公开(公告)号：US20200347473A1

公开(公告)日：2020-11-05

申请号：US16320328

申请日：2017-08-10

Applicant: JFE Steel Corporation

Inventor： Noriaki Kohsaka ,  Michitaka Sakurai ,  Yoshikazu Suzuki ,  Yoshimasa Himei

IPC: C21D9/46 ,  B32B15/01 ,  C23C2/06 ,  C23C2/40 ,  C22C38/58 ,  C22C38/54 ,  C22C38/50 ,  C22C38/44 ,  C22C38/42 ,  C22C38/24 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  C21D1/26

Abstract: A high-strength steel sheet contains, in mass %, C: 0.07 to 0.14%, Si: 0.65 to 1.65%, Mn: 1.8 to 2.6%, P: 0.05% or less, S: 0.005% or less, Al: 0.08% or less, N: 0.0060% or less, Ti: 0.005 to 0.030%, B: 0.0002 to 0.0030%, and either or both of Cr: 0.01 to 0.40% and Mo: 0.01 to 0.50% and satisfies the expression (1); where: an average grain size of a ferrite phase is 1.5 μm or less; an area ratio of the ferrite phase is 2% or more and 15% or less; an area ratio of a tempered martensite phase is 75% or more and 96% or less; and a total length per unit area of an interface between an untempered martensite phase and the ferrite phase and an interface between the untempered martensite phase and the tempered martensite phase is 6.3×108 μm/m2 to 5.0×1011 μm/m2.

公开(公告)号：US10590505B2

公开(公告)日：2020-03-17

申请号：US15554591

申请日：2016-01-14

Applicant: JFE STEEL CORPORATION

Inventor： Noriaki Kohsaka ,  Yoshimasa Funakawa ,  Michitaka Sakurai ,  Yoshikazu Suzuki

IPC: C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C22C38/60 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C22C38/00 ,  C22C18/04 ,  C22C18/00

Abstract: A high-strength steel sheet having a composition containing C: 0.09% to 0.17%, Si: 0.6% to 1.7%, Mn: 3.5% or less, P: 0.03% or less, S: 0.005% or less, Al: 0.08% or less, N: 0.006% or less, Ti: 0.05% or less, and B: 0.0002% to 0.0030% on a mass basis, the remainder being Fe and inevitable impurities. The steel sheet also has a microstructure containing less than 20% (including 0%) of a ferrite phase, 75% or more (including 100%) of a tempered martensite phase, 10% or less (including 0%) of an untempered martensite phase, and less than 5% (including 0%) of a retained austenite phase in terms of area fraction. The tempered martensite phase has a Vickers hardness of 280 to 340 and a tensile strength of 950 MPa to 1,120 MPa.

公开(公告)号：US12215405B2

公开(公告)日：2025-02-04

申请号：US17432218

申请日：2020-01-17

Applicant: JFE STEEL CORPORATION

Inventor： Katsutoshi Takashima ,  Minoru Tanaka ,  Yoshie Obata ,  Michitaka Sakurai

IPC: C21D9/48 ,  B32B15/01 ,  C21D6/00 ,  C21D8/04 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/42 ,  C22C38/44 ,  C22C38/46 ,  C22C38/48 ,  C22C38/50 ,  C22C38/54 ,  C22C38/58 ,  C22C38/60 ,  C21D9/00 ,  C23C2/06 ,  C23C2/40

Abstract: Provided is a hot-pressed member that combines both high strength of 1850 MPa or more in TS and excellent delayed fracture resistance. A hot-pressed member comprises: a predetermined chemical composition; a microstructure in which a prior austenite average grain size is 8 μm or less, a volume fraction of martensite is 95% or more, and a volume fraction of granular carbide of 0.1 μm or more in grain size is 0.10% to 4.0%; a Ni diffusion region of 2.0 μm or more in a depth direction in a surface layer; and a tensile strength of 1850 MPa or more.

