PURPOSE: To reduce thickness deviation by affixing a strain gage on the inside surface of the bar cap of a mandrel bar, receiving electric signals in accordance with the strain from the strain gage on a radio and diagnosing inconsistency between the roll center and the pass center from the variation of the strain of the bar cap.
CONSTITUTION: At least one or more strain gages 1 for measuring strain that is generated due to rolling reaction force that acts on the bar cap are affixed on the inside surface of the bar cap 6 of the mandrel bar 4. The electric signals in accordance with the strain from these strain gages are received on a radio and the variation of strain while the bar cap is revolved once during rolling is drawn on a chart. The inconsistency between the roll center and the pass center is diagnosed by grasping strain peak generation timing difference and strain peak intensity ratio based on this chart. In this way, the mandrel bar is corrected based on the data obtained from this chart, the swing phenomenon of the mandrel bar is eliminated and the generation of thickness deviation can be reduced.
YAMASHITA HAJIME
KAMINAGA IWAO
YASUOKA HIDENORI
KUWANO TAKASHI
OTSUKA TSUNEYUKI
