Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 09, 2018 - September 12, 2018
An unequal diameter twin roll caster is a device capable of casting a strip by pouring molten metal between two pairs of rolls having different diameters. Ripple marks, which are typical surface defects of twin rolls, are required to be suppressed because they lower the corrosion resistance of the final product. In general, ripple marks are prominent in Al-Mg alloys. In this study, we investigated the conditions to reduce the ripple mark using an unequal diameter twin roll caster. We used AC7A for the experiment. The ripple mark is considered to be caused by meniscuses between the back dam and the lower roll. A meniscus forms between the back dam and the lower roll, and that part is the lower roll and cooled by the upper roll. By repeating this process, the ripple marks are considered to be formed. The result of our experiment showed that the ripple mark were reduced at the slow roll speed even at the same solidification distance. From these results, it has been found that it is effective to lengthen the coagulation time to suppress the ripple marks.
