Method of controlling mill pacing

A method of controlling a mill pacing in a rolling equipment wherein a plurality of rolling mills are provided downstream of a heating furnace in which a plurality of materials rest on a furnace hearth integrally moving with the materials for successively extracting said materials from said furnace, comprising the steps of:

• (a) predetermining an allowable retard period of time r.sub.x for said materials;
• (b) calculating a presupposed retard period of time h.sub.x from the following equation:
• ##EQU3## wherein MCTx(i) is a presupposed rolling cycle time (MCT) of a material i counted from the latest material to be started for rolling in a rolling mill x, T.sub.n is a target extraction time of a subsequent material n to be extracted from the heating furnace and T.sub.1 is an actual time the latest material to be started for rolling in the rolling mill x is extracted from the heating furnace;
• (c) calculating a difference f.sub.x between the predetermined allowable retard period of time r.sub.x and the presupposed retard period of time h.sub.x from the following equation:
• ##EQU4## (d) determining the maximum difference F for each of the rolling mills x from 1 to m from the following equation:
• F=MAX(f.sub.1 . . . f.sub.x . . . f.sub.m)
• (e) confirming that the allowable retard period of time r.sub.x is acceptable if F.ltoreq.0 and not acceptable if F>0;
• (f) continuing with step (g), if r.sub.x is acceptable or predetermining another allowable retard period of time r.sub.x and repeating the steps (a) through (f) if r.sub.x is not acceptable;
• (g) calculating a furnace neck extraction cycle time CT.sub.m for said particular material m from 1 to n as a function of the type of material m, a diameter D.sub.m of the material m and a length L.sub.m of the material m from the following equation:
• CT.sub.m =f(D.sub.m, L.sub.m)
• (h) determining a heating critical cycle time HCT sufficient for applying heat of a predetermined value to the material 1 to n including the subsequent material to be extracted and the latest material to be extracted from the heating furnace from the following equation:
• HCT=MAX(CT.sub.1 . . . CT.sub.m . . . CT.sub.n)
• (i) determining if the heating critical cycle time HCT is the time interval between the extraction of the subsequent material and a preceding material;
• and
• (j) extracting the material at the heating critical cycle time HCT if the heating critical cycle time is the time interval between the extraction of the subsequent material and a preceding material or predetermining another allowable retard period of time r.sub.x and repeating steps (a) through (j) if the heating critical time HCT is not said time interval.