scholarly journals Influence of Internal Pressure and Axial Compressive Displacement on the Formability of Small-Diameter ZM21 Magnesium Alloy Tubes in Warm Tube Hydroforming

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 674 ◽  
Author(s):  
Hajime Yasui ◽  
Taisuke Miyagawa ◽  
Shoichiro Yoshihara ◽  
Tsuyoshi Furushima ◽  
Ryuichi Yamada ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Internal Pressure ◽  
Deformation Behavior ◽  
Tube Hydroforming ◽  
Small Diameter ◽  
Forming Limit ◽  
Outer Diameter ◽  
Fe Method ◽  
Zm21 Magnesium Alloy ◽  
Forming Defects

In this study, the influence of internal pressure and axial compressive displacement on the formability of small-diameter ZM21 magnesium alloy tubes in warm tube hydroforming (THF) was examined experimentally and numerically. The deformation behavior of ZM21 tubes, with a 2.0 mm outer diameter and 0.2 mm wall thickness, was evaluated in taper-cavity and cylinder-cavity dies. The simulation code used was the dynamic explicit finite element (FE) method (FEM) code, LS-DYNA 3D. The experiments were conducted at 250 °C. This paper elucidated the deformation characteristics, forming defects and forming limit of ZM21 tubes. Their deformation behavior in the taper-cavity die was affected by the axial compressive direction. Additionally, the occurrence of tube buckling could be inferred by changes of the axial compression force, which were measured by the load cell during the processing. In addition, grain with twin boundaries and refined grain were observed at the bended areas of tapered tubes. The hydroformed samples could have a high strength. Moreover, wrinkles, which are caused under a lower internal pressure condition, were employed to avoid tube fractures during the axial feeding. The tube with wrinkles was expanded by a straightening process after the axial feed. It was found that the process of warm THF of the tubes in the cylinder-cavity die was successful.

scholarly journals Material Deformation Behavior in T-Shape Hydroforming of Metal Microtubes

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 199 ◽  
Author(s):  
Hajime Yasui ◽  
Shoichiro Yoshihara ◽  
Shigeki Mori ◽  
Kazuo Tada ◽  
Ken-ichi Manabe
Keyword(s):  
Pure Copper ◽  
Material Behavior ◽  
Tube Length ◽  
Process Window ◽  
Forming Limit ◽  
Outer Diameter ◽  
Friction Resistance ◽  
Buckling Resistance ◽  
The Many ◽  
Forming Defects

In this study, the material behavior in the T-shape microtube hydroforming (MTHF) of pure copper and stainless-steel SUS304 microtubes with an outer diameter of 500 µm and wall thickness of 100 µm was examined experimentally and numerically. This paper elucidates the basic deformation characteristics, the forming defects, and the forming limit as well as the effects of lubrication/friction and tube length. The hydroformability (bulge height) of the SUS304 microtube was shown to be higher than that of the copper microtube because of the high buckling resistance of SUS304. Good lubrication experimentally led to the high hydroformability of T-shape forming. The length of the microtube significantly affects its hydroformability. Friction resistance increases with increasing tube length and restricts the flow of the microtube material into the die cavity. By comparing the T-shape and cross-shape MHTF characteristics, we verified the hydroformability of the T-shape microtube to be superior to that of the cross-shape microtube theoretically and experimentally. In addition, the process window for T-shape MTHF had a narrower “success” area and wider buckling and folding regions than that for cross-shape MTHF. Furthermore, conventional finite element (FE) modeling without consideration of the grains was valid for MTHF processes owing to the many grains in the thickness direction.

Study on Forming Feasibility of AISI-5140 Triple Valve by Multi-Way Loading: From Aspect of Geometric Parameters

2011 ◽  
Vol 299-300 ◽  
pp. 982-987 ◽  
Author(s):  
Zhi Chao Sun ◽  
Jiang Hui Wang ◽  
He Yang
Keyword(s):  
Geometric Dimension ◽  
Forming Limit ◽  
Stress And Strain ◽  
Outer Diameter ◽  
Forming Load ◽  
Inner Diameter ◽  
Forming Condition ◽  
Triple Valve ◽  
Forming Defects

Multi-way loading technology provides an efficient method to form integral triple valve parts. However, some forming defects such as cracking and folding are prone to occur, which will weaken the forming limit and quality of formed triple valves. Based on numerical simulation, taking forming load, damage, stress, strain and folding as objectives the forming limit and feasibility were studied by changing geometric dimension of billet and triple valve to be formed. The results showed that (1) for a given billet, as the inner diameter of triple valve increasing, the forming load, maximum damage value, stress and strain increased, i.e. the larger the inner diameter of triple valve the more difficult to form; (2) For triple valves with a given inner-outer diameter ration the maximum damage, maximum stress and strain values increased as triple valve outer diameter decreasing while forming load changed a little. The possibility of folding would augment with the increase of inner-outer diameter ratio d/D, when d/D≥0.8, folding occurred under the forming condition in this paper.

