EFFECT OF HEAT TREATMENT ON THE HYDROFORMABILITY OF 1060 AA 1MM THICK SHEET METAL (original) (raw)
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Effect of Heat Treatment on the Hydroformability of 1060 Aa 1MM Thick
2015
Sheet metal technologies are challenged especially by the improvement in the automotive industry in the last decades to fulfill the customer expectations, safety requirements and market competitions, new production technologies have been implemented [1]. In this work the sheet metal used is 1060AA 1mm thick Aluminum alloy usually used for its light weight, high corrosion resistant, easy to recyclables and high strength to weight ratio. This sheet metal is to be formed by hydroforming process which used the hydraulic pressure as a punch to force the sheet metal to take the shape of the die cavity and study the formability of this alloy under different heat treatment procedures.
Warm Hydroforming of Lightweight Metal Sheets
Hydroforming is well known in steel applications for automotive industry, where complicated shapes can be get with high strength to weight ratios. Nevertheless, the poor formability of light alloys at room temperature has limited the application of hydroforming technology for aluminum and magnesium parts. Increasing the temperature of these materials allows substantially greater elongation without fracture. Warm forming strategy is applied in conventional processes, such as rolling and forging, in order to get complex shapes, but still rare in hydroforming technology. This is the technical base of this research project: the development of the hydroforming process at warm working temperatures. The main tasks of the initial phases of the research were the material characterization, and the heated fluid and tooling system design and set up for warm hydroforming of lightweight alloys. Once these goals were accomplished the present paper shows the obtained results. The uniaxial tensile d...
Investigations on Deformation Behavior of AA5754 Sheet Alloy Under Warm Hydroforming Conditions
Journal of Manufacturing Science and Engineering, 2011
In an ongoing quest to realize low-mass transportation vehicles with enhanced fuel efficiency, deformation characteristics of Al5052 and Al6061 were investigated. In the first part of this study, material behavior of Al5052 and Al6061 sheet alloys were investigated under different process (temperature and strain rate) and loading (uniaxial vs. biaxial) conditions experimentally. With the biaxial, hydraulic bulge tests, flow stress curves up to 60-70% strain levels were obtained whereas it was limited to 3030% strain levels in tensile tests. The microstructure analysis showed that the change of grain size due to the effects of elevated temperatures and strain rates were not significant; therefore, it was concluded that the decrease in the flow stress at high temperature levels was mainly due to the thermally activated dislocation lines. In the second part, the effect of the temperature and the pressure on the formability was further investigated in a set of closed-die warm hydroforming experiments. The test results showed that a linearly increasing pressure profile up to 3020 MPa levels did not have a significant effect on the die filling ratios and thinning of the parts when a uniform temperature distribution of 300°C was applied. Finally, in the third part of the study, finite element models were developed for the same closed-die hydroforming geometry using the material behavior models obtained from bulge and tensile tests. Flow stress curves obtained from tests were compared in terms of predicting the cavity filling ratios and thinning profiles from the experiments. Based on the comparison, it was revealed that flow stress curves obtained from the warm hydraulic bulge tests provided accurate predictions at high strain levels (i.e., e > 0:4, when part filling is above 80%) while the flow stress curves from the tensile tests did so at low strain levels (i.e., e < 0:2, when cavity filling is below 80%). On the other hand, comparison of thinning values indicated that flow stress curves from bulge tests yielded good agreement with the experimentally measured values in general. Therefore, it can be recommended that the bulge test results should be used whenever available in order to conduct accurate numerical analyses for warm sheet hydroforming where complex geometry and loading conditions exist.
Materials & Design, 2011
This study aimed to determine the proper combinations of numerical modeling conditions (e.g. solver, element type, material model) for warm hydroforming of AA5754-O aluminum alloy sheets. Assessment of finite element analyses (FEA) is based on comparison of numerical results and experimental measurements obtained from closed-die forming, hydraulic bulge and tensile tests at different temperature (25-300°C) and strain rate (0.0013-0.013 1/sec) levels. Thinning (% t) and cavity filling ratios (CFR) on the formed parts were taken as comparison parameters. Several numerical analyses employing different element types, solution methods and material models were performed using the commercially available FEA package LS-Dyna to determine the best combination of modeling options to simulate the actual warm hydroforming operation as accurately as possible. Analyses showed that relatively better predictions were obtained using isotropic material model, shell elements and implicit solution technique when compared with experimental results.
A Systematic Review of Sheet Metal Hydro Forming Process
Hydro forming technology is very useful for the light weight material include low carbon/mild steel for chassis and side rails, aluminium, and its alloy for automotive body, stainless steel for exhaust system part. There are many process Parameters like as hydraulic pressure, blank-holding force, die radius, material properties, and coefficient of friction affect thee sheet hydro forming process. Purposes of the study can be improve the competitiveness of sheet hydro forming by new setup to reduced various defects , increase the production rate of auto body parts at lower initial investment cost.
