Rolling control device, rolling control method, and program

A rolling control method that derives a preset load value in order to bring an elongation rate of a metal sheet to a target value or within a target range after a welded portion of the metal sheet passes through a temper rolling mill while rolling is suspended or under soft reduction, and outputs a reduction command based on the preset load value with a computer, wherein, the computer executes:

• a first preset load updating step that derives an updated value of the preset load based on operation actual result values during a first period from a first timing to a second timing;
• an evaluation index deriving step that derives an evaluation index of the difference between a plasticity coefficient of the metal sheet during the first period and a plasticity coefficient of the metal sheet during a second period from the second timing to a third timing;
• a determining step that determines whether or not the updated value of the preset load derived by the first preset load updating step needs to be updated again based on the evaluation index derived by the evaluation index deriving step;
• a second preset load updating step that derives a re-updated value of the preset load based on operation actual result values during the second period when the determining step determines that the updated value of the preset load derived by the first preset load updating step needs to be updated again;
• a first plasticity deriving step that derives first plasticity coefficient of the metal sheet based on operation actual result values at the first timing and operation actual result values at the second timing;
• and
• a second deriving step that derives a second plasticity coefficient of the metal sheet or a physical quantity that is correlated with a plasticity coefficient of the metal sheet based on the operation actual result values at the second timing and operation actual result values at the third timing, wherein
• the preset load is a rolling load to be preset as a target rolling load of the temper rolling mill,
• the first timing is a timing before a timing when a measured value of a rolling load at the temper rolling mill becomes the preset load,
• the second timing is a timing when the measured value of the rolling load at the temper rolling mill has become the preset load,
• the third timing is a timing before the measured value of the rolling load at the temper rolling mill becomes the updated value of the preset load derived by the first preset load updating step, and
• the evaluation index is an index determined based on the first plasticity coefficient and the second plasticity coefficient or the physical quanitiy.

A non-transitory computer readable medium storing a program causing a computer to execute pieces of processing intended for deriving a preset load value in order to bring an elongation rate of a metal sheet to a target value or within a target range after a welded portion of the metal sheet passes through a temper rolling mill while rolling is suspended or under soft reduction, and outputting a reduction command based on the preset load value, the program causing a computer to execute:

• a first preset load updating step that derives an updated value of the preset load based on operation actual result values during a first period from a first timing to a second timing;
• an evaluation index deriving step that derives an evaluation index of the difference between a plasticity coefficient of the metal sheet during the first period and a plasticity coefficient of the metal sheet during a second period from the second timing to a third timing;
• a determining step that determines whether or not the updated value of the preset load derived by the first preset load updating step needs to be updated again based on the evaluation index derived by the evaluation index deriving step;
• a second preset load updating step that derives a re-updated value of the preset load based on operation actual result values during the second period when the determining step determines that the updated value of the preset load derived by the first preset load updating step needs to be updated again;
• a first plasticity deriving step that derives a first plasticity coefficient of the metal sheet based on operation actual result values at the first timing and operation actual result values at the second timing:
• and
• a second deriving step that derives a second plasticity coefficient of the metal sheet or a physical quantity that is correlated with a plasticity coefficient of the metal sheet based on the operation actual result values at the second timing and operation actual result values at the third timing, wherein
• the preset load is a rolling load to be preset as a target rolling load of the temper rolling mill,
• the first timing is a timing before a timing when a measured value of a rolling load at the temper rolling mill becomes the preset load,
• the second timing is a timing when the measured value of the rolling load at the temper rolling mill has become the preset load,
• the third timing is a timing before the measured value of the rolling load at the temper rolling mill becomes the updated value of the preset load derived by the first preset load updating step, and
• the evaluation index is an index determined based on the first plasticity coefficient and the second plasticity coefficient of the physical quantity.