公开(公告)号：US12065711B2

公开(公告)日：2024-08-20

申请号：US17262884

申请日：2019-06-10

Applicant: JFE Steel Corporation

Inventor： Kazuhiko Yamazaki ,  Takeshi Yokota ,  Sumio Kaiho ,  Noriaki Moriyasu

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

CPC classification number: C21D9/46 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/005 ,  C21D8/0226 ,  C21D8/0263 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/06 ,  C22C38/08 ,  C22C38/16 ,  C22C38/22 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C21D2211/002 ,  C21D2211/008

Abstract: A high-strength hot rolled steel sheet and a method for manufacturing the high-strength hot rolled steel sheet are disclosed. The high-strength hot rolled steel sheet includes a specific chemical composition, and a steel structure in which a lower bainite phase and/or a tempered martensite phase at 90% or more in terms of a total area fraction is contained as a dominant phase, an average grain size of the dominant phase is 10.0 μm or less, and an amount of Fe in Fe-based precipitates is 0.70% or less in mass %, in which an arithmetic average roughness (Ra) of a surface is 2.50 μm or less, and a tensile strength TS is 1180 MPa or more.

公开(公告)号：US11578375B2

公开(公告)日：2023-02-14

申请号：US15747583

申请日：2016-07-20

Applicant: JFE STEEL CORPORATION

Inventor： Kazuhiko Yamazaki ,  Shunsuke Toyoda ,  Noriaki Moriyasu ,  Kentaro Irisa

IPC: C21D8/02 ,  C21D9/46 ,  C22C38/38 ,  C22C38/00 ,  C22C38/06 ,  C22C38/28 ,  C22C38/32 ,  C22C38/60 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/02 ,  C22C38/40 ,  C22C38/04 ,  C22C38/34

Abstract: A high-strength hot-rolled steel sheet that has excellent punching workability and hole expandability, and a method for manufacturing the same. The hot-rolled steel sheet has a tensile strength of 980 MPa or more. The hot-rolled steel sheet has a chemical composition containing C, Si, Mn, P, S, Al, N, Ti, Cr, and B, and has a microstructure including a bainite phase having an area ratio of 85% or more as a main phase, and a martensite phase or martensite-austenite constituent having an area ratio of 15% or less as a second phase, the balance being a ferrite phase. The second phase has an average grain diameter of 3.0 μm or less, prior-austenite grains have an average aspect ratio of 1.3 or more and 5.0 or less, and recrystallized prior-austenite grains have an area ratio of 15% or less relative to non-recrystallized prior-austenite grains.

公开(公告)号：US20160068937A1

公开(公告)日：2016-03-10

申请号：US14784450

申请日：2014-03-17

Applicant: JFE STEEL CORPORATION

Inventor： Katsumi Nakajima ,  Kazuhiko Yamazaki ,  Chikara Kami

IPC: C22C38/58 ,  C23C2/02 ,  C21D6/00 ,  C21D8/02 ,  C22C38/50 ,  C22C38/46 ,  C22C38/44 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/24 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  B32B15/01 ,  C23C2/40

CPC classification number: C21D1/20 ,  B21D22/022 ,  B32B15/013 ,  C21D1/84 ,  C21D6/004 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0263 ,  C21D8/0426 ,  C21D8/0463 ,  C21D9/46 ,  C21D2211/002 ,  C21D2211/003 ,  C22C18/04 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/18 ,  C22C38/24 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C22C38/58 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C23F17/00

Abstract: A steel slab having a composition containing C: more than 0.07% and 0.2% or less, Si: 2.0% or less, Mn: 1.0% to 3.0%, Al: 0.1% or less, Ti: 0.05% to 0.3%, and V: 0.05% to 0.3% on a mass percent basis is heated to 1100° C. or more and is subjected to rough rolling and finish rolling. In the finish rolling, the total rolling reduction of two final passes is 30% or more, and the finish rolling temperature ranges from (Ar3 transformation temperature) to (Ar3 transformation temperature+120° C.). Cooling is started within 2 seconds after the finish rolling. Coiling is performed at an average cooling rate of 40° C./s or more at a coiling temperature in the range of 300° C. to 500° C. The resulting high-strength hot-rolled steel sheet has a microstructure in which a bainite phase constitutes more than 90% by volume, the average lath interval of bainite is 0.45 μm or less, and the ratio of Fe-based carbide precipitated in bainite lath to all Fe-based carbide is 10% or more, has a high tensile strength of 900 MPa or more, and has significantly improved punchability in mass production.

