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: A method of pretreating and hot-dip coating aluminum or aluminum alloys on a chromium-containing steel strip to provide an improved coating comprising annealing final gauge steel strip in an oxygen excess atmosphere to produce a chromium-rich oxide on the surface and thereafter electrolytically descaling the strip in an aqueous salt solution to remove the oxide and to expose a chromium depleted surface of the strip. The strip is then transported to a coating line where it is heated to a temperature at or above the temperature of a bath of aluminum or aluminum alloy. A substantially hydrogen atmosphere is maintained over the bath while the dew point is maintained below minus 35.degree. C. The strip is then drawn through the bath to coat the strip.