In this work, cold bulge forming of an Aluminium-Magnesium (Al-Mg) sheet with a solid bulging medium is experimentally and numerically performed. Mechanical properties and thickness variations of Al-Mg sheet are evaluated before and after the forming process. The results indicated that the Al-Mg sheet has taken the desired shape without necking using the cold bulge forming process. Also, the experimental results showed significant improvements of 13 and 9. 7% in yield and ultimate tensile strengths of Al-Mg sheet after bulge forming. It is proved that the maximum thickness reduction of Al-Mg blank is less than 6% after cold bulge forming. Numerical simulations of cold bulge forming of Al-Mg sheet are conducted using Abaqus finite element software. For this purpose, many numerical models were created and analyzed to investigate the effects of bulge forming speed on the blank thickness variation for different Aluminium alloys. In these simulations, four different speed of 1, 5, 15 and 25 mm/min are used as forming speeds. Numerical results of bulge forming of Al-Mg sheet were compared with experimental measurements and good correlation, less than 2. 6% difference at critical zone, was observed between the results. Moreover, obtained results from numerical simulations for different Aluminium alloys showed that the thickness variations of formed Al-Mg sheet are more uniform by reducing the forming speed. Note also that, the less strength of material, the more uniform thickness variation is achievable along longitudinal direction of metal sheet.

The integral hydro-bulge forming (IHBF) process, also called shell hydroforming, is a die-less forming technique used to manufacture hollow parts from preforms made of sheet blanks cut and welded together. In this study, integral hydro-bulging of spherical vessels was investigated both numerically and experimentally. Numerical simulations were performed using Abaqus commercial software, and the numerical results were validated via comparison with those obtained from the experiments. The thickness distribution along the equatorial and meridian paths, sphericity of the formed vessel, and critical fluid pressure at which instability occurs were studied, and the effect of the number of lateral petals was investigated. For this study, an St12 steel sheet with a thickness of 0. 8 mm was used to make a spherical shell with 12 lateral petals and a diameter of 400 mm. The results showed that the use of preforms with more lateral petals leads to a more uniform thickness distribution and shape accuracy in the formation of spherical vessels. Furthermore, by increasing the number of petals from 8 to 16, the thickness decreased by 4. 2%. The maximum thickness reduction occurs in the 8-petal state, and the least thickness reduction occurs in the 12-petal state. The results show that the increase in the number of lateral petals leads to the increase in the critical fluid pressure. By doubling the number of lateral petals, fracture pressure increased by 74% consequently.

Hot metal gas forming of tubes can be used in various industries such as automotive and aerospace industries. In this process tube is formed at elevated temperatures, by using gas instead of fluid pressure. Lower required pressure and low power are its advantages in comparison to hydroforming process. In this paper, a hot metal gas bulging process of an aluminum alloy tube has been investigated by finite element method. In addition, The HMGF process was simulated by) Dynamic, Temp-Disp, Explicit (because of the temperature distribution along the tube length, whereas temperature was simplified and assumed to be uniform in analytical method. The bulge height parameter was investigated by changing the input variations such as internal pressure, outer diameter, die entry radius, initial tube length and initial tube wall thickness in numerical method. The numerical result shows that the input variations have significant effects on tube bulge height in this process.

Due to the low formability of aluminum alloys at ambient temperature, forming of these alloys is performed at high temperature. Research has shown that the results of simple tensile test to predict the materials behavior at high temperatures are not sufficiently accurate to predict the formability of aluminum tubes at high temperature. The mechanical properties of the tube are very important at high temperatures. In this study the formability of 6063 aluminum alloy tubes are investigated by free bulging test at temperature range 430oC to 600oC. Then the mechanical properties including flow stress, strain rate sensitivity coefficient and strength constant are obtained using tube multi-bulge test at temperature range 530oC to 580oC. For this purpose, hot metal tube gas forming process is used and the effect of process parameters such as the effect of temperature, pressure and time on the expansion ratio and height of the bulge are studied. The results show that the maximum expansion ratio is 58% at 580oC. Bursting pressure decreases from 1.9MPa to 0.6MPa with temperature increasing from 430oC to 600oC. The bulge height increases with increasing forming time at constant pressure. Also, with increasing temperature in the temperature range 530oC to 580oC the flow stress and strength constant decrease and strain rate sensitivity coefficient increases.

Computer aided simulation of three-dimensional deformation behavior of sheet metal during cold roll forming process is described In this simulation, the shape of deformed sheet metal is expressed by an approximated mathematical equation called "Shape Function". By means of this shape function, stress and strain distribution and dissipated energy in the deformed sheet metal can be calculated by a computerized incremental procedure using Hooks law in the elastic range and Levy - Mises equations in the plastic range. The optimum shape of deformed sheet can then be predicted by minimization of the calculated energy.By the simulation, it was possible to explain various characteristics of the cold roll forming process. The authors believe that using Levy - Mises equations simplifies the previously proposed methods and at the same time the results seem to be quite encouraging.

Aluminum alloys are desirable in industry due to their excellent high-strength to weight ratio, corrosion resistance, and weldability. However, at room temperature, the formability and the surface quality of the final product of these alloys are low. So in recent decade, new process, hot metal gas forming, has been introduced. This paper investigated new method of hot aluminum alloys forming using gas. Experimental test for bulge forming was designed and made. In addition to experimental test, finite element analysis of process was done. Results showed that hot metal gas forming provides highest forming temperature for aluminum alloy blank and with increasing blank temperature up to optimum temperature of hot forming, there is reduced pressure forming and significant improvement of formability. Results of experimental test and finite element analysis including determination of optimum temperature for forming of special aluminum alloy, maximum formability in this process, required forming pressure, minimum thickness, thickness and temperature distribution were conformed.