| 摘要 |
PURPOSE:To decide as to whether or not the insertion of a bar is normal with the red color area ratio of each window, by observing the image of the shell of the time when a mandrel bar is inserted to the shell prior to rolling from the plural windows provided in the axial direction of the shell. CONSTITUTION:The image of a shell by an ITV camera is observed through plural windows 4, 5, 6. At this time, it is decided as to whether or not a mandrel bar is normally inserted to a shell 12 with the red color area ratio of the visual field of the window 4, 5, 6 because of the shell 12 being red-heated. In the case of the shell 12 being displaced with its bent or misregistration provisionally, the red color area ratio of the visual field of the window 6 is largely reduced because of the shell 12 hardly existing in the visual field of the window 6. It can therefore be decided that the insertion of the mandrel bar is defective. |
