Presetting method

A presetting method of performing cold rolling using a work roll and calculating a preset value of at least one setting value of a shape control actuator included in a cold rolling mill for manufacturing a rolled stock, the presetting method comprising:

• inputting, to a model, input data including an actual value of a rolling load, the setting value, and a prediction value or an actual value of a width distribution of a thermal expansion amount at the work roll in the cold rolling performed in a past to calculate an MC actual value that is a vector in which ratios of mechanical plate crowns to a width center plate thickness at one or more width positions in the rolled stock are arranged;
• calculating, based on the MC actual value, an MC target value MC_g that is a vector in which target values of ratios of the mechanical plate crowns to the width center plate thickness at the one or more width positions P in the rolled stock to be manufactured by the cold rolling to be performed next are arranged;
• and
• selecting the setting value in the cold rolling to be performed next so that a norm of a difference Δ represented by Expression (1) is minimized, and setting the selected setting value as the preset value,
• Δ
• =
• MC_g
• -
• MC_n
• ,
• Expression
• ⁢
• (
• 1
• )
• where, MC_n in Expression (1) is a vector in which prediction values of ratios of the mechanical plate crowns to the width center plate thickness at the one or more width positions P are arranged, the vector being obtained by inputting, to the model, prediction input data including a prediction value of the rolling load in the cold rolling to be performed next, the setting value in the cold rolling to be performed next, and a prediction value or an actual value of a width distribution of a thermal expansion amount at the work roll immediately before the cold rolling to be performed next.