Control device for rolling mill apparatus, rolling mill facility, and operation method for rolling mill apparatus

A control device for a rolling mill apparatus including at least one rolling mill stand for rolling a metal plate, the control device including:

• a detection signal acquisition part for receiving, from an edge crack sensor, a detection signal of an edge crack at an end portion of the metal plate in a plate width direction;
• and
• a rolling condition decision part for deciding a rolling condition for the rolling mill apparatus,
• wherein the rolling condition decision part is configured to change, if the detection signal acquisition part receives the detection signal of the edge crack, the rolling condition for the rolling mill apparatus from a first rolling condition immediately before detection of the edge crack to a second rolling condition which is more capable of suppressing growth of the edge crack than the first rolling condition,
• wherein the at least one rolling mill stand includes an upstream-side stand disposed at an upstream side of a detection position of the edge crack in an advance direction of the metal plate,
• wherein the at least one rolling mill stand includes a downstream-side stand disposed at a downstream side of the detection position of the edge crack in the advance direction, and
• wherein the rolling condition decision part is configured to, during operation of the rolling mill apparatus under the second rolling condition:
• reduce a tension of an end portion of the metal plate in the plate width direction in a region between the upstream-side stand and the downstream-side stand to be smaller than the tension under the first rolling condition until the edge crack passes through the downstream side stand;
• and
• set the tension in the region back to the tension under the first rolling condition after the edge crack passes through the downstream-side stand.

A method of operating a rolling mill apparatus including at least one rolling mill stand, the method comprising:

• a step of rolling a metal plate using the rolling mill apparatus;
• a step of detecting an edge crack at an end portion of the metal plate in a plate width direction during rolling by the rolling mill apparatus;
• and
• a step of changing, if the edge crack of the metal plate is detected, a rolling condition for the rolling mill apparatus from a first rolling condition immediately before detection of the edge crack to a second rolling condition which is more capable of suppressing growth of the edge crack than the first rolling condition,
• wherein the at least one rolling mill stand includes an upstream-side stand disposed at an upstream side of a detection position of the edge crack in an advance direction of the metal plate, and
• wherein the at least one rolling mill stand includes a downstream-side stand disposed at a downstream side of the detection position of the edge crack in the advance direction, and
• wherein the method comprises a step of, during operation of the rolling mill apparatus under the second rolling condition,
• reducing a tension of an end portion of the metal plate in the plate width direction in a region between the upstream-side stand and the downstream-side stand to be smaller than the tension under the first rolling condition until the edge crack passes through the downstream side stand, and
• setting the tension in the region back to the tension under the first rolling condition after the edge crack passes through the downstream-side stand.