Incoming materials The incoming materials have serious quality defects, such as waste edge pressing, overflow edge, under-pickling, over-pickling, uneven thickness, plate-shaped edge waves and middle waves, etc., which may cause belt breakage. 2. Equipment failure Electrical, control system failure or hydraulic system failure. The common ones are tension fluctuation, tension disappearance, hydraulic system, emulsion system shutdown, etc. 3. Operation failure The belt breakage caused by the operation accident is more common. The deviation of the strip and the defects of incoming materials were not detected and taken measures in time; the selection of the pass plan was unreasonable, the deformation of the pass was too large, the rolling pressure was large, and the shape of the plate was difficult to control; the tension before and after the pass was too large and the strip was broken. ; The thickness fluctuates somewhere in the previous pass, and the current pass has not been adjusted and decelerated in time. 4. Belt breakage caused by roll burst