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公开(公告)号：US20170152580A1
公开(公告)日：2017-06-01
申请号：US15327489
申请日：2015-06-09
发明人： Hideyuki Kimura , Koichiro Fujita , Hiroshi Hasegawa , Mai Aoyama
IPC分类号： C21D9/46 , B21B3/00 , C23C2/06 , C23C2/40 , C23G1/08 , C21D8/02 , C22C38/38 , C22C38/28 , C22C38/26 , C22C38/24 , C22C38/14 , C22C38/12 , C22C38/06 , C22C38/04 , C22C38/02 , C22C38/00 , B21B1/26
CPC分类号： C21D9/46 , B21B1/26 , B21B1/28 , B21B3/00 , C21D8/0226 , C21D8/0236 , C21D8/0263 , C21D8/0278 , C21D2211/001 , C21D2211/002 , C21D2211/005 , C21D2211/008 , C22C18/00 , C22C38/00 , C22C38/001 , C22C38/002 , C22C38/02 , C22C38/04 , C22C38/06 , C22C38/12 , C22C38/14 , C22C38/24 , C22C38/26 , C22C38/28 , C22C38/38 , C22C38/58 , C23C2/02 , C23C2/06 , C23C2/28 , C23C2/40 , C23G1/081 , C23G1/085
摘要： A method for manufacturing a high-strength galvanized steel sheet includes performing hot rolling, cold rolling, first annealing, pickling, and second annealing. The first annealing is performed to obtain a steel sheet having a steel microstructure including ferrite in an amount of 10% or more and 60% or less in terms of area ratio, and martensite, bainite, and retained austenite in a total amount of 40% or more and 90% or less in terms of area ratio. The second annealing includes heating to an annealing temperature of 750° C. or higher and 850° C. or lower, holding at the annealing temperature for 10 seconds or more and 500 seconds or less, cooling at an average cooling rate of 1° C./s or more and 15° C./s or less, performing a galvanizing treatment, and cooling to a temperature of 150° C. or lower at an average cooling rate of 5° C./s or more and 100° C./s or less.
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公开(公告)号：US11788163B2
公开(公告)日：2023-10-17
申请号：US17042291
申请日：2019-03-20
发明人： Kazuki Endo , Yoshiyasu Kawasaki , Yuki Toji , Yoshimasa Funakawa , Mai Aoyama
IPC分类号： C21D9/46 , C22C38/38 , C22C38/28 , C22C38/16 , C22C38/12 , C22C38/08 , C22C38/06 , C22C38/02 , C21D8/02 , C21D6/00 , C22C38/00 , C23C2/02 , C23C2/06 , C23C2/28 , C23C2/40
CPC分类号： C21D9/46 , C21D6/001 , C21D6/002 , C21D6/005 , C21D6/008 , C21D8/0205 , C21D8/0226 , C21D8/0236 , C21D8/0263 , C22C38/001 , C22C38/002 , C22C38/005 , C22C38/008 , C22C38/02 , C22C38/06 , C22C38/08 , C22C38/12 , C22C38/16 , C22C38/28 , C22C38/38 , C23C2/02 , C23C2/06 , C23C2/28 , C23C2/40 , C21D2211/001 , C21D2211/005 , C21D2211/008
摘要： A high-strength steel sheet includes a steel structure with: ferrite being 35% to 80% and tempered martensite being greater than 5% and 20% or less in terms of area fraction; retained austenite being 8% or more in terms of volume fraction; an average grain size of: the ferrite being 6 μm or less; and the retained austenite being 3 μm or less; a value obtained by dividing an area fraction of blocky austenite by a sum of area fractions of lath-like austenite and the blocky austenite being 0.6 or more; a value obtained by dividing, by mass %, an average Mn content in the retained austenite by an average Mn content in the ferrite being 1.5 or more; and a value obtained by dividing, by mass %, an average C content in the retained austenite by an average C content in the ferrite being 3.0 or more.
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公开(公告)号：US20210010100A1
公开(公告)日：2021-01-14
申请号：US17041567
申请日：2019-03-26
IPC分类号： C21D9/46 , C23C2/06 , C23C2/28 , C23C2/40 , C22C38/02 , C22C38/04 , C22C38/06 , C22C38/00 , C22C38/08 , C22C38/12 , C22C38/14 , C22C38/16 , C22C38/32 , C22C38/60 , C21D8/02
摘要： A method for producing a high-strength hot-dip galvannealed steel sheet, in which a high-strength steel sheet is used as a base material, includes a rolling step (x) of rolling a hot-dip galvannealed steel sheet with a coating layer having an Fe concentration of 8% to 17% by mass, and a heat treatment step (y) of heating the coated steel sheet which has been subjected to the rolling step (x) under the conditions satisfying the following formulae (1) and (2): (273+T)×(20+2×log10(t))≥8000 (1) 40≤T≤160 (2) where T: heating temperature (° C.) of the coated steel sheet, and t: holding time (hr) at the heating temperature T.
