公开(公告)号：US11136644B2

公开(公告)日：2021-10-05

申请号：US16325299

申请日：2017-08-29

Applicant: JFE STEEL CORPORATION

Inventor： Yoshie Obata ,  Katsutoshi Takashima ,  Takashi Kobayashi ,  Hiroshi Matsuda

IPC: C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C23F17/00 ,  B32B15/01 ,  C23C2/06 ,  C22C38/60 ,  C21D8/04 ,  C22C38/18 ,  C23C2/28 ,  C23C2/40 ,  C21D1/18 ,  C21D1/25 ,  C22C18/04 ,  C25D3/22

Abstract: A high-strength cold rolled steel sheet having a specified chemical composition and a method for producing the same. The steel sheet having a microstructure including, in terms of volume fraction, 35% or less of ferrite, 1% or more and 10% or less of retained austenite, 2% or more and 12% or less of as-quenched martensite, and a total of 25% to 70% of bainite and tempered martensite. The microstructure has an average crystal grain diameter of the ferrite: 5.0 μm or less, an average crystal grain diameter of the retained austenite: 2.0 μm or less, an average crystal grain diameter of the as-quenched martensite: 3.0 μm or less, an average crystal grain diameter of the bainite and the tempered martensite phase: 4.0 μm or less, and an average intergrain distance of the as-quenched martensite of 1.0 μm or more.

公开(公告)号：US20210207234A1

公开(公告)日：2021-07-08

申请号：US16092323

申请日：2017-03-22

Applicant: JFE Steel Corporation

Inventor： Katsutoshi Takashima ,  Yoshimasa Funakawa ,  Takashi Kobayashi

IPC: C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C22C38/54 ,  C22C38/52 ,  C22C38/50 ,  C22C38/48 ,  C22C38/46 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

Abstract: A high-strength steel sheet having a chemical composition containing, by mass %, C: 0.15% to 0.25%, Si: 1.00% to 2.20%, Mn: 2.00% to 3.50%, P: 0.05% or less, S: 0.005% or less, Al: 0.01% to 0.50%, N: 0.010% or less, B: 0.0003% to 0.0050%, one, two, or more selected from Ti: 0.005% to 0.05%, Cu: 0.003% to 0.50%, Ni: 0.003% to 0.50%, Sn: 0.003% to 0.50%, Co: 0.003% to 0.05%, and Mo: 0.003% to 0.50%, and the balance being Fe and inevitable impurities and a microstructure including, in terms of volume fraction, 15% or less (including 0%) of ferrite, 2% to 15% of retained austenite, 10% or less (including 0%) of martensite, and the balance being bainite and tempered martensite, in which the average number of cementite grains having a grain diameter of 0.04 μm or more existing in the bainite and tempered martensite grains is 10 or more.

公开(公告)号：US20210054477A1

公开(公告)日：2021-02-25

申请号：US16964627

申请日：2019-01-22

Applicant: JFE Steel Corporation

Inventor： Yuka Miyamoto ,  Takashi Kobayashi ,  Yasuhiro Sakurai ,  Takeshi Yokota

IPC: C21D9/46 ,  C21D8/02 ,  C22C38/00 ,  C22C38/60 ,  C22C38/44 ,  C22C38/42 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06

Abstract: A high-carbon hot-rolled steel sheet has a composition containing, on a percent by mass basis, C: 0.10% or more and less than 0.20%, Si: 0.5% or less, Mn: 0.25% to 0.65%, P: 0.03% or less, S: 0.010% or less, sol. Al: 0.10% or less, N: 0.0065% or less, Cr: 0.05% to 0.50%, and B: 0.0005% to 0.005%, the balance being Fe and incidental impurities, the high-carbon hot-rolled steel sheet having a microstructure containing ferrite and cementite, in which the percentage of the number of cementite grains having an equivalent circular diameter of 0.1 μm or less is 12% or less based on the total number of cementite grains, the amount of Cr dissolved in the steel sheet is 0.03% to 0.50%, and the high-carbon hot-rolled steel sheet has a hardness of 73 or less in terms of HRB and a total elongation of 37% or more.

公开(公告)号：US10400298B2

公开(公告)日：2019-09-03

申请号：US14903842

申请日：2014-07-08

Applicant: JFE STEEL CORPORATION

Inventor： Yuka Miyamoto ,  Takashi Kobayashi ,  Chikara Kami ,  Hayato Saito ,  Kaneharu Okuda

IPC: C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/60 ,  C21D1/26 ,  C21D6/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C21D1/74 ,  C21D1/32

Abstract: There is provided is a high-carbon hot-rolled steel sheet and method for producing the same. The steel sheet has excellent hardenability consistently, even when annealed in a nitrogen atmosphere, and excellent formability. The steel sheet has a hardness in the range of 83 HRB or less and a total elongation of 30% or more before being subjected to a quenching treatment.

