2011 年 77 巻 775 号 p. 573-581
Magnesium has the smallest specific gravity in the structural metallic material applied to automotive parts. It is expected to be suitable light material to meet the increasing requirements of a vehicle weight reduction in recent years. However, as magnesium alloy has low forgeability due to its crystal structure, the forged magnesium application is quite few in automotive parts. In this research, the effect of forging rate for the aluminum-zinc system magnesium alloy casting on the crystal grain size, the strength characteristic etc. have been investigated in order to clarify the possibility of the cast- forge method of the magnesium and apply this method to an actual parts in automotive car. As a result, it is proved that the cast- forge method has high possibility as the manufacturing process to be applied for magnesium parts. By using this developed process and designing preform with proper shape with CAE, the final dimension of part and higher strength can be attained at only one stage forging.