Investigation about the Oil Pressure Rate in the Warm Hydroforming of an Al-Mg Alloy Component

2016 ◽  
Vol 716 ◽  
pp. 963-972
Author(s):  
Gianfranco Palumbo ◽  
Antonio Piccininni ◽  
Pasquale Guglielmi ◽  
Vito Piglionico ◽  
Donato Sorgente ◽  
...  
Keyword(s):  
Strain Rate ◽  
Mg Alloy ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Integration Platform ◽  
Force Profile ◽  
Hydroforming Process ◽  
Cavity Filling ◽  
Warm Hydroforming ◽  
High Level

In this work, the hydroforming process in warm conditions was used for manufacturing an Al-Mg alloy (AA5754) benchmark component displaying different strain levels due to its geometry. The attention was focused on the effect of the rate to increase the forming pressure (PR), strictly related to the strain rate the material is subjected to. In fact, preliminary tensile and Nakajima tests (both at room temperature and in warm conditions) revealed that the mechanical and formability properties of the investigated alloy are strongly affected by the strain rate. Warm Hydroforming tests were conducted in order to investigate both the working temperature and the parameter PR. The Blank Holder Force profile was varied according to an experimentally determined profile able to avoid oil leakages. Experimental results were collected in terms of output variables related to the die cavity filling and to the strain level reached on the component: in such a way a multi-objective optimization could be carried out using the commercial integration platform modeFRONTIER. The best compromise between the high level of the component deformation and the cycle time could be obtained by conducting the warm hydroforming process at the temperature of 250°C and setting the parameter PR equal to 0.1 MPa/sec.

The Formability and Hot Stamping of Magnesium Alloy Sheets

2014 ◽  
Vol 1063 ◽  
pp. 215-218 ◽  
Author(s):  
Guang Sheng Huang ◽  
Li Fei Wang ◽  
Fu Sheng Pan ◽  
Ming Tu Ma
Keyword(s):  
Magnesium Alloy ◽  
Strain Rate ◽  
Hot Stamping ◽  
Alloy Sheet ◽  
Mg Alloys ◽  
Mg Alloy ◽  
Az31 Magnesium Alloy ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Cold Stamping

Mg alloy is a potential material to be used in automobile, especially in the stamping products. Through texture weakening, temperature increasing, strain rate decreasing, blank holder force controlling, lubrication choosing and so on, the formability of AZ31 magnesium alloy is improved so that the cold stamping on some simple products can be conducted. However, on the complicated products, hot stamping should be considered. Temperature has an important effect on the formability of Mg alloy sheet. As the temperature increasing, the strength of Mg alloys sheet decreases while the formability increases. Hot stamping process is an effective way to broaden the using of Mg alloys.

Numerical Simulation Research on Springback Controlling Methods of Aluminum Alloy Panel during Hydroforming

2016 ◽  
Vol 851 ◽  
pp. 163-167
Author(s):  
Dong Yan Lin ◽  
Yi Li
Keyword(s):  
Numerical Simulation ◽  
Aluminum Alloy ◽  
Process Parameters ◽  
Orthogonal Experiment ◽  
Blank Holder Force ◽  
Scoring Method ◽  
Simulation Research ◽  
Blank Holder ◽  
Hydroforming Process

The hydroforming process of the aluminum alloy panel was simulated by the software DYNAFORM. The effects of process parameters (blank holder force, depth of panel and height of draw bead) on springback of the aluminum alloy were investigated. The max springback of the panel was analyzed by weighted scoring method. Then the process parameters were synthetically optimized for the max positive and negative springback. The results showed that the height of draw bead affects obviously the comprehensive springback of the panel. The optimization of the process parameters obtained by the orthogonal experiment can effectively reduce the max springback of the panel.

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.

The Effect of Polyurethane Hardness on the New Die-Set of Sheet Hydroforming Process Parameters

2012 ◽  
Vol 152-154 ◽  
pp. 1623-1627
Author(s):  
Morteza Hosseinzadeh
Keyword(s):  
Process Parameters ◽  
Thickness Distribution ◽  
Effective Parameters ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Sheet Hydroforming ◽  
Die Set ◽  
Hydroforming Process

In recent years, several sheet hydroforming methods have been introduced by researchers. Despite the advantages of these methods, they have some limitations. The author [1] already proposed a novel sheet hydroforming method that is a combination of the standard and hydromechanical sheet hydroforming processes. The proposed method has the advantages of both processes and eliminates their limitations. In this method, a polyurethane diaphragm was used as a part of die-set to control the blank holder force. In this paper, the effect of polyurethane hardness on the effective parameters of the combined sheet hydroforming die-set such as forming pressure, thickness distribution of formed cup and maximum thinning zone of formed cup was investigated experimentally. It was shown that a softer polyurethane needs to a higher oil pressure to prevent wrinkling in the flange of the part. And tearing occurs at higher level of forming pressure. Also it was shown that by softer polyurethane, better thickness distribution was obtained.

A Modified Peric Model for Al-Mg Alloy Sheet with Rate-Independent Initial Yield Stress at Warm Temperatures

2019 ◽  
Vol 287 ◽  
pp. 3-7
Author(s):  
Yong Zhang ◽  
Qing Zhang ◽  
Yuan Tao Sun ◽  
Xian Rong Qin
Keyword(s):  
Flow Stress ◽  
Plastic Strain ◽  
Strain Rate ◽  
Yield Stress ◽  
Constitutive Models ◽  
Mg Alloy ◽  
Initial Yield Stress ◽  
Initial Yield ◽  
Rate Dependent ◽  
Dependent Flow

The constitutive modeling of aluminum alloy under warm forming conditions generally considers the influence of temperature and strain rate. It has been shown by published flow stress curves of Al-Mg alloy that there is nearly no effect of strain rate on initial yield stress at various temperatures. However, most constitutive models ignored this phenomenon and may lead to inaccurate description. In order to capture the rate-independent initial yield stress, Peric model is modified via introducing plastic strain to multiply the strain rate, for eliminating the effect of strain rate when the plastic strain is zero. Other constitutive models including the Wagoner, modified Hockett–Sherby and Peric are also considered and compared. The results show that the modified Peric model could not only describe the temperature-and rate-dependent flow stress, but also capture the rate-independent initial yield stress, while the Wagoner, modified Hockett–Sherby and Peric model can only describe the temperature-and rate-dependent flow stress. Moreover, the modified Peric model could obtain proper static yield stress more naturally, and this property may have potential applications in rate-dependent simulations.

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