公开(公告)号：US20220090224A1

公开(公告)日：2022-03-24

申请号：US17420024

申请日：2019-12-24

申请人： NIPPON STEEL CORPORATION

发明人： Takeshi TOYODA ,  Hitoshi NIKAIDO ,  Kohei NAKADA ,  Yui YAMASHITA ,  Kazuki MATSUDA

IPC分类号： C21D9/46 ,  C21D9/50 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/50 ,  B23K9/16 ,  C22C38/58 ,  C22C38/54 ,  C22C38/46 ,  C22C38/44 ,  C22C38/42

摘要： Hot-rolled steel sheet having a chemical composition including, in mass %, C: 0.02 to 0.20%, Si: 0.01 to 1.50%, Mn: 0.10 to 3.00%, P: 0.10% or less, S: 0.010% or less, Al: 0.005 to 0.100%, Ti: 0.02 to 0.20%, N: 0.001 to 0.010%, Cu: 0 to 0.50%, Ni: 0 to 0.50%, Cr: 0 to 1.00%, Mo: 0 to 0.40%, Nb: 0 to 0.060%, V: 0 to 1.00%, B: 0 to 0.0100%, Ca: 0 to 0.0050%, O: 0.0100% or less, and the balance: Fe and impurities; in which: a steel micro-structure includes, in area %, ferrite: 60 to 80%, and a total of ferrite and bainite: 90% or more; an average of the crystal grain size of ferrite and bainite is 7.0 μm or less, a standard deviation of the crystal grain size is 2.0 or less; and a standard deviation of a diameter of Ti carbo-nitrides is 10 nm or less.

公开(公告)号：US20220145417A1

公开(公告)日：2022-05-12

申请号：US17434981

申请日：2020-03-12

申请人： NIPPON STEEL CORPORATION

发明人： Kengo TAKEDA ,  Hitoshi NIKAIDO ,  Hiroyuki KAWATA ,  Takafumi YOKOYAMA

IPC分类号： C21D9/46 ,  C22C38/58 ,  C22C38/54 ,  C22C38/52 ,  C22C38/50 ,  C22C38/48 ,  C22C38/44 ,  C22C38/10 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00

摘要： Provided are: a steel sheet having a high strength and excellent stretch formability; and a method of producing the same. The steel sheet has prescribed chemical composition and structure, in which the integration degree of the (111) orientation of ferrite is 3.0 or higher, and the integration degree of the (252) orientation of martensite and tempered martensite is 5.0 or lower. The method of producing the steel sheet includes: the step of continuously casting a molten steel having the prescribed chemical composition, and performing 5 to 40% rolling reduction at a temperature of 800° C. to lower than 1,200° C. in a period after the continuous casting until cooling to room temperature; the hot rolling step of performing hot rolling with a finishing temperature of 650 to 950° C.; the step of coiling the resulting hot-rolled steel sheet at a coiling temperature of 400 to 700° C.; the step of retaining the hot-rolled steel sheet at (coiling start temperature+20° C. to 100° C.) for 5 to 300 minutes; the step of cold rolling the hot-rolled steel sheet at a rolling reduction ratio of 10.0 to 90.0%; and the step of annealing the resulting cold-rolled steel sheet at 700 to 900° C.

公开(公告)号：US20240167133A1

公开(公告)日：2024-05-23

申请号：US18285239

申请日：2021-06-22

申请人： NIPPON STEEL CORPORATION

发明人： Naoko KATOU ,  Eisaku SAKURADA ,  Hitoshi NIKAIDO

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

CPC分类号： C22C38/14 ,  C21D6/005 ,  C21D8/0226 ,  C21D8/0263 ,  C21D9/46 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C21D2211/009

摘要： This hot-rolled steel sheet has a predetermined chemical composition and has a metallographic structure containing ferrite with an area ratio of 53.0% or more and 76.0% or less, martensite with an area ratio of 3.0% or more and 10.0% or less, bainite with an area ratio of 14.0% or more and 39.0% or less, and pearlite with an area ratio of 2.6% or less, and with an average diameter of martensite of 0.26 μm or more and 0.70 μm or less, wherein, among all interfaces of the martensite, the total length of the interfaces between the martensite and the bainite is 75.0% or more with respect to the total length of all interfaces of the martensite.

公开(公告)号：US20230141963A1

公开(公告)日：2023-05-11

申请号：US17915354

申请日：2021-03-30

申请人： NIPPON STEEL CORPORATION

发明人： Yasuaki TANAKA ,  Hitoshi NIKAIDO ,  Hiroyuki KAWATA ,  Natsuko SUGIURA

IPC分类号： C22C38/58 ,  C22C38/50 ,  C22C38/48 ,  C22C38/42 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00

CPC分类号： C22C38/58 ,  C22C38/50 ,  C22C38/48 ,  C22C38/42 ,  C22C38/06 ,  C22C38/02 ,  C22C38/002

摘要： There is provided a steel sheet including a chemical composition consisting of, in mass %: C: 0.03 to 0.25%, Si: 0.1 to 2.0%, Mn: 1.0 to 3.0%, P: 0.200% or less, S: 0.0500% or less, Al: 0.01 to 1.00%, N: 0.0100% or less, and Ti: 0.01 to 0.25%, with the balance: Fe and impurities, and a steel micro-structure containing, in area %: ferrite: 50 to 85%, the balance being one or more kinds selected from martensite, bainite, and retained austenite, and an intensity of γ-fiber is more than 4.0 times in terms of random intensity ratio, and an average KAM value of grains having crystal orientations that form angles within 10° from γ-fiber is 1.30° or less.