Edge crack detection device, rolling mill facility and edge crack detection method

An edge crack detection apparatus for detecting an edge crack of a metal plate being conveyed, the edge crack detection apparatus comprising:

• a detection part including a plurality of elements arranged along a plate width direction of the metal plate, each of the plurality of elements being configured to be capable of detecting presence or absence of the metal plate at a position of the element in the plate width direction;
• a plate edge position determination part configured to determine a plate edge position of the metal plate in the plate width direction on the basis of a detection result of each of a plurality of first elements positioned within a first region in the plate width direction, from among the plurality of elements;
• and
• an edge crack detection part configured to detect an edge crack of the metal plate on the basis of a detection result of each of a plurality of second elements selected on the basis of the plate edge position and positioned within a second region which is narrower than the first region in the plate width direction, from among the plurality of elements,
• wherein the edge crack detection part is configured to determine a possibility of existence of the edge crack of the metal plate on the basis of whether the second element positioned at an inner side of the plate edge position detects absence of the metal plate, from among the plurality of second elements,
• wherein the edge crack detection apparatus includes:
• a first-end side edge crack detection part being the edge crack detection part;
• a second-end side edge crack detection part being the edge crack detection part and being disposed at an opposite side to the first-end side edge crack detection part across the metal plate in the plate width direction;
• and
• a second determination part configured to determine that the metal plate has the edge crack if, at the same time, the first-end side edge crack detection part determines that there is a possibility of the edge crack and the second element of the second-end side edge crack detection part positioned at an outer side of the plate edge position in the plate width direction does not detect presence of the metal plate.

A method of detecting an edge crack of a metal plate being conveyed, using a detection part including a plurality of elements arranged along a plate width direction of the metal plate, each of the plurality of elements being configured to be capable of detecting presence or absence of the metal plate at a position of the element in the plate width direction, the method comprising:

• a step of determining a plate edge position of the metal plate in the plate width direction on the basis of a detection result of each of a plurality of first elements positioned within a first region in the plate width direction, from among the plurality of elements;
• a step of selecting, on the basis of the determined plate edge position, a plurality of second elements positioned within a second region which is narrower than the first region in the plate width direction, from among the plurality of elements;
• and
• a step of detecting an edge crack of the metal plate on the basis of a detection result by each of the plurality of the selected second elements,
• wherein the step of detecting an edge crack of the metal plate includes determining a possibility of existence of the edge crack of the metal plate on the basis of whether the second element positioned at an inner side of the plate edge position detects absence of the metal plate, from among the plurality of second elements, and
• wherein the method comprises:
• determining a possibility of existence of the edge crack of the metal at a first position in a conveyance direction of the metal plate;
• determining a possibility of existence of the edge crack of the metal at a second position which is a position different from the first position in the conveyance direction of the metal plate;
• and
• determining that the metal plate has the edge crack if, at the same time, it is determined that there is a possibility of the edge crack at only one of the first position or the second position.