Continuous rolling system

A continuous rolling system that changes product specifications during continuous rolling of one strip of a material to be rolled, comprising:

• a tandem rolling mill including a plurality of rolling stands, each of the plurality of rolling stands controlling a roll gap according to a roll gap operation value;
• a strip thickness gauge provided on a delivery side of the tandem rolling mill, the strip thickness gage measuring strip thickness of the material to be rolled;
• and
• a roll force distribution control device matching an actual roll force ratio between the plurality of rolling stands with a target roll force ratio;
• wherein
• the roll force distribution control device comprising:
• circuitry configured to
• determine a strip thickness target value of each of the plurality of rolling stands, and a roll force distribution ratio target value of each of the plurality of rolling stands, the roll force distribution ratio target value representing the target roll force ratio between the plurality of rolling stands,
• collect a roll force actual value of each of the plurality of rolling stands, a roll gap actual value of each of the plurality of stands, a roll rotational speed actual value of each of the plurality of rolling stands, and a strip thickness measurement value obtained by measurement with the strip thickness gauge, the roll gap actual value being calculated based on the roll gap operation value of each of the plurality of rolling stands,
• calculate a strip thickness actual value of each of the plurality of rolling stands based on the strip thickness measurement value and the roll rotational speed actual value of each of the plurality of rolling stands,
• calculate a strip thickness actual recalculation value of each of the plurality of rolling stands based on the roll force actual value of each of the plurality of rolling stands and the roll gap actual value of each of the plurality of rolling stands,
• calculate a gap error of each of the plurality of rolling stands based on a difference between the strip thickness actual value of each of the plurality of rolling stands and the strip thickness actual recalculation value of each of the plurality of rolling stands,
• calculate a gap correction value of each of the plurality of rolling stands, the gap correction value being for preventing the gap error of each of the plurality of rolling stands from being changed,
• calculate a roll force distribution ratio actual value of each of the plurality of rolling stands, the roll force distribution ratio actual value representing the actual roll force ratio between the plurality of rolling stands, based on the roll force actual value of each of the plurality of rolling stands,
• calculate a target strip thickness correction value of each of the plurality of stands based on a difference between the roll force distribution ratio target value of each of the plurality of rolling stands and the roll force distribution ratio actual value of each of the plurality of rolling stands,
• track a tracking point, the tracking point being set on the material to be rolled, and
• output the roll gap operation value to a target rolling stand when the tracking point reaches each of the plurality of rolling stands, wherein
• the rolling stand to which the tracking point reaches is set as the target rolling stand,
• the roll gap operation value is calculated to bring a difference between a first value and a second value to zero,
• the first value being obtained by correcting the strip thickness target value of the target rolling stand with the target strip thickness correction value of the target rolling stand, and
• the second value being obtained by correcting the strip thickness actual recalculation value of the target rolling stand with the gap correction value of the target rolling stand.

A roll force distribution control device comprising:

• circuitry configured to
• determine a strip thickness target value of each of a plurality of rolling stands of a tandem rolling mill, and a roll force distribution ratio target value of each of the plurality of rolling stands, each of the plurality of rolling stands controlling a roll gap according to a roll gap operation value, the roll force distribution ratio target value representing a target roll force ratio between the plurality of rolling stands,
• collect a roll force actual value of each of the plurality of rolling stands, a roll gap actual value of each of the plurality of stands, a roll rotational speed actual value of each of the plurality of rolling stands, and a strip thickness measurement value obtained by measurement with a strip thickness gauge, the strip thickness gauge being provided on a delivery side of the tandem rolling mill and measuring strip thickness of a material to be rolled, the roll gap actual value being calculated based on the roll gap operation value of each of the plurality of rolling stands,
• calculate a strip thickness actual value of each of the plurality of rolling stands based on the strip thickness measurement value and the roll rotational speed actual value of each of the plurality of rolling stands,
• calculate a strip thickness actual recalculation value of each of the plurality of rolling stands based on the roll force actual value of each of the plurality of rolling stands and the roll gap actual value of each of the plurality of rolling stands,
• calculate a gap error of each of the plurality of rolling stands based on a difference between the strip thickness actual value of each of the plurality of rolling stands and the strip thickness actual recalculation value of each of the plurality of rolling stands,
• calculate a gap correction value of each of the plurality of rolling stands, the gap correction value being for preventing the gap error of each of the plurality of rolling stands from being changed,
• calculate a roll force distribution ratio actual value of each of the plurality of rolling stands, the roll force distribution ratio actual value representing an actual roll force ratio between the plurality of rolling stands, based on the roll force actual value of each of the plurality of rolling stands,
• calculate a target strip thickness correction value of each of the plurality of stands based on a difference between the roll force distribution ratio target value of each of the plurality of rolling stands and the roll force distribution ratio actual value of each of the plurality of rolling stands,
• track a tracking point, the tracking point being set on the material to be rolled, and
• output the roll gap operation value to a target rolling stand when the tracking point reaches each of the plurality of rolling stands, wherein
• the rolling stand to which the tracking point reaches is set as the target rolling stand,
• the roll gap operation value is calculated to bring a difference between a first value and a second value to zero,
• the first value being obtained by correcting the strip thickness target value of the target rolling stand with the target strip thickness correction value of the target rolling stand, and
• the second value being obtained by correcting the strip thickness actual recalculation value of the target rolling stand with the gap correction value of the target rolling stand.