公开(公告)号：US11186889B2

公开(公告)日：2021-11-30

申请号：US16320328

申请日：2017-08-10

Applicant: JFE Steel Corporation

Inventor： Noriaki Kohsaka ,  Michitaka Sakurai ,  Yoshikazu Suzuki ,  Yoshimasa Himei

IPC: C21D9/46 ,  B32B15/01 ,  C21D1/26 ,  C21D6/00 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/24 ,  C22C38/42 ,  C22C38/44 ,  C22C38/50 ,  C22C38/54 ,  C22C38/58 ,  C23C2/06 ,  C23C2/40

Abstract: A high-strength steel sheet contains, in mass %, C: 0.07 to 0.14%, Si: 0.65 to 1.65%, Mn: 1.8 to 2.6%, P: 0.05% or less, S: 0.005% or less, Al: 0.08% or less, N: 0.0060% or less, Ti: 0.005 to 0.030%, B: 0.0002 to 0.0030%, and either or both of Cr: 0.01 to 0.40% and Mo: 0.01 to 0.50% and satisfies the expression (1); where: an average grain size of a ferrite phase is 1.5 μm or less; an area ratio of the ferrite phase is 2% or more and 15% or less; an area ratio of a tempered martensite phase is 75% or more and 96% or less; and a total length per unit area of an interface between an untempered martensite phase and the ferrite phase and an interface between the untempered martensite phase and the tempered martensite phase is 6.3×108 μm/m2 to 5.0×1011 μm/m2.

公开(公告)号：US11850821B2

公开(公告)日：2023-12-26

申请号：US17425847

申请日：2019-12-26

Applicant: JFE Steel Corporation

Inventor： Katsutoshi Takashima ,  Minoru Tanaka ,  Kenji Tsuzumi ,  Shingo Arakawa ,  Michitaka Sakurai

IPC: C21D6/00 ,  B32B15/01 ,  B21B3/02 ,  C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/16 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C23C2/02 ,  C23C2/26 ,  C23C2/28 ,  C25D3/22

CPC classification number: B32B15/015 ,  B21B3/02 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/16 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C23C2/02 ,  C23C2/024 ,  C23C2/0224 ,  C23C2/26 ,  C23C2/28 ,  C21D2211/008 ,  C25D3/22

Abstract: A hot-pressed member has a predetermined chemical composition. In the hot-pressed member, a steel sheet has a microstructure in which a prior austenite average grain diameter is 8 μm or less, and martensite is present in a volume fraction of 95% or greater in a region within 30 μm of a surface; a Ni diffusion region having a thickness of 0.5 μm or greater exists in a surface layer; a standard deviation of Vickers hardness values is 35 or less; Mndif (mass %) in a sheet thickness direction ≤0.20, where Mndif (mass %) is a degree of Mn segregation; and a tensile strength is 1780 MPa or greater.

公开(公告)号：US20140102596A1

公开(公告)日：2014-04-17

申请号：US14058580

申请日：2013-10-21

Applicant: JFE Steel Corporation

Inventor： Yoshihiko Ono ,  Kenji Takahashi ,  Kaneharu Okuda ,  Shoichiro Taira ,  Michitaka Sakurai ,  Yusuke Fushiwaki

IPC: C21D8/02

CPC classification number: C21D8/0236 ,  C21D8/02 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/04 ,  C22C38/06 ,  C22C38/58

Abstract: A method of manufacturing a high strength cold rolled steel sheet includes hot-rolling and cold-rolling a steel slab annealing the steel sheet at an annealing temperature of 750° C. to 830° C.; subjecting the steel sheet to first cooling at an average cooling rate of 3° C./sec to 40° C./sec in a temperature range from the annealing temperature to 480° C.; subjecting the steel sheet to second cooling at an average cooling rate of 8° C./sec to 80° C./sec in a temperature range from 480° C. to Tc (° C.) given by formula (6): Tc=435−40×[% Mn]−30×[% Cr]−30×[% V](6) wherein [% A] is the content (% by mass) of alloying element A; and subjecting the steel sheet to third cooling at an average cooling rate of 0.3° C./sec to 30° C./sec in a temperature range from Tc (° C.) to 200° C.

Abstract translation: 制造高强度冷轧钢板的方法包括在退火温度为750℃至830℃的条件下对钢板进行热轧和冷轧。 在退火温度至480℃的温度范围内以3℃/秒至40℃/秒的平均冷却速度对钢板进行第一次冷却; 在由式（6）给出的480℃至Tc（℃）的温度范围内以8℃/秒至80℃/秒的平均冷却速率对钢板进行第二次冷却：Tc = 435-40×[％Mn] -30×[％Cr] -30×[％V]（6）其中[％A]为合金元素A的含量（质量％）; 在Tc（℃）〜200℃的温度范围内以0.3℃/秒〜30℃/秒的平均冷却速度对钢板进行第3次冷却。

