Process parameters effect on a rectangular tube hydro-forming with magnesium alloy

Abstract

Due to the light weight and electromagnetic interference shielding capabilities in magnesium alloy material, it is widely utilized in 3C electronic components and automobile parts. However, its formability is very poor due to the phenomenon of negative strain hardening rate appearing in large strain deformation range, so it is usually formed as die casting or casting styles leads to much scrap, and manufacturing cost is thus increased. The objective of this study is to investigate the process parameters effect on a rectangular tube hydro-forming with magnesium alloy. AZ31 magnesium alloy circular tube is used as the billet material for hydroforming with hydraulic pressure as the main forming power combined with the mechanically auxiliary force from the punch to fabricate the rectangular tube products. A finite element based software is utilized to investigate the forming characteristics of the rectangular tube hydro-forming, by changing process parameters such as punch velocity, hydraulic pressure and tool-workpiece interface friction etc. to investigate the material flow of tube filling, wall thickness variations, and stress and strain distributions. And the abductive network is then applied to synthesize the data sets obtained from the numerical simulations and a prediction model is established. From the prediction model, product dimensions of corner radius and minimum tube thickness may be estimated in advance when the process variables have been set. The results show that proper mechanical force can help material flow, prevent large strain deformation from falling into the area of negative strain hardening rate, enhance magnesium alloy to become easy in forming and make tube may be formed successfully.