Papers by Author: Akira Kamiya

Abstract: Cross-roll rolling with different rolling routes (unidirectional rolling and reverse rolling) was carried out on a commercial Mg alloy sheets. In the cross-roll rolling, the roll axis was tilted by 7.5 degrees against the transverse direction. As a result of the Erichsen tests at 433 – 493 K, the stretch formability of the reverse cross-rolled specimen was higher than that of the unidirectional cross-rolled specimen. The reverse cross-rolled specimen showed lower average Lankford value compared with the unidirectional cross-rolled specimen. This is likely to be responsible for the enhanced stretch formability of the reverse cross-rolled specimen. The higher stretch formability was attributed to reduction of (0002) texture intensity, which was originated from random grain distribution.

Abstract: In this study, two different cross rolling processes, which are effective rolling processes for a reduction of (0002) plane texture, are introduced. In the first cross rolling process, a sheet specimen is rotated around the rolling plane normal after each pass. In the second cross rolling process, the roll axis is tilted against the transverse direction (TD) in the rolling direction (RD) - TD plane. The two cross-rolling processed were carried out on a AZ31 alloy, and the press formability of cross-rolled sheets was compared with that of unidirectionally rolled sheets determined by Erichsen tests at 433 – 493 K. Both the cross-rolled specimens exhibited a high press formability, compared to an unidirectionally rolled alloy. The high press formability of the specimen by the first cross rolling was due to a reduction in (0002) texture intensity. The high press formability of the specimen by the second cross rolling was due to not only a reduction in (0002) texture intensity but also grain refinement.