Finish rolling adjusting method for controlling negative tolerance of rod

The invention relates to the technical field of bar rolling, in particular to a finish rolling adjusting method for controlling the negative tolerance of a bar, which comprises the following steps: S1, inputting standard parameters; s2, acquiring dynamic parameters; s3, a finish rolling primary rack bites steel; s4, cutting the loop and lifting the loop; s5, an optical sensor monitors the sleeve height of the supplied bar; s6, if the sleeve heights of the supplied bars are consistent, the step S7 is carried out; if the sleeve heights of the supplied bars are inconsistent, the step S8 is carried out; s7, the rotating speed of the rolling mill is adjusted, and the step S9 is conducted; s8, adjusting a roll gap or a guide of the pre-cutting sortie, and carrying out the step S9; s9, if the first grating element detects the head of the bar, the step S2 is carried out; and if the first grating element does not detect the head of the bar, the step S5 is carried out. The method has the effect of improving the yield o