Formability of Al6061 Extruded Tube in Warm Hydroforming

2007 ◽  
Vol 340-341 ◽  
pp. 599-604 ◽  
Author(s):  
Young Seon Lee ◽  
Jung Hwan Lee ◽  
M.Y. Lee ◽  
Young Hoon Moon ◽  
T. Ishikawa
Keyword(s):  
Heat Treatment ◽  
Fe Analysis ◽  
Forming Limit ◽  
Bulge Test ◽  
Forming Process ◽  
Treatment Conditions ◽  
Hydroforming Process ◽  
Forming Temperature ◽  
Warm Hydroforming ◽  
Full Annealing

Formability of tube in elevated temperature is essential data to design the warm hydroforming process parameters, such as tube diameter, forming temperature and die geometries. Since the quantitative data of forming limit can be used to predict the failure on forming process, formability data available on the FE analysis is one of the very important information for the optimum design. In this study, the effect of heat treatment conditions and deformation temperature on the formability was investigated for the warm hydroforming of Al6061 tube. Full annealing and T6-treatment are applied for the heat treatment of Al6061 tubes. To evaluate the hydroformability, uni-axial tensile test and bulge test were performed at temperature ranges between room temperature and 300oC. The measured flow stresses were used as input parameters for the simulation of warm hydroforming process. The damage value and strain variation during hydroforming are analysed by FEM. A forming limit based on the ductile fracture criteria has been proposed by combining the results of experimental and FE analysis for the estimation of formability and optimization of warm hydroforming process.

Parametric Investigation of Circular and Elliptical Bulge Tests in Warm Hydroforming Process for AA5754-O Sheet

2011 ◽  
Vol 473 ◽  
pp. 594-601 ◽  
Author(s):  
Hasan Gedikli ◽  
Ömer Necati Cora ◽  
Muammer Koç
Keyword(s):  
Coefficient Of Friction ◽  
Sheet Material ◽  
Dome Height ◽  
Bulge Test ◽  
Test Model ◽  
Significant Finding ◽  
Blank Holder ◽  
Hydroforming Process ◽  
Forming Temperature ◽  
Warm Hydroforming

This study numerically investigated the effects of process parameter variations such as blank holder forces (800kN-1200kN), strain rates (0.0013/sec, 0.013/sec, 0.13/sec), coefficient of friction (0.05-0.15), temperature (150 °C, 260 °C) and apex angles (0º, 60º, 90º,120º) on warm hydroforming of AA 5754-O sheet blanks. Warm hydroforming process was simulated through hydraulic bulge test with circular and elliptical die openings. Dome height and sheet thinning were selected as control parameters for formability of AA 5754-O sheet blanks. Results showed that the dome height and formed blank thicknesses did not change significantly with the variation of coefficient of friction and blank holder force. Moreover, increasing forming temperature and non-isothermal conditions yielded slightly better formability. On the other hand, increase in strain rate, and elliptical type of bulge test cavity led to significant decreases in dome height and formed part thinning. Another significant finding was that the elliptical bulge test model and isothermal analyses did not reveal the effect of anisotropy for the sheet material concerned.

Microstructural Effect and Material Homogenization of Thermal-Hydroforming Magnesium Alloy Tubes

2011 ◽  
Vol 465 ◽  
pp. 459-462 ◽  
Author(s):  
Lin Wang ◽  
Luen Chow Chan ◽  
Ting Fai Kong
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Tensile Tests ◽  
Heat Treatment Condition ◽  
Material Strength ◽  
Forming Process ◽  
Engineering Strain ◽  
Treatment Conditions ◽  
Metal Forming Process ◽  
Microstructural Effect

The microstrctural evolution pre and post heat treatment is critical to achieve a successful product for metal forming process. This paper aims to investigate the microstructual effect of the magnesium alloy tubes undergone various heat treatment conditions to achieve material homogenization. The heat treatment conditions under various periods of time (1, 2, 6, 12 and 30 hours) at 400 °C were employed to investigate the microstructural effect on hydroforming magnesium tubes. The greatly reduced impurity embedded in grain boundaries and more uniform grain sizes do indicate the improvement of material strength and ductility. To validate the conclusion, corresponding tensile tests at the different temperatures (20 °C and 200 °C) were carried out. The increased engineering strain in two directions (hoop and longitudinal) implies that the microstructural evolution is unquestionably useful to enhance the ductility of the magnesium tubes. Subsequently, the tubes after optimal heat treatment condition at 400 °C for 6 hours were used to further carry out the thermal hydroforming process for validation. The defect-free hydroformed tubes were produced under the same working condition, which is unable to be achieved for tubes without the heat-treatment process.

