Abstract
In recent years, low-weight magnesium alloy parts have been widely applied to automobile manufacture. When functional rotating parts such as scroll rotor were made of magnesium alloys, remarkable weight saving and low moment of inertia of the rotating parts were achieved. However, the net shape forging of a scroll rotor using magnesium alloys has not been developed. In the present paper, we proposed a net shape forging process and an apparatus for forming a scroll rotor with a boss part using the magnesium alloy AZ31 at a low temperature such as 200 or 250°C in terms of the available forming temperatures. First, we analyzed the proposed forging process of AZ31 scroll rotor using rigid-plastic FEM program. Then, details of the forging process and apparatus were determined by experiments. One of the advantages of the proposed apparatus is that a uniform height of the scroll vane can be achieved using an air vent; hence, the use of a conventional backpressure adding system could be eliminated. Finally, we confirmed that a net-shaped AZ31 scroll rotor could be formed using the proposed forging process and apparatus.