Abstract translation: 具有C：大于0.07％和0.2％以下，Si：2.0％以下，Mn：1.0％〜3.0％，Al：0.1％以下，Ti：0.05〜0.3％的组成的钢坯，以及 V：以质量％计为0.05〜0.3％，加热至1100℃以上，进行粗轧，精轧。 在精轧中，两次最终道次的总压下率为30％以上，精轧温度为（Ar3相变温度）〜（Ar3相变温度+ 120℃）。 精轧后2秒内开始冷却。 在卷取温度为300℃〜500℃的范围内，以40℃/ s以上的平均冷却速度进行卷取。所得到的高强度热轧钢板具有微观结构，其中， 贝氏体相构成体积的90％以上，贝氏体的平均板条间隔为0.45μm以下，贝氏体板条中析出的Fe系碳化物与全部Fe系碳化物的比例为10％以上，具有高的拉伸强度 强度为900MPa以上，并且在批量生产中具有显着提高的冲压性。

公开(公告)号：US11732340B2

公开(公告)日：2023-08-22

申请号：US17262975

申请日：2019-06-10

Applicant: JFE Steel Corporation

Inventor： Sota Goto ,  Kazuhiko Yamazaki ,  Thi Huyen Doan ,  Yoshihiko Ono

IPC: C22C38/60 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/22 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  B32B15/01 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C21D8/04 ,  C22C38/50 ,  B32B15/04 ,  C23C30/00 ,  B32B15/18

CPC classification number: C22C38/60 ,  B32B15/012 ,  B32B15/013 ,  B32B15/04 ,  B32B15/043 ,  B32B15/18 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0263 ,  C21D8/0278 ,  C21D8/0426 ,  C21D8/0463 ,  C21D8/0478 ,  C21D9/46 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/22 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C22C38/50 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C23C30/00 ,  C23C30/005 ,  C21D2211/002 ,  C21D2211/008 ,  Y10T428/12757 ,  Y10T428/12799 ,  Y10T428/12958

Abstract: Provided is a high-strength hot-rolled coated steel sheet having a TS of 980 MPa or more, excellent bulging formability and stretch flange formability, and excellent coatability.
The high-strength hot-rolled coated steel sheet includes a steel sheet having a chemical composition containing, by mass %, C: 0.03% to 0.09%, Si: 0.01% to 1.60%, Mn: 2.20% to 3.60%, P: 0.100% or less, S: 0.0100% or less, Ti: 0.05% to 0.18%, B: 0.0005% to 0.0050%, Al: 0.005% to 0.40%, N: 0.010% or less, and a balance of Fe and inevitable impurities, in which a CSM value expressed by the equation 33.8[% C][% Mn]+12.4[% Si]/[% Mn] is 3.3 to 12.0, and a steel microstructure containing bainite in an amount of 85% or more in terms of area fraction and martensite in an amount of 2.0% or more and 15.0% or less in terms of area fraction and includes a coating layer or an alloyed coating layer on a surface of the steel sheet.

