Investigation of the Effect of Different Forming Pressure Curves on Formability of AA1050 Tubes in Warm Hydroforming Process

Reduction of weight and increase of corrosion resistance are among the advantages of applications of aluminum alloys in the automotive industry. Low formability at room temperature is the major problem in the forming of these alloys. This problem is due to alloy elements that limit the number of slip planes at room temperature. Forming at a high temperature can improve the formability of metals. In this paper, the warm hydroforming of AA1050 aluminum tubes has been studied numerically. A warm tube hydroforming setup was designed and fabricated. Aluminum tubes were formed at high temperatures. Numerical simulation of process is performed using MSC. Marc commercial software and thickness distribution were studied at various temperatures. Results showed that increasing temperature leads to a much better thickness distribution. The pressure curves which were obtained using available equations for forming at room temperature have been modified to decrease thinning in the final part. Simulations were performed in two states which are called constrained bulge and free bulge. To produce a part without any wrinkling and also to obtain minimum thinning, an axial feeding curve is suggested.