Reliability Analysis of the Tube Hydroforming Process Based on Forming Limit Diagram

2005 ◽  
Vol 128 (3) ◽  
pp. 402-407 ◽  
Author(s):  
Bing Li ◽  
Don R. Metzger ◽  
Tim J. Nye
Keyword(s):  
Automotive Industry ◽  
Metal Forming ◽  
Tube Hydroforming ◽  
Forming Limit Diagram ◽  
Probability Of Failure ◽  
Alternative Methods ◽  
Forming Limit ◽  
Forming Process ◽  
Hydroforming Process ◽  
Free Bulging

Tube hydroforming is an attractive manufacturing process in the automotive industry because it has several advantages over alternative methods. In order to determine the reliability of the process, a new method to assess the probability of failure is proposed in this paper. The method is based on the reliability theory and the forming limit diagram, which has been extensively used in metal forming as the criteria of formability. From the forming limit band in the forming limit diagram, the reliability of the forming process can be evaluated. A tube hydroforming process of free bulging is then introduced as an example to illustrate the approach. The results show this technique to be an innovative approach to avoid failure during tube hydroforming.

Deformation Behaviour of Sheet Metals in Laser Assisted Hydroforming Processes

2005 ◽  
Vol 6-8 ◽  
pp. 361-368 ◽  
Author(s):  
Hans Kurt Tönshoff ◽  
J. Bunte ◽  
O. Meier ◽  
L. Engelbrecht
Keyword(s):  
Deformation Behaviour ◽  
Local Heating ◽  
Grain Structure ◽  
Forming Limit ◽  
Bulge Test ◽  
Capital Investments ◽  
Cold Forming ◽  
Small Form ◽  
Work Pressure ◽  
Forming Temperature

Cupping small form elements in hydroforming processes requires high work pressures and clamping forces and thus high capital investments for presses. Localised laser heating used during sheet metal hydroforming processes should reduce the necessary work pressure. By reducing the yield strength and the strain hardening using local heating, small form elements can be formed at very low pressures of 2 MPa, whereas cold forming requires pressures which are 20-50 times higher. Besides the proportion of forming temperature and work pressure, temperature distribution is very important and can be adjusted using a special laser beam forming optic or a scanning processing head. Line network analysises were carried out showing great improvements in the resulting plastic deformation distribution. In order to characterise the general improvement of the material’s formability, forming limit curves (FLC) were generated using the bulge-test. The results approve the extended forming limit of the laser assisted warm cupping process. Moreover, the mechanical properties and the grain structure of the form elements generated were determined. All investigations were carried out for a deep drawing steel, a 5182 aluminium alloy and an AZ31 magnesium alloy.

Warm Hydroformability and Mechanical Properties of Pre- and Post- Heat Treated Al6061 Tubes

2007 ◽  
Vol 29-30 ◽  
pp. 87-90 ◽  
Author(s):  
Hyae Kyung Yi ◽  
Jung Hwan Lee ◽  
Young Seon Lee ◽  
Young Hoon Moon
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Room Temperature ◽  
Cost Effective ◽  
Bulge Test ◽  
Axial Tensile ◽  
Heat Treated ◽  
Shaped Tube ◽  
Forming Temperature ◽  
Warm Hydroforming

Warm hydroformability and mechanical properties of pre- and post- heat treated Al6061 tubes were investigated in this study. For the investigation, as-extruded, fully annealed and T6- treated Al 6061 seamless tubes were prepared. To evaluate the hydroformability, uni-axial tensile test and free bulge test were performed at room temperature and 200ÓC. Also mechanical properties of hydroformed part at various pre- and post-heat treatments were evaluated by tensile test. The tensile test specimens were obtained from hexagonal shaped tube hydroformed at 200ÓC forming temperature. As a result, hydroformability of fully annealed tube is 25% higher than that of extruded tube. The tensile strength and elongation were more than 330MPa and 12%, respectively, when hydroformed part was T6 treated after warm hydroforming. However, hydroformed part using T6 pre treated tube represents low elongation, 8%. Therefore, the T6 treatment after hydroforming for as-extruded tube is proved to be the most cost-effective among various processing conditions.

scholarly journals Hydroforming Process for an Ultrasmall Bending Radius Elbow

2018 ◽  
Vol 2018 ◽  
pp. 1-15
Author(s):  
Shangwen Ruan ◽  
Lihui Lang ◽  
Yulong Ge
Keyword(s):  
Heat Treatment ◽  
High Performance ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Welding Process ◽  
Forming Process ◽  
Sealing Performance ◽  
Lap Welding ◽  
Hydroforming Process ◽  
Bending Radius

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.

Effect of Heat Treatment Conditions on Tube Hydroforming Characteristics of Aluminum Alloy

2013 ◽  
Vol 535-536 ◽  
pp. 275-278
Author(s):  
Myeong Han Lee ◽  
Young Chul Shin ◽  
Duk Jae Yoon
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Metal Forming ◽  
Tube Hydroforming ◽  
Treatment Processes ◽  
Forming Technology ◽  
Treatment Conditions ◽  
Compressive Loads ◽  
Hydroforming Process

Tube hydroforming is a metal forming technology that utilizes internal pressure and axial compressive loads to generate designed product shapes with complex sections from tubular materials. The tube hydroforming process has been used in the automotive, aircraft, and bicycle industries for many years. With the pursuit of lighter bicycles, aluminum alloys have been utilized as an alternative to steel. To obtain adequate strength, the aluminum alloys should undergo heat treatment processes before being used. However, the mechanical properties of the alloys vary with the tempering conditions. This paper aims to evaluate the effects of tube hydroforming characteristics on different kinds of tempered aluminum alloys. Based on numerical simulations, suitable tube hydroforming processing conditions for each tempered aluminum alloy are suggested.

