50 巻 (2009) 581 号 p. 570-574
A hot shear spinning process of cast aluminum alloy parts with an inclined roller was developed to improve the formability of the cast aluminum. Hot shear spinning has the function of eliminating dendrites and shrinkage cavities in cast aluminum alloys. The backward metal flow in the slope region of a blank was prevented by reducing wall thickness perpendicularly to the mandrel by means of the inclined roller, and thus the wall thickness does not return after passing the gap between the roller and mandrel. As the roller angle increased, the thickness return ratio decreased, and the ratio was almost zero above 30°. The surface crack length in the corner region of the spun blank was reduced by the use of an inclined roller. The elongation of the spun blank with the inclined roller was larger than that with a noninclined roller, whereas the tensile strength was smaller owing to the reduction in redundant deformation. In addition, the inclined rollers were effective in forming the step region of the blank.