Patents by Inventor Ryoichi NISHIYAMA
Ryoichi NISHIYAMA has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
-
Patent number: 11649531Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 5 to 60%, and bainite: 40 to 95%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. A precipitate density of Ti(C,N) and Nb(C,N) each having a circle-equivalent diameter of 10 nm or less is 1010 precipitates/mm3 or more. A ratio (Hvs/Hvc) of a hardness at 20 ?m in depth from a surface (Hvs) to a hardness of the center of a sheet thickness (Hvc) is 0.85 or more.Type: GrantFiled: August 4, 2017Date of Patent: May 16, 2023Assignee: NIPPON STEEL CORPORATIONInventors: Kohichi Sano, Makoto Uno, Ryoichi Nishiyama, Yuji Yamaguchi, Natsuko Sugiura, Masahiro Nakata
-
Patent number: 11236412Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 30 to 95%, and bainite: 5 to 70%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. An average aspect ratio of ellipses equivalent to the crystal grains is 5 or less. An average distribution density of the total of Ti-based carbides and Nb-based carbides each having a grain size of 20 nm or more on ferrite grain boundaries is 10 carbides/?m or less.Type: GrantFiled: August 4, 2017Date of Patent: February 1, 2022Assignee: NIPPON STEEL CORPORATIONInventors: Kohichi Sano, Makoto Uno, Ryoichi Nishiyama, Yuji Yamaguchi, Natsuko Sugiura, Masahiro Nakata
-
Patent number: 11230755Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 0 to 30%, and bainite: 70 to 100%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. A grain boundary number density of solid-solution C or a grain boundary number density of the total of solid-solution C and solid-solution B is 1 piece/nm2 or more and 4.5 pieces/nm2 or less. An average grain size of cementite precipitated at grain boundaries is 2 ?m or less.Type: GrantFiled: August 4, 2017Date of Patent: January 25, 2022Assignee: NIPPON STEEL CORPORATIONInventors: Kohichi Sano, Makoto Uno, Ryoichi Nishiyama