Journal of Materials Processing Technology, 2008
The procedure of hydroforming belongs to one of the modern methods of sheet and tube design, usually of complex configuration. Research in the field of plastic forming using fluids usually relates to the analysis of important parameters that would enable high-quality design of elements and execution of the process in stable conditions. The hydroforming process of welded sheets found its application in manufacturing of tanks and other sheet parts in automotive industry, where, in addition to technical and technological characteristics of the obtained piece, it is necessary to achieve stability of the process and its economic feasibility. Experimental research in this paper had been aimed at the analysis of results and modeling of working fluid pressure during hydroforming of welded sheets of two kinds of material (St 37 and Al 99.5) for two sheet thicknesses (1.5 mm and 2.0 mm). Modeling was done by regression method, whose analysis is the determination of functional relationships between a dependent variable and two independent variables. Application of mathematical modeling method enabled working fluid pressure which confirmed the impact of input variables of hydroforming process (yield strength and sheets thickness) onto the values of working fluid pressure. Experimental results obtained for working fluid pressure enabled easier planning and projection of hydroforming process.
An Experimental Study of the Sheet Hydroforming Process
Sixth International Conference on Advances in Civil Structural and Mechanical Engineering CSM 2018, 2018
Hydroforming of aluminum sheets is a plastic deformation process largely used in automotive industry. Among the different hydroforming processes, the Flexform is the one in which the punch is replaced by a fluid cell. This cell consists of a rubber membrane that is filled with a controlled pressure fluid that will deform the sheet in the tool. A rigid die is used for obtaining the shape of the workpiece. For obtaining a sound product a balance between the pressure fluid and the blank material and geometry must be assured. The paper presents experiments carried out for analyzing the influence of the die geometry, the blank thickness and the fluid pressure toward the product accuracy, in terms of thickness and shape variations. The results will be useful in process modeling and in estimation of hydro-deformability of aluminum sheets.
Investigations on forming of aluminum 5052 and 6061 sheet alloys at warm temperatures
Materials & Design (1980-2015), 2010
In an ongoing quest to realize low-mass transportation vehicles with enhanced fuel efficiency, deformation characteristics of Al5052 and Al6061 were investigated. In the first part of this study, material behavior of Al5052 and Al6061 sheet alloys were investigated under different process (temperature and strain rate) and loading (uniaxial vs. biaxial) conditions experimentally. With the biaxial, hydraulic bulge tests, flow stress curves up to 60-70% strain levels were obtained whereas it was limited to 3030% strain levels in tensile tests. The microstructure analysis showed that the change of grain size due to the effects of elevated temperatures and strain rates were not significant; therefore, it was concluded that the decrease in the flow stress at high temperature levels was mainly due to the thermally activated dislocation lines. In the second part, the effect of the temperature and the pressure on the formability was further investigated in a set of closed-die warm hydroforming experiments. The test results showed that a linearly increasing pressure profile up to 3020 MPa levels did not have a significant effect on the die filling ratios and thinning of the parts when a uniform temperature distribution of 300°C was applied. Finally, in the third part of the study, finite element models were developed for the same closed-die hydroforming geometry using the material behavior models obtained from bulge and tensile tests. Flow stress curves obtained from tests were compared in terms of predicting the cavity filling ratios and thinning profiles from the experiments. Based on the comparison, it was revealed that flow stress curves obtained from the warm hydraulic bulge tests provided accurate predictions at high strain levels (i.e., e > 0:4, when part filling is above 80%) while the flow stress curves from the tensile tests did so at low strain levels (i.e., e < 0:2, when cavity filling is below 80%). On the other hand, comparison of thinning values indicated that flow stress curves from bulge tests yielded good agreement with the experimentally measured values in general. Therefore, it can be recommended that the bulge test results should be used whenever available in order to conduct accurate numerical analyses for warm sheet hydroforming where complex geometry and loading conditions exist.
Cold and Warm Hydroforming of AA754‐O Sheet: FE Simulations and Experiments
2011
The sheet hydroforming with punch (SHF‐P) process offers great potential for low and medium volume production, especially for forming: (1) lightweight sheet materials such as aluminum (Al) and magnesium (Mg) alloys and (2) thin gage high strength steels (HSS). Mg and Al alloys are being increasingly considered for automotive applications, primarily due to their lightweight and high strength‐to‐weight ratios. However, there is limited experience‐based knowledge of process parameter selection and tool design for SHF‐P of these materials. Thus, there is a need for a fundamental understanding of the influence of process parameters on part quality. This paper summarizes analyses of the SHF‐P process of AA5754‐O sheet using finite element (FE) simulations. FE simulations and preliminary experiments of SHF‐P were conducted to determine the process parameters (blank holder force versus punch stroke and pot pressure versus stroke) to form a challenging shape (a cylindrical cup with a reverse...