公开(公告)号：US11345972B2

公开(公告)日：2022-05-31

申请号：US15121159

申请日：2015-02-17

Applicant: JFE STEEL CORPORATION

Inventor： Kazuhiko Yamazaki ,  Kaneharu Okuda

IPC: C21D9/46 ,  C21D8/02 ,  C21D1/02 ,  C21D8/10 ,  C22C38/38 ,  C22C38/00 ,  C22C38/04 ,  C22C38/18 ,  C22C38/12 ,  C22C38/14 ,  C21D1/20 ,  C22C38/02 ,  C22C38/06 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/42 ,  C22C38/50 ,  C22C38/54 ,  C22C38/58

Abstract: Provided are a high-strength hot-rolled steel sheet and a method for manufacturing the steel sheet. The steel sheet includes C: 0.060% or more and 0.140% or less, Si: 1.00% or less, Mn: 1.30% or more and 2.50% or less, P: 0.030% or less, S: 0.0050% or less, Al: 0.070% or less, N: 0.010% or less, Ti: 0.060% or more and 0.140% or less, Cr: 0.10% or more and 0.50% or less, B: 0.0002% or more and 0.0020% or less, and the balance being Fe and inevitable impurities, in which the relationship 5.0≤18C+Mn+1.3Cr+1500B≤6.0 is obtained. The microstructure includes a bainite phase in an amount of more than 90% one, two, or all of a ferrite phase, a martensite phase, and a retained austenite phase in an amount of less than 10%.

公开(公告)号：US20210140007A1

公开(公告)日：2021-05-13

申请号：US17262884

申请日：2019-06-10

Applicant: JFE Steel Corporation

Inventor： Kazuhiko Yamazaki ,  Takeshi Yokota ,  Sumio Kaiho ,  Noriaki Moriyasu

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

Abstract: Provided is a high-strength hot rolled steel sheet that has excellent stretch flange formability, bendability, and low-temperature toughness while maintaining high strength of a tensile strength TS of 1180 MPa or more, and a method for manufacturing the high-strength hot rolled steel sheet.
The high-strength hot rolled steel sheet includes a specific chemical composition, and a steel structure in which a lower bainite phase and/or a tempered martensite phase at 90% or more in terms of a total area fraction is contained as a dominant phase, an average grain size of the dominant phase is 10.0 μm or less, and an amount of Fe in Fe-based precipitates is 0.70% or less in mass %, in which an arithmetic average roughness (Ra) of a surface is 2.50 μm or less, and a tensile strength TS is 1180 MPa or more.

公开(公告)号：US20210129491A1

公开(公告)日：2021-05-06

申请号：US16491717

申请日：2018-02-26

Applicant: JFE Steel Corporation

Inventor： Sota Goto ,  Kazuhiko Yamazaki ,  Taro Kizu ,  Shunsuke Toyoda

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

Abstract: Provided is a high-strength hot-rolled coated steel sheet with excellent formability,
A high-strength hot-rolled coated steel sheet has a constituent composition containing, in a mass percent, C: 0.03% to 0.15%, Si: 0.4% or less, Mn: 1.2% to 1.9%, Ti: 0.05% to 0.25%, B: 0.0005% to 0.0050%, P: 0.03% or less, S: 0.005% or less, Al: 0.005% to 0.4%, and N: 0.01% or less, the balance being Fe and incidental impurities. The total area fraction of one or more of ferrite and tempered bainite is 90% or more. The steel sheet has a structure in which the volume fraction of Ti carbides having particle sizes of 20 nm or less is 0.05 vol % or more.

公开(公告)号：US20150368741A1

公开(公告)日：2015-12-24

申请号：US14764818

申请日：2014-01-23

Applicant: JFE STEEL CORPORATION

Inventor： Katsumi Nakajima ,  Kazuhiko Yamazaki ,  Chikara Kami

IPC: C21D9/46 ,  C22C38/28 ,  C22C38/24 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C21D8/02

CPC classification number: C21D9/46 ,  C21D8/0226 ,  C21D2211/004 ,  C21D2211/005 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/24 ,  C22C38/28 ,  C22C38/54 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  Y02P10/212