公开(公告)号：US12276006B2

公开(公告)日：2025-04-15

申请号：US17760362

申请日：2020-11-19

Applicant: JFE STEEL CORPORATION

Inventor： Shunsuke Yamamoto ,  Shotaro Terashima ,  Yuki Takeda ,  Michitaka Sakurai ,  Katsuya Hoshino ,  Yoshiyasu Kawasaki

IPC: C21D9/46 ,  C21D1/26 ,  C21D6/00 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/16 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C23C2/02 ,  C23C2/28 ,  C23C2/40

Abstract: To obtain a high-strength hot-dip galvanized steel sheet having excellent surface appearance even in the case where a steel strip containing Mn at a predetermined ratio or more to Si is subjected to hot-dip galvanizing treatment, a method of producing a hot-dip galvanized steel sheet using a continuous hot-dip galvanizing apparatus comprises: subjecting a steel strip to annealing, by conveying it in an annealing furnace; and subjecting the steel strip discharged from a cooling zone to hot-dip galvanizing using a hot-dip galvanizing line, to obtain a hot-dip galvanized steel sheet. The steel strip has a chemical composition containing, in mass %, Mn: 1.7% or more and 3.5% or less and Si: 0.2% or more and 1.05% or less and satisfying [Si]/[Mn]≤0.30. The chemical composition, a dew point of an atmosphere in the soaking zone, and a delivery temperature of the heating zone satisfy Formula (1).

公开(公告)号：US20220118741A1

公开(公告)日：2022-04-21

申请号：US17425847

申请日：2019-12-26

Applicant: JFE Steel Corporation

Inventor： Katsutoshi Takashima ,  Minoru Tanaka ,  Kenji Tsuzumi ,  Shingo Arakawa ,  Michitaka Sakurai

IPC: B32B15/01 ,  B21B3/02 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/16 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00

Abstract: A hot-pressed member has a predetermined chemical composition. In the hot-pressed member, a steel sheet has a microstructure in which a prior austenite average grain diameter is 8 μm or less, and martensite is present in a volume fraction of 95% or greater in a region within 30 μm of a surface; a Ni diffusion region having a thickness of 0.5 μm or greater exists in a surface layer; a standard deviation of Vickers hardness values is 35 or less; Mndif (mass %) in a sheet thickness direction ≤0.20, where Mndif (mass %) is a degree of Mn segregation; and a tensile strength is 1780 MPa or greater.

公开(公告)号：US09534269B2

公开(公告)日：2017-01-03

申请号：US14058580

申请日：2013-10-21

Applicant: JFE Steel Corporation

Inventor： Yoshihiko Ono ,  Kenji Takahashi ,  Kaneharu Okuda ,  Shoichiro Taira ,  Michitaka Sakurai ,  Yusuke Fushiwaki

IPC: C21D8/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/58

CPC classification number: C21D8/0236 ,  C21D8/02 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/04 ,  C22C38/06 ,  C22C38/58

Abstract: A method of manufacturing a high strength cold rolled steel sheet includes hot-rolling and cold-rolling a steel slab annealing the steel sheet at an annealing temperature of 750° C. to 830° C.; subjecting the steel sheet to first cooling at an average cooling rate of 3° C./sec to 40° C./sec in a temperature range from the annealing temperature to 480° C.; subjecting the steel sheet to second cooling at an average cooling rate of 8° C./sec to 80° C./sec in a temperature range from 480° C. to Tc (° C.) given by formula (6): Tc=435−40×[% Mn]−30×[% Cr]−30×[% V]  (6) wherein [% A] is the content (% by mass) of alloying element A; and subjecting the steel sheet to third cooling at an average cooling rate of 0.3° C./sec to 30° C./sec in a temperature range from Tc (° C.) to 200° C.

Abstract translation: 提供一种用于例如通过压制成型工艺的汽车的压制成形用高强度冷轧钢板和这种钢板的制造方法。 多相钢板具有以质量％计含有0.015％以上且小于0.100％的碳，小于0.40％的硅，1.0〜1.9％的锰，超过0.015％〜0.05％的钢， 磷，0.03％以下的硫，0.01〜0.3％的可溶性铝，0.005％以下的氮，少于0.30％的铬，0.0050％以下的硼，小于0.15％的钼，0.4％以下 的钒，0.02％以下的钛，以及任选的铌，钨，锆，铜，镍，锡，锑，钙，铈，镧和镁中的至少一种，其中[Mneq]为2.0〜2.8， 是铁和杂质。 钢组成满足特定要素的多个参数公式。 钢板具有包含铁素体的微结构，并且含有马氏体的第二相的特定体积分数保留为3。