Forming Limit of Magnesium Alloy Sheet in Hydromechanical Deep Drawing

2012 ◽  
Vol 482-484 ◽  
pp. 2086-2089 ◽  
Author(s):  
Xian Chang Mao ◽  
Ming Guang Wang
Keyword(s):  
Magnesium Alloy ◽  
Internal Pressure ◽  
Deep Drawing ◽  
Alloy Sheet ◽  
Forming Limit ◽  
Az31b Magnesium Alloy ◽  
Hydromechanical Deep Drawing ◽  
Magnesium Alloy Sheet ◽  
Deformation Behaviors ◽  
Az31b Magnesium Alloy Sheet

The experimental research on the hydromechanical deep drawing of AZ31B magnesium alloy sheet was conducted in this paper. The deformation behaviors and the influence of internal pressure on its formability are investigated, moreover, the fracture behaviors of the obtained workpieces are discussed. The experimental results show that the formability of AZ31B magnesium alloy sheet in hydromechanical deep drawing is poorer than that in mechanical deep drawing at room temperature because the internal pressure fails to work effectively due to the weak plastic deformation capacity and the premature fracture of the kind alloy.

Warm Bulge Forming of Small Diameter A1100 Aluminium Tube

2018 ◽  
Vol 920 ◽  
pp. 149-154
Author(s):  
Satoshi Mitsui ◽  
Taisuke Miyagawa ◽  
Hajime Yasui ◽  
Shoichiro Yoshihara
Keyword(s):  
Size Effect ◽  
Internal Pressure ◽  
Medical Devices ◽  
Loading Rate ◽  
Small Diameter ◽  
Outer Diameter ◽  
Deformation Characteristics ◽  
Pressure Loading

In recent years, the small diameter aluminium tube has been widely utilized for chemical instruments and medical devices. These instruments are should be minimized since the usage of the small diameter tubes has been extremely increased. However, the deformation characteristics could not be scaled down similarly to the material dimensions due to the size effect. Thus, tube bulge forming is necessary to clarified the deformation characteristics of the small diameter tubes. In this paper, the formability of the warm tube bulge forming by using the small diameter A1100 aluminium tube with 2.0 mm outer diameter and 0.2 mm thickness has been investigated. As the results, the effect of the different temperature and the different internal pressure on the tube bulge forming of the small diameter A1100 aluminium tubes was clarified. Furthermore, it was confirmed that the variation of the internal pressure loading rate affected the deformation characteristics of the tubes.

Optimization of Tube Hydroforming Process Using Probabilistic Constraints on Failure Modes

2011 ◽  
Vol 62 ◽  
pp. 21-35 ◽  
Author(s):  
Anis Ben Abdessalem ◽  
A. El Hami
Keyword(s):  
Failure Modes ◽  
High Reliability ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Forming Limit Diagram ◽  
Plastic Instability ◽  
Probabilistic Constraints ◽  
Forming Limit ◽  
Reliability Based Design ◽  
Hydroforming Process

In metal forming processes, different parameters (Material constants, geometric dimensions, loads …) exhibits unavoidable scatter that lead the process unreliable and unstable. In this paper, we interest particularly in tube hydroforming process (THP). This process consists to apply an inner pressure combined to an axial displacement to manufacture the part. During the manufacturing phase, inappropriate choice of the loading paths can lead to failure. Deterministic approaches are unable to optimize the process with taking into account to the uncertainty. In this work, we introduce the Reliability-Based Design Optimization (RBDO) to optimize the process under probabilistic considerations to ensure a high reliability level and stability during the manufacturing phase and avoid the occurrence of such plastic instability. Taking account of the uncertainty offer to the process a high stability associated with a low probability of failure. The definition of the objective function and the probabilistic constraints takes advantages from the Forming Limit Diagram (FLD) and the Forming Limit Stress Diagram (FLSD) used as a failure criterion to detect the occurrence of wrinkling, severe thinning, and necking. A THP is then introduced as an example to illustrate the proposed approach. The results show the robustness and efficiency of RBDO to improve thickness distribution and minimize the risk of potential failure modes.

Dynamic Deformation Behavior of As-Extruded Mg-Gd-Y Magnesium Alloy and the Microstructural Evolution

2011 ◽  
Vol 284-286 ◽  
pp. 1579-1583
Author(s):  
Ping Li Mao ◽  
Zheng Liu ◽  
Chang Yi Wang ◽  
Feng Wang
Keyword(s):  
Magnesium Alloy ◽  
Strain Rate ◽  
Deformation Behavior ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Deformation ◽  
Strain Rates ◽  
Compression Axis ◽  
Deformation Localization ◽  
Dynamic Deformation Behavior

The dynamic deformation behavior of an as-extruded Mg-Gd-Y magnesium alloy was studied by using Split Hopkinson Pressure Bar (SHPB) apparatus under high strain rates of 102 s-1 to 103s-1 in the present work, in the mean while the microstructure evolution after deformation were inspected by OM and SEM. The results demonstrated that the material is not sensitive to the strain rate and with increasing the strain rate the yield stress of as-extruded Mg-Gd-Y magnesium alloy has a tendency of increasing. The microstructure observation results shown that several deformation localization areas with the width of 10mm formed in the strain rates of 465s-1 and 2140s-1 along the compression axis respectively, and the grain boundaries within the deformation localization area are parallel with each other and are perpendicular to the compression axis. While increasing the strain rate to 3767s-1 the deformation seems become uniform and all the grains are compressed flat in somewhat. The deformation mechanism of as-extruded Mg-Gd-Y magnesium alloy under high strain rate at room temperature was also discussed.

Sign in / Sign up

Export Citation Format

Share Document