公开(公告)号：US20200232083A1

公开(公告)日：2020-07-23

申请号：US16633529

申请日：2017-07-31

Applicant: NIPPON STEEL CORPORATION

Inventor： Atsushi MORISHITA ,  Taihei KANETO ,  Satoshi UCHIDA ,  Tatsuya NAKADA ,  Yuji YAMAGUCHI

IPC: C23C2/06 ,  B32B15/01 ,  C21D9/48 ,  C21D8/04 ,  C21D6/00 ,  C23C2/40 ,  C23C2/02 ,  C22C38/06 ,  C22C38/04 ,  C22C38/00 ,  C22C38/02

Abstract: A hot-dip galvanized steel sheet including: a hot-dip galvanizing layer on at least one side of a base steel sheet, wherein the hot-dip galvanizing layer has a Fe content of more than 0% and 3.0% or less and an Al content of more than 0% and 1.0% or less, the hot-dip galvanized steel sheet including: a Fe—Al alloy layer provided on an interface between the hot-dip galvanizing layer and the base steel sheet, the Fe—Al alloy layer having a thickness of 0.1 μm to 2.0 μm, and a difference between a maximum value and a minimum value of the thickness of the Fe—Al alloy layer in a width direction of the base steel sheet being within 0.5 μm; and a fine-grain layer provided in the base steel sheet and directly in contact with the Fe—Al alloy layer, the fine-grain layer having an average thickness of 0.1 μm to 5.0 μm, the fine-grain layer including a ferrite phase with an average grain diameter of 0.1 μm to 3.0 μm, the fine-grain layer containing oxides of one or more out of Si and Mn, a maximum diameter of the oxides being 0.01 μm to 0.4 μm, and a difference between a maximum value and a minimum value of the thickness of the fine-grain layer in the width direction of the base steel sheet being within 2.0 μm.

公开(公告)号：US20200230918A1

公开(公告)日：2020-07-23

申请号：US16635499

申请日：2017-07-31

Applicant: NIPPON STEEL CORPORATION

Inventor： Atsushi MORISHITA ,  Taihei KANETO ,  Satoshi UCHIDA ,  Tatsuya NAKADA ,  Yuji YAMAGUCHI

IPC: B32B15/01 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/22 ,  C22C38/16 ,  C22C38/08 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C23C2/06 ,  C23C2/40

Abstract: In a specific thickness range of which center is a ¼ thickness from the surface of a base steel sheet, a volume fraction of a ferrite phase is 0% or more and 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% to 8%, and a volume fraction of the total of a pearlite phase and a coarse cementite phase is 0% to 8%, at an interface between a plating layer and the base steel sheet, a Fe—Al alloy layer is provided, the Fe—Al alloy layer having an average thickness of 0.1 μm to 2.0 μm and a difference between a maximum thickness and a minimum thickness in the width direction of the steel sheet being within 0.5 μm, and in a fine-grain layer directly in contact with the Fe—Al alloy layer, the difference between a maximum thickness and a minimum thickness of the fine-grain layer in the width direction of the steel sheet is within 2.0 μm.

公开(公告)号：US20200156349A1

公开(公告)日：2020-05-21

申请号：US16635511

申请日：2017-07-31

Applicant: NIPPON STEEL CORPORATION

Inventor： Atsushi MORISHITA ,  Taihei KANETO ,  Satoshi UCHIDA ,  Tatsuya NAKADA ,  Yuji YAMAGUCHI

IPC: B32B15/01 ,  C22C38/28 ,  C21D9/46 ,  C22C38/38 ,  C21D6/00 ,  C22C38/26 ,  C22C38/02 ,  C22C38/00 ,  C22C38/22 ,  C22C38/08 ,  C22C38/32 ,  C21D8/02 ,  C22C38/16 ,  C22C38/06

Abstract: There is provided a hot-dip galvanized steel sheet with a microstructure in a ⅛ thickness to ⅜ thickness range whose middle is a ¼ 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—Al alloy layer has an average thickness of 0.1 μm to 2.0 μm, and a difference between a maximum thickness and a minimum thickness in a steel sheet width direction is within 0.5 μm, and in a fine-grain layer directly brought into contact with the Fe—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 μm.