Abstract: Provided is a hot-dip aluminized steel sheet with fine-sized spangles produced in a different way from conventional methods, and a method of producing a hot-dip aluminized steel sheet with fine-sized spangles in a different way from conventional methods. The hot-dip aluminized steel sheet includes: a substrate steel sheet; and an aluminum-based coating which is formed by a hot-dip method on the surface of the substrate steel sheet and in which the average B concentration is not less than 0.005 mass % and the sum of the average Ti concentration and the average V concentration is not more than 0.03 mass %.

Abstract: A hot-dip coating equipment includes a cooling rate determining device that includes: a coefficient obtaining section configured to obtain coefficients ?, ?, ?, and ? associated with the hot-dip coating bath, in the following equation that expresses a degree of discoloration YI of the surface of a hot-dip coated steel sheet; and a rate determining section configured to determine an average cooling rate A so as to allow the YI of the following Expression (1) to be not more than a predetermined reference value, YI =(?×[SE]+?)×{(T?ST)/A}1/2+?×[SE]+? . . . (1), where: [SE] is a concentration (mass %) of a specific element contained in the hot-dip coating bath; T is a temperature (° C.) of the hot-dip coating bath; and ST is a solidification temperature (° C.) at which the hot-dip coating bath is solidified.

Abstract: Provided is a hot-dip aluminized steel sheet with fine-sized spangles produced in a different way from conventional methods, and a method of producing a hot-dip aluminized steel sheet with fine-sized spangles in a different way from conventional methods. The hot-dip aluminized steel sheet includes: a substrate steel sheet; and an aluminum-based coating which is formed by a hot-dip method on the surface of the substrate steel sheet and in which the average B concentration is not less than 0.005 mass % and the sum of the average Ti concentration and the average V concentration is not more than 0.03 mass %.

Abstract: A problem to be solved by the present invention is to prevent discoloration of a surface of a hot-dip coated steel sheet after hot-dip coating. A cooling rate determining device includes: a coefficient obtaining section configured to obtain coefficients ?, ?, ?, and ? associated with the hot-dip coating bath, in the following Expression (1) which expresses a degree of discoloration YI of the surface of a hot-dip coated steel sheet; and a rate determining section configured to determine an average cooling rate A so as to allow the YI of the following Expression (1) to be not more than a predetermined reference value, YI=(?×[SE]+?)×{(T?ST)/A}1/2+?×[SE]+???(1), where: [SE] is a concentration (mass %) of a specific element contained in the hot-dip coating bath; T is a temperature (° C.) of the hot-dip coating bath; and ST is a solidification temperature (° C.) at which the hot-dip coating bath is solidified.