Steel-sheet non-plating defect prediction method, steel-sheet defect reduction method, hot-dip galvanized steel sheet manufacturing method, and steel-sheet non-plating defect prediction model generation method

A manufacturing method of a hot-dip galvanized steel sheet manufactured in manufacturing equipment of the hot-dip galvanized steel sheet, the manufacturing equipment including an annealing furnace and a plating device arranged on a downstream side of the annealing furnace, wherein the hot-dip galvanized steel sheet uses a high-tensile steel sheet as a base material, the method comprising:

• performing a steel-sheet defect reduction that includes:
• predicting non-plating defect information of a steel sheet by predicting a steel-sheet non-plating defect by using attribute information of the steel sheet, result values of operational parameters of the annealing furnace, and set values of the operational parameters of the plating device before a tip portion of the steel sheet is charged into the plating device, wherein the predicting the steel-sheet non-plating defect includes predicting steel-sheet non-plating defect information on an exit side of the manufacturing equipment by using a non-plating defect prediction model which is learned by machine learning, the non-plating defect prediction model for which:
• an input data is data including one or two or more parameters selected from attribute information of the steel sheet charged into the manufacturing equipment, one or two or more operational parameters selected from operational parameters of the annealing furnace, and one or two or more operational parameters selected from operational parameters of the plating device, and
• an output data is the non-plating defect information of the steel sheet on the exit side of the manufacturing equipment in order to control an operation of the manufacturing equipment;
• and
• resetting the operational parameters of the plating device in such a manner that a non-plating defect generation rate according to the predicted non-plating defect information of the steel sheet is within a preset allowable range;
• and
• manufacturing the hot-dip galvanized steel sheet in the manufacturing equipment by using the steel-sheet defect reduction,
• wherein the plating device is a plating device in which a snout, a plating bath, and a wiping nozzle are arranged in this order from the upstream side, and a temperature of the plating bath and a temperature of the steel sheet entering the plating bath are included as the operational parameters of the plating device which parameters are included in the input data.