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公开(公告)号：US11661642B2
公开(公告)日：2023-05-30
申请号：US17042250
申请日：2019-03-20
发明人： Kazuki Endo , Yoshiyasu Kawasaki , Yuki Toji , Yoshimasa Funakawa , Mai Aoyama
CPC分类号： C22C38/04 , B21B27/106 , C21D6/005 , C21D8/0226 , C22C33/0264
摘要： A high-strength steel sheet includes a steel structure with: ferrite being 35% to 80%, martensite being 5% to 35%, and tempered martensite being 0% to 5% in terms of area fraction; retained austenite being 8% or more in terms of volume fraction; an average grain size of: the ferrite being 6 μm or less; and the retained austenite being 3 μm or less; a value obtained by dividing an area fraction of blocky austenite by a sum of area fractions of lath-like austenite and the blocky austenite being 0.6 or more; a value obtained by dividing, by mass %, an average Mn content in the retained austenite by an average Mn content in the ferrite being 1.5 or more; and a value obtained by dividing, by mass %, an average C content in the retained austenite by an average C content in the ferrite being 3.0 or more.
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公开(公告)号：US10570474B2
公开(公告)日：2020-02-25
申请号：US15323163
申请日：2015-06-15
发明人： Mai Aoyama , Yoshitsugu Suzuki , Hideyuki Kimura
IPC分类号： C21D9/46 , B21B3/00 , C23C2/02 , C23C2/06 , C22C38/06 , C22C38/60 , B21B1/26 , C22C38/00 , B21B1/28 , C23C2/28 , B21B1/22 , C21D8/02 , C22C38/02 , C22C38/04 , C22C38/08 , C22C38/12 , C22C38/14 , C22C38/16 , C22C38/22 , C22C38/26 , C22C38/28 , C22C38/38 , C23C2/40 , C23G1/00
摘要： A method for manufacturing a high-strength galvanized steel sheet. The method includes a first heating step of holding the steel sheet in a temperature range of 750° C. to 880° C. for 20 s to 600 s in an atmosphere having an H2 concentration of 0.05% to 25.0% by volume and a dew point of −45° C. to −10° C., a cooling step, a rolling step of rolling the steel sheet with a rolling reduction of 0.3% to 2.0%, a pickling step of pickling the steel sheet with a pickling weight loss of 0.02 gram/m2 to 5 gram/m2 in terms of Fe, a second heating step of holding the steel sheet in a temperature range of 720° C. to 860° C. for 20 sec. to 300 sec. in an atmosphere having an H2 concentration of 0.05% to 25.0% by volume and a dew point of −10° C. or lower, and a galvanizing step.
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公开(公告)号：US10329638B2
公开(公告)日：2019-06-25
申请号：US15329117
申请日：2015-06-10
发明人： Hideyuki Kimura , Hiroshi Hasegawa , Noriaki Kohsaka , Mai Aoyama
IPC分类号： C21D9/46 , C23C2/02 , C23C2/06 , C23C2/26 , C23C2/28 , C22C38/00 , C22C38/14 , C22C38/58 , B21B1/22 , B32B15/01 , C21D8/02 , C22C38/02 , C22C38/04 , C22C38/06 , C22C38/12 , C22C38/24 , C22C38/26 , C22C38/28 , C22C38/32 , C22C38/38 , C22C18/00
摘要： A high strength galvanized steel sheet that has a tensile strength (TS) of 780 MPa or higher and excellent bendability, fatigue resistance, and surface appearance quality and a method for producing the high strength galvanized steel sheet. The steel sheet includes, at a position ½ of a thickness of the steel sheet, 5% or more and 80% or less of a ferrite phase in terms of area fraction, 20% or more and 70% or less of a martensite phase in terms of area fraction, and 0% or more and 25% or less of a bainite phase in terms of area fraction.
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公开(公告)号：US20240318290A1
公开(公告)日：2024-09-26
申请号：US18577328
申请日：2022-06-09
CPC分类号： C23C2/0224 , C22C38/002 , C22C38/02 , C22C38/04 , C23C2/004 , C23C2/285 , C23C2/40
摘要： When a hot-dip galvanizing treatment is performed on a steel sheet containing Si in an amount of 0.2 mass % or more by using a continuous hot-dip galvanizing apparatus including an annealing furnace in which a heating zone, a soaking zone, and a cooling zone are arranged in this order, a snout adjacent to the cooling zone, and hot-dip galvanizing equipment, a humidified nitrogen-hydrogen gas mixture containing moisture in such a manner that a certain expression is satisfied is supplied into a region on the downstream side of the soaking zone, gas nozzles are arranged over the entire perimeter of an inner wall of the snout, nitrogen gas or a nitrogen-hydrogen gas mixture is supplied through the gas nozzles downward along the inner wall, and the dew point in the snout is controlled to be −50° C. to −35° C.