Multi-Objective Optimization of the Hydroforming Process Considering Different Plastic Yield Criteria

2015 ◽  
Vol 651-653 ◽  
pp. 1394-1399 ◽  
Author(s):  
Vito Piglionico ◽  
Antonio Piccininni ◽  
Gianfranco Palumbo ◽  
Luigi Tricarico
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Forming Limit ◽  
Al Alloy ◽  
Algorithm Optimization ◽  
Explicit Finite Element ◽  
Yield Criteria ◽  
Multi Objective ◽  
Hydroforming Process ◽  
Warm Hydroforming

The present work aims at determining the optimal working conditions for the manufacturing of the AA6061-T6 Al alloy by the hydroforming process. As case study a stepped geometry was used. A numerical model was created using the commercial explicit Finite Element code LS-DYNA. The plastic behaviour of the investigated alloy was modelled implementing experimental data (flow stress curves, Lankford coefficients and Forming Limit Curves) and using two different yield criteria: an anisotropic one (Barlat ‘89) and the conventional isotropic one (Von Mises). Finite Element models were tuned using experimental data from warm hydroforming tests: comparing both the sheet thinning and the die cavity filling, quite different friction conditions had to be supposed for obtaining a good fitting with both the yield criteria.Finite Element models were finally used for evaluating the working range of the hydroforming process: results from a CCD simulation plan were imported within an integration platform (modeFRONTIER) to evaluate the optimal hydroforming conditions based on a multi-objective genetic algorithm optimization. Quite different results in terms of optimization and working range were obtained when adopting different yield criteria.

The Effects of the Heating Conditions on the Hydro-Formability of the Aluminum Alloys at High Temperatures

2005 ◽  
Vol 475-479 ◽  
pp. 3307-3310 ◽  
Author(s):  
B.J. Kim ◽  
S.M. Son ◽  
K.S. Park ◽  
Young Hoon Moon
Keyword(s):  
Aluminum Alloys ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Heating Time ◽  
Age Hardening ◽  
Dynamic Strain ◽  
Forming Process ◽  
Before And After ◽  
Hydroforming Process ◽  
Warm Hydroforming

Modern automobiles are built with a steadily increasing variety of materials and semifinished products. The traditional composition of steel sheet and cast iron is being replaced with other materials such as aluminum and magnesium. But low formability of these materials has prevented the application of the automotive components. The formability can be enhanced by conducting the warm hydroforming using induction heating device which can raise the temperature of the specimen very quickly. The specimen applied to the test is AA6061 extruded tubes which belong to the age-hardenable aluminum alloys. But in the case of AA6061 age hardening occurs at room temperature or at elevated temperatures before and after the forming process. In this study the effects of the heating condition such as heating time, preset temperature, holding time during die closing and forming time on the hydroformability are analyzed to evaluate the phenomena such as dynamic strain hardening and ageing hardening at high temperatures after the hydroforming process.

scholarly journals Experimental investigation of forming limit curves and deformation features in warm forming of an aluminium alloy

2016 ◽  
Vol 232 (3) ◽  
pp. 465-474 ◽  
Author(s):  
Zhutao Shao ◽  
Qian Bai ◽  
Nan Li ◽  
Jianguo Lin ◽  
Zhusheng Shi ◽  
...  
Keyword(s):  
Aluminium Alloy ◽  
Elevated Temperatures ◽  
Warm Forming ◽  
Dome Height ◽  
Forming Limit ◽  
Thickness Variation ◽  
Forming Process ◽  
Deformation Features ◽  
Forming Temperature ◽  
Forming Limit Curves

The determination of forming limit curves and deformation features of AA5754 aluminium alloy are studied in this article. The robust and repeatable experiments were conducted at a warm forming temperature range of 200 °C–300 °C and at a forming speed range of 20–300 mm/s. The forming limit curves of AA5754 at elevated temperatures with different high forming speeds have been obtained. The effects of forming speed and temperature on limiting dome height, thickness variation and fracture location are discussed. The results show that higher temperatures and lower forming speeds are beneficial to increasing forming limits of AA5754; however, lower temperatures and higher forming speeds contribute to enhancing the thickness uniformity of formed specimens. The decreasing forming speed and increasing temperature result in the locations of fracture to move away from the apexes of formed specimens. It is found that the analysis of deformation features can provide a guidance to understand warm forming process of aluminium alloys.

Sign in / Sign up

Export Citation Format

Share Document