Control method for preventing blank head obtained after shearing from being left on knife holder

The invention relates to the technical field of steel rolling automatic control, in particular to a control method for preventing a blank head obtained after shearing from being left on a knife holder. According to the technical scheme, the control method is characterized in that a steel blank is transferred through an extension roller bed and a pre-shearing roller bed after rough rolling; the head of the steel blank enters the shearing position; the extension roller bed and the pre-shearing roller bed are stopped; then, a hydraulic shearing head is started; after the steel blank is sheared, ahydraulic shear is started to lower the lower knife holder to the neutral-position position and is stopped; then, a post-shearing roller bed is started to transfer the steel blank forwards; the steelblank continues to advance towards a continuous rolling unit after pushing the head blank, obtained after shearing, away from the knife holder; and finally, the hydraulic shear is started to send thelower knife holder back to