Nippon Steel Corporation

Tatsuya Nakada

Satoshi Uchida

Yuji Yamaguchi

Atsushi Morishita

Taihei Kaneto

Tetsuo Kishimoto

Naoki Kataoka

Yoji Nakamura

Satoru Mashiko

Akihisa Tsuruta

Toshiaki Saitoh

In a thickness range of which center is a &#xbc; thickness from the surface of a base steel sheet, a volume fraction of a ferrite phase is 0% to less than 50%, a volume fraction of the total of a hard structure composed of one or more of a bainite structure, a bainitic ferrite phase, a fresh martensite phase, and a tempered martensite phase is 50% or more, a volume fraction of a retained austenite phase is 0-8%, and a volume fraction of the total of a pearlite phase and a coarse cementite phase is 0-8%, at an interface between a plating layer and the base steel sheet, a Fe&#x2014;Al alloy layer is provided, the Fe&#x2014;Al alloy layer having an average thickness of 0.1-2.0 &#x3bc;m and a difference between a maximum thickness and a minimum thickness in the width direction of the steel sheet being within 0.5 &#x3bc;m.

Hot-dip galvanized steel sheet

A hot-dip galvanized steel sheet including: a hot-dip galvanizing layer on at least one side of a base steel sheet. The hot-dip galvanizing layer has a Fe content of more than 0% to 3.0% and an Al content of more than 0% to 1.0%. The hot-dip galvanized steel sheet includes a Fe&#x2014;Al alloy layer provided on an interface between the hot-dip galvanizing layer and the base steel sheet and a fine-grain layer provided in the base steel sheet and directly in contact with the Fe&#x2014;Al alloy layer. The Fe&#x2014;Al alloy layer has a thickness of 0.1-2.0 &#x3bc;m. The fine-grain layer has an average thickness of 0.1-5.0 &#x3bc;m, includes a ferrite phase with an average grain diameter of 0.1-3.0 &#x3bc;m, and contains oxides of one or more out of Si and Mn, a maximum diameter of the oxides being 0.01-0.4 &#x3bc;m.

There is provided a hot-dip galvanized steel sheet with a microstructure in a &#x215b; thickness to &#x215c; thickness range whose middle is a &#xbc; thickness from a surface of a base steel sheet, the microstructure contains ferrite phase is 50% or more and 97% or less by volume fraction, and a predetermined phase wherein at an interface between a hot-dip galvanizing layer and the base steel sheet, a Fe&#x2014;Al alloy layer has an average thickness of 0.1 &#x3bc;m to 2.0 &#x3bc;m, and a difference between a maximum thickness and a minimum thickness in a steel sheet width direction is within 0.5 &#x3bc;m, and in a fine-grain layer directly brought into contact with the Fe&#x2014;Al alloy layer, the fine-grain has a difference between a maximum thickness and a minimum thickness of the fine-grain layer in the steel sheet width direction is within 2.0 &#x3bc;m.

An edging method including changing an incident angle of a slab with respect to a pair of edging members that are disposed on a conveyance line of the slab and that edge the slab based on information relating to the slab acquired at at least one of prior to edging or after edging.

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Tokyo, Japan

Tatsuya Nakada