyst particles have been reviewed thoroughly by Baker and Harris. However, identification of the catalyst particles remains a problem of continuing interest. The purpose of this work was to characterize the microstructure of the pyrolytic carbon filaments and the catalyst particles formed inside stainless steel and plain carbon steel tubes. For the present study, natural gas (∼; 97 % methane) was passed through type 304 stainless steel and SAE 1020 plain carbon steel tubes at 1240°K.


Alloy Digest ◽  
1994 ◽  
Vol 43 (8) ◽  

Abstract NICROBRAZ 50 is a low-melting, free-flowing filter metal for honeycomb structures and thin-walled tube assemblies. It has low solubility. This datasheet provides information on composition, physical properties, and hardness. It also includes information on corrosion resistance as well as joining. Filing Code: Ni-460. Producer or source: Wall Colmonoy Corporation.


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1221
Author(s):  
Lu Bai ◽  
Jun Liu ◽  
Ziang Wang ◽  
Shuanggui Zou

In the field of cold bending, it is necessary to use ball mandrels, especially to bend thin-walled tubes with a small radius. However, the bending process with a ball mandrel is complex and expensive, and it is easy to jam the core ball inside the tube. To solve these issues, we designed two kinds of hollow non-ball mandrel schemes with low stiffness that were suitable for the small radius bending of thin-walled tubes. We evaluated the forming quality of cold bending numerically and the influence of the hollow section length and thickness on the forming indices. Our results showed that the thickness of the hollow section has a greater influence on forming quality than the length. As the hollow section’s thickness increased, the wrinkling rate first declined by approximately 40% and then increased by above 50%. When the thickness was 11 mm in scheme 1 and 13 mm in scheme 2, the wrinkling rate reached minimum values of 1.32% and 1.50%, respectively. As the hollow section’s thickness increased, the flattening rate decreased by more than 60% and the thinning rate increased by about 40%. A multi-objective optimization of forming indices was carried out by ideal point method and grey wolf optimizer. By comparing the forming results before and after optimization, the feasibility of using the proposed hollow mandrel was proved, and the hollow mandrel scheme of standard cylinder is therefore recommended.


2021 ◽  
Vol 11 (5) ◽  
pp. 2142
Author(s):  
Trung-Kien Le ◽  
Tuan-Anh Bui

Motorbike shock absorbers made with a closed die employ a tube-forming process that is more sensitive than that of a solid billet, because the tube is usually too thin-walled to conserve material. During tube forming, defects such as folding and cracking occur due to unstable tube forming and abnormal material flow. It is therefore essential to understand the relationship between the appearance of defects and the number of forming steps to optimize technological parameters. Based on both finite element method (FEM) simulations and microstructural observations, we demonstrate the important role of the number and methodology of the forming steps on the material flow, defects, and metal fiber anisotropy of motorbike shock absorbers formed from a thin-walled tube. We find limits of the thickness and height ratios of the tube that must be held in order to avoid defects. Our study provides an important guide to workpiece and processing design that can improve the forming quality of products using tube forming.


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