Nippon Steel Nisshin Co., Ltd.

Ns Wheeling-Nisshin, Inc.

Kazuhiro Yamada

Shinya Furukawa

Yasunori Hattori

Shinichi Koga

Koutarou Ishii

Patrick Edward Pendleton

A hot-dip coating equipment includes a cooling rate determining device that includes: a coefficient obtaining section configured to obtain coefficients &#x3b1;, &#x3b2;, &#x3b3;, and &#x3b4; 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 =(&#x3b1;&#xd7;[SE]+&#x3b2;)&#xd7;{(T&#x2212;ST)/A}+&#x3b3;&#xd7;[SE]+&#x3b4; . . . (1), where: [SE] is a concentration (mass %) of a specific element contained in the hot-dip coating bath; T is a temperature (&#xb0; C.) of the hot-dip coating bath; and ST is a solidification temperature (&#xb0; C.) at which the hot-dip coating bath is solidified.

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Follansbee, WV, United States of America

Kazuhiro Yamada