公开(公告)号：US10323293B2

公开(公告)日：2019-06-18

申请号：US14370121

申请日：2012-12-25

Applicant: JFE STEEL CORPORATION

Inventor： Yuka Miyamoto ,  Takashi Kobayashi ,  Nobuyuki Nakamura ,  Yoshimasa Funakawa

IPC: C21D9/46 ,  B21B3/00 ,  C22C38/00 ,  C22C38/06 ,  C22C38/60 ,  C22C38/02 ,  C22C38/04 ,  C21D6/00 ,  C21D8/02 ,  C22C38/08 ,  C22C38/22 ,  C22C38/32 ,  B22D11/12 ,  C21D1/26

Abstract: A high-carbon hot rolled steel sheet with excellent hardenability and small in-plane anisotropy, and a method for manufacturing the steel sheet are provided. The steel sheet has a chemical composition including, by mass %, C: 0.20 to 0.48%, Si: not more than 0.1%, Mn: not more than 0.5%, P: not more than 0.03%, S: not more than 0.01%, sol. Al: not more than 0.10%, N: not more than 0.005% and B: 0.0005 to 0.0050%, the balance including Fe and inevitable impurities. The steel sheet includes a microstructure containing ferrite and cementite. The cementite has an average grain size of not more than 1.0 μm. The steel sheet has an in-plane anisotropy of r value, Δr, of not more than 0.1 in absolute value.

公开(公告)号：US20160032431A1

公开(公告)日：2016-02-04

申请号：US14781440

申请日：2014-03-20

Applicant: JFE STEEL CORPORATION

Inventor： Takashi Kobayashi ,  Hayato Saito ,  Yoshimasa Funakawa

IPC: C22C38/38 ,  C21D9/46 ,  C21D6/00 ,  C22C38/28 ,  C22C38/00 ,  C22C38/24 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C21D8/02 ,  C22C38/26

CPC classification number: C22C38/38 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0226 ,  C21D8/0263 ,  C21D9/46 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/009 ,  C22C38/00 ,  C22C38/001 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/36 ,  C23C8/26 ,  C23C8/32

Abstract: A steel sheet for nitriding has excellent formability and punchability. The steel sheet has a composition including, in percent by mass, 0.02% to 0.08% of C, 0.1% or less of Si, 0.2% to 1.8% of Mn, 0.05% or less of P, 0.02% or less of S, 0.01% to 0.06% of Al, 0.5% to 1.5% of Cr, 0.01% or less of N, and the balance being Fe and incidental impurities; and has a microstructure including ferrite as a main phase and pearlite and/or bainite as a secondary phase. The ferrite has a fraction of 70% or more in the entire microstructure and an average grain diameter of 5 to 25 gm. An average length of the major axis of cementite present in the secondary phase in a cross section in the rolling direction of the steel sheet is 3.0 μm or less.

Abstract translation: 用于氮化的钢板具有优异的成形性和冲压性。 该钢板的组成按质量计含有C：0.02〜0.08％，Si：0.1％以下，Mn：0.2〜1.8％，P：0.05％以下，S：0.02％ 0.01％〜0.06％的Al，0.5〜1.5％的Cr，0.01％以下的N，余量为Fe和杂质; 并且具有包含铁素体作为主相的组织，珠光体和/或贝氏体作为第二相。 铁素体在整个微观结构中的分数为70％以上，平均粒径为5〜25gm。 在钢板的轧制方向的截面中，次级相中存在的渗碳体的长轴的平均长度为3.0μm以下。

公开(公告)号：US20150090376A1

公开(公告)日：2015-04-02

申请号：US14370314

申请日：2012-12-26

Applicant: JFE STEEL CORPORATION

Inventor： Nobuyuki Nakamura ,  Takashi Kobayashi ,  Yoshimasa Funakawa

IPC: C22C38/60 ,  C21D9/46 ,  C21D1/26 ,  C22C38/54 ,  C22C38/32 ,  C22C38/00 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C21D8/02 ,  C22C38/16

CPC classification number: C22C38/60 ,  C21D1/26 ,  C21D1/32 ,  C21D8/0226 ,  C21D8/0263 ,  C21D9/46 ,  C21D2211/003 ,  C21D2211/005 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/16 ,  C22C38/18 ,  C22C38/32 ,  C22C38/54 ,  Y02P10/212

Abstract: A high carbon hot rolled steel sheet and a method for manufacturing the same are provided, wherein excellent cold workability and excellent hardenability are obtained stably. The high carbon hot rolled steel sheet has a composition containing C: 0.20% to 0.48%, Si: 0.1% or less, Mn: 0.5% or less, P: 0.03% or less, S: 0.01% or less, sol. Al: more than 0.10% and 1.0% or less, N: 0.005% or less, B: 0.0005% to 0.0050%, and the remainder composed of Fe and incidental impurities, on a percent by mass basis, and a microstructure composed of ferrite and cementite, wherein the average grain size of the above-described ferrite is 10 to 20 μm and the spheroidization ratio of the above-described cementite is 90% or more.

Abstract translation: 提供一种高碳热轧钢板及其制造方法，其中稳定地获得优异的冷加工性和优异的淬透性。 高碳热轧钢板具有C：0.20〜0.48％，Si：0.1％以下，Mn：0.5％以下，P：0.03％以下，S：0.01％以下的组成。 Al：0.10质量％以上且1.0％以下，N：0.005％以下，B：0.0005％〜0.0050％，余量由Fe和杂质构成，以质量计，由铁素体构成的组织 和渗碳体，其中上述铁素体的平均粒径为10〜20μm，上述渗碳体的球化率为90％以上。