OPERATION CONTROL METHOD OF TANDEM ROLLING MILL, AND METHOD FOR PRODUCING HOT-ROLLED STEEL SHEET USING SAME

摘要

The present invention provide: a method of controlling operation of a tandem rolling mill which enables large reduction rolling in the latter-stage stand of the tandem rolling mill that is necessary for manufacturing fine-grained steel and the like; and a method of manufacturing a hot-rolled steel sheet. The method of controlling operation of a tandem rolling mill comprises: a first step of determining a sheet thickness on an exit side of each stand in rolling a constant portion of the material to be rolled; and a second step of determining a sheet thickness on the exit side of each stand in rolling a front end portion of the material to be rolled, such that the pre-tightening load becomes a set value or less; the material to be rolled is rolled to have the exit side sheet thickness determined in the second step, until at least the front ent portion of the material to be rolled is fed into each of the stands; the constant portion of the material to be rolled is rolled by the (N-m+1)-th stand to the N-th stand to have the exit side sheet thickness determined in the first step; and the sheet thicknesses on the exit sides of the (N-m+1)-th stand to the N-th stand determined in the second step are larger than the sheet thicknesses determined in the first step. The method of manufacturing a hot-rolled steel sheet comprises the step of rolling a steel sheet by using a row of hot finishing mills the operation of which is controlled by the above method.