Abstract: There are provided a high-strength hot-rolled steel sheet having high burring formability and a method for manufacturing the high-strength hot-rolled steel sheet. A high-strength hot-rolled steel sheet having high burring formability contains, on a mass percent basis, C: 0.06% or more and 0.13% or less, Si: less than 0.5%, Mn: more than 0.5% and 1.4% or less, P: 0.05% or less, S: 0.005% or less, N: 0.01% or less, Al: 0.1% or less, Ti: 0.05% or more and 0.25% or less, and V: more than 0.15% and 0.4% or less such that S, N, Ti, and V satisfy Ti.+V≧0.35 (wherein Ti.═Ti—N×(48/14)−S×(48/32), and S, N, Ti, and V denote the amounts (% by mass) of the corresponding elements), the remainder being Fe and incidental impurities, wherein the high-strength hot-rolled steel sheet has a microstructure in which a ferrite phase fraction is more than 90%, a carbide containing Ti is precipitated, and 70% or more of the carbide has a grain size of less than 9 nm.

Abstract translation: 提供了一种具有高切削成形性的高强度热轧钢板和一种制造该高强度热轧钢板的方法。 具有高成型性的高强度热轧钢板以质量％计含有C：0.06％以上且0.13％以下，Si：小于0.5％，Mn：大于0.5％和1.4％，或 较小，P：0.05％以下，S：0.005％以下，N：0.01％以下，Al：0.1％以下，Ti：0.05％以上且0.25％以下，V：大于0.15％， 0.4％以下，使得S，N，Ti和V满足Ti +V≥0.35（其中Ti = Ti-N×（48/14）-S×（48/32），S，N，Ti ，V表示相应元素的量（质量％）），余量为Fe和附带杂质，其中高强度热轧钢板具有铁素体相分数大于90％的微观结构， 含有Ti的碳化物析出，70％以上的碳化物的晶粒尺寸小于9nm。

公开(公告)号：US20240376578A1

公开(公告)日：2024-11-14

申请号：US18691606

申请日：2022-09-09

Applicant: JFE Steel Corporation

Inventor： Kazuhiko Yamazaki ,  Masaki Tada

IPC: C22C38/04 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C23C2/06

Abstract: A steel sheet for hot pressing, a method for producing the steel sheet, a hot-pressed member, and a method for producing the hot-pressed member are disclosed. The steel sheet for hot pressing contains specific components, wherein ferrite constitutes 30% or more and 90% or less by area, pearlite constitutes 10% or more and 70% or less by area, and a remaining microstructure constitutes 5% or less by area, the ferrite has an average aspect ratio in the range of 2.0 or more and 12.0 or less, and the ferrite has an average minor axis length of 5.0 μm or less, the steel sheet contains 500/μm3 or more and 6000/μm3 or less of Ti—Nb complex precipitates with a grain size of 3 nm or more and 50 nm or less, and the steel sheet has a dislocation density of 1.0×1015/m2 or more.

公开(公告)号：US11603571B2

公开(公告)日：2023-03-14

申请号：US16485978

申请日：2018-02-06

Applicant: JFE Steel Corporation

Inventor： Kazuhiko Yamazaki ,  Shunsuke Toyoda ,  Noriaki Moriyasu ,  Sumio Kaiho

IPC: C22C38/02 ,  C21D8/02 ,  C22C38/04 ,  C22C38/06

Abstract: There are provided a high-strength hot-rolled steel sheet having a tensile strength of 980 MPa or more and a production method therefor. The high-strength hot-rolled steel sheet has a predetermined component composition and a microstructure containing 75.0% or more by area and less than 97.0% by area of a primary phase composed of an upper bainite phase, the primary phase having an average grain size of 12.0 μm or less, and more than 3.0% by area and 25.0% or less by area of a secondary phase that is a structure composed of one or two of a lower bainite phase and/or a tempered martensite phase, and a martensite phase, in which the number density of grains of the secondary phase having an equivalent circular diameter of 0.5 μm or more is 150,000 grains/mm2 or less, and the steel sheet has an arithmetic mean surface roughness of 2.00 μm or less.