convex hull

Defect Name: convex hull (reinforcement, bulge and bulge) < br / > definition and appearance: < br / > the phenomenon of local bulge after steel strip coiling is called bulge. Slight bulge can be seen during coiling, but disappears after coiling tension is eliminated. Serious bulge has obvious bulge feel when touched by hand and obvious wave shape after opening. It mainly occurs on hot rolling mill. Once it occurs, it cannot be completely eliminated during cold rolling 。& nbsp;  & nbsp; Cause: < br / > ● axial movement of roll and abnormal crown of steel strip during rolling< Br / > ● there is linear thickening along the rolling direction of the steel strip, and when it is rolled, it shows convex hull with the continuous increase of coil diameter< Br / > ● the shape of the steel strip is poor, with large wave shape, especially the edge wave, which is easy to form convex hull defects during coiling< Br / > hazards: < br / > affect product forming and coating effect< Br / > prevention and elimination methods < br / > ● prevent roll movement and reasonably control the crown of steel strip< Br / > ● regularly change the roll and reasonably configure the roll profile to prevent the abnormal wear of the roll from causing the linear thickening of the steel strip< Br / > ● control the shape of steel strip< Br / > inspection and judgment: < br / > ● visual inspection< Br / > ● slight convex hull defects are allowed< br/>