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公开(公告)号：US11643700B2
公开(公告)日：2023-05-09
申请号：US17043514
申请日：2019-03-20
发明人： Yoshiyasu Kawasaki , Kazuki Endo , Yuki Toji , Yoshimasa Funakawa , Satoshi Maeda , Mai Aoyama
IPC分类号： C21D9/46 , B32B15/00 , C21D6/00 , C21D8/00 , C22C38/00 , B32B15/01 , C21D8/02 , C22C38/02 , C22C38/04 , C22C38/06 , C22C38/42 , C22C38/44 , C22C38/46 , C22C38/48 , C22C38/50 , C22C38/54 , C23C2/02 , C23C2/06 , C23C2/28 , C23C2/40
CPC分类号： C21D9/46 , B32B15/013 , C21D6/004 , C21D6/005 , C21D6/008 , C21D8/0205 , C21D8/0226 , C21D8/0236 , C21D8/0263 , C22C38/001 , C22C38/002 , C22C38/005 , C22C38/008 , C22C38/02 , C22C38/04 , C22C38/06 , C22C38/42 , C22C38/44 , C22C38/46 , C22C38/48 , C22C38/50 , C22C38/54 , C23C2/02 , C23C2/06 , C23C2/28 , C23C2/40 , C21D2211/001 , C21D2211/003 , C21D2211/005 , C21D2211/008
摘要： A high-strength steel includes a steel structure with: in area fraction, 60.0% to less than 90.0% of ferrite, 0% to less than 5.0% of unrecrystallized ferrite, 2.0% to 25.0% of martensite, 0% to 5.0% of carbide, and 0% to 3.0% of bainite; in volume fraction, more than 7.0% of retained austenite; in a cross-sectional view of 100 μm×100 μm, a value obtained by dividing number of retained austenite that are not adjacent to retained austenite whose crystal orientations are different by a total number of retained austenite being less than 0.80, an average crystal grain size of the ferrite being 6.0 μm or less, an average crystal grain size of the retained austenite being 3.0 μm or less, and a value obtained by dividing, by mass %, an average content of Mn in the retained austenite by an average content of Mn in steel being 1.50 or more.
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公开(公告)号：US20200347479A1
公开(公告)日：2020-11-05
申请号：US16960733
申请日：2018-12-13
发明人： Mai Aoyama , Kazuaki Tsuchimoto , Yusuke Fushiwaki
IPC分类号： C21D9/46 , B32B15/01 , C22C38/38 , C22C38/28 , C22C38/12 , C22C38/08 , C22C38/06 , C22C38/02 , C22C38/00 , C21D6/00 , C25D5/36 , C25D5/50
摘要： Provided are a high-strength electrogalvannealed steel sheet that has a TS of 780 MPa or higher and a method for manufacturing the high-strength electrogalvannealed steel sheet. The high-strength electrogalvannealed steel sheet has a composition including, in terms of % by mass, C: 0.030% or more and 0.250% or less, Si: 0.01% or more and 3.00% or less, Mn: 1.00% or more and 10.00% or less, P: 0.001% or more and 0.100% or less, and S: 0.0001% or more and 0.0200% or less, with the balance being Fe and unavoidable impurities. The steel sheet has an electrogalvannealed coating layer on a surface thereof. The electrogalvannealed coating layer has an Fe content of 8.0% to 15.0%. The steel sheet has a tensile strength of 780 MPa or higher. The steel sheet has a diffusible hydrogen content of 0.2 wt. ppm or less.
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公开(公告)号：US10704117B2
公开(公告)日：2020-07-07
申请号：US15746203
申请日：2016-07-28
IPC分类号： C21D9/46 , C22C38/06 , C22C38/60 , C21D8/02 , C23C2/06 , C22C38/00 , C22C38/02 , C22C38/04 , C22C38/08 , C22C38/12 , C22C38/14 , C22C38/16 , C22C38/28 , C22C38/32 , C21D6/00 , C23C2/02 , C22C38/38 , C23C8/14 , C23C2/28 , C23C2/40 , C23F17/00
摘要： Provided are a cold-rolled steel sheet which can preferably be used for manufacturing a high-strength galvanized steel sheet and methods for manufacturing the steel sheets. The cold-rolled steel sheet has a specified chemical composition, in which the Mn concentration in a surface layer of the steel sheet satisfies relational expression (1) and relational expression (2) below. 8≤(Cp/Cc)×Mn . . . (1) (Cmin/Cc)×Mn≤2.5 . . . (2) where Cp: maximum Mn concentration in a region within 0.5 μm of the surface of a steel sheet in the thickness direction; Cc: average Mn concentration in a region from a position located 5 μm from a surface of a steel sheet in the thickness direction to a position located 5 μm from an opposite surface in the thickness direction; Cmin: minimum Mn concentration in a region from 0.5 μm to 5 μm from the surface of a steel sheet in the thickness direction; and Mn: Mn content (mass %).
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