THICKNESS CONTROLLING METHOD FOR TUBE ROLLING MILL

PURPOSE:To enable rapid response to change of setting by making thickness setting change control by making time for changing setting and the distance necessary for changing setting evaluation functions in a optimum formula model in setting roll gap and plug position and making thickness setting change control. CONSTITUTION:In rolling a material 3 to a seamless tube by a pair of working rolls 1 of inclination beta and a plug 2 of outer diameter DP, gorge E and lead L are controlled by devices 30, 4 according to respective setting values. The relation between E and L when the thickness of the tube is tA, tB is m, n, and when tA tB, minimum distance is obtained by correcting E and L in point A B. The device 10 stores specifications 10a, 10b, and a thickness calculating device 9 determines t from a load P of a detector 5 by formulaI(LP: length of inclined part of a plug, K: coefficient of rigidity of rolling mill). Gorge, lead calculating devices 7, 8 determine target values EB, LB by formulae II, III respectively, and control the devices 30, 4 after correcting if necessary.