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公开(公告)号：US20220010397A1
公开(公告)日：2022-01-13
申请号：US17285375
申请日：2019-10-16
IPC分类号： C21D9/46 , C21D8/02 , C21D1/22 , C21D6/00 , C22C38/58 , C22C38/54 , C22C38/50 , C22C38/42 , C22C38/44 , C22C38/14 , C22C38/12 , C22C38/04 , C22C38/02 , C22C38/06 , C22C38/00
摘要： A steel sheet having a specified chemical composition and a method for producing the steel sheet. The steel sheet has a microstructure comprising ferrite: 5% or less, and at least one of upper bainite, fresh martensite, tempered martensite, lower bainite, and retained γ: 95% to 100%, and retained γ: 5% to 20%. Retained γUB has a specified area percentage SγUB, retained γLB has a specified distribution number NγLB, and at least one of (i) fresh martensite has a specified equivalent circular grain diameter and aspect ratio and (ii) retained γ grains has a specified equivalent circular grain diameter and aspect ratio.
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公开(公告)号：US20220154301A1
公开(公告)日：2022-05-19
申请号：US17434255
申请日：2020-02-28
发明人： Yoichiro MATSUI , Yuka MIYAMOTO , Takeshi YOKOTA
IPC分类号： C21D9/46 , C22C38/54 , C22C38/28 , C22C38/26 , C22C38/24 , C22C38/22 , C22C38/06 , C22C38/04 , C22C38/02 , C22C38/00 , C21D8/02 , C21D6/00
摘要： A steel sheet and a member excellent in cold workability, hardenability, and post-quenching surface layer hardness, and methods for manufacturing the steel sheet and the member. The steel sheet has a specified chemical composition and a microstructure containing ferrite and carbides, a ratio of the volume of ferrite and carbides to the volume of the entire microstructure is 90% or more, a ratio of the volume of proeutectoid ferrite to the volume of the entire microstructure is 20% or more and 80% or less, a Mn concentration in the carbides is 0.10 mass % or more and 0.50 mass % or less, and a ratio of the number of carbides with particle diameters of 1 μm or more to the total number of carbides is 30% or more and 60% or less.
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公开(公告)号：US20210355559A1
公开(公告)日：2021-11-18
申请号：US17286148
申请日：2019-10-16
IPC分类号： C21D9/46 , C21D8/02 , C21D6/00 , C21D1/20 , C22C38/58 , C22C38/54 , C22C38/50 , C22C38/44 , C22C38/42 , C22C38/14 , C22C38/12 , C22C38/60 , C22C38/06 , C22C38/04 , C22C38/02 , C22C38/00
摘要： A steel sheet having a specified chemical composition and a method for producing the steel sheet. The steel sheet has a microstructure comprising ferrite: 5% or less, and at least one of upper bainite, fresh martensite, tempered martensite, lower bainite, and retained γ: 95% to 100% by area percentage, and retained γ: 4% to 15% by volume percentage. Retained γUB has a specified area percentage SγUB, retained γLB has a specified distribution number NγLB, and at least one of (i) fresh martensite has a specified equivalent circular grain diameter and aspect ratio and (ii) retained γ grains has a specified equivalent circular grain diameter and aspect ratio.
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公开(公告)号：US20210324492A1
公开(公告)日：2021-10-21
申请号：US17285304
申请日：2019-10-16
IPC分类号： C21D9/46 , C21D8/02 , C21D6/00 , C22C38/60 , C22C38/16 , C22C38/14 , C22C38/12 , C22C38/06 , C22C38/04 , C22C38/02 , C22C38/00 , C22C38/08 , B32B15/01
摘要： A steel sheet having a specified chemical composition and a method for producing the steel sheet. The steel sheet has a microstructure comprising ferrite: 6 to 90% in terms of an area fraction, and a constituent formed of at least one of upper bainite, fresh martensite, tempered martensite, lower bainite, and retained γ: 10 to 94% in terms of an area fraction, and retained γ: 3 to 15% in terms of a volume fraction. A total area fraction of SC-enriched is 0.1 to 5%, a total area fraction of SγBlock of at least one of (i) fresh martensite having a specified equivalent circular grain diameter and aspect ratio and (ii) retained γ grains having a specified equivalent circular grain diameter and aspect ratio is 5% or less, and prior γ in a surface layer has a grain diameter of 2 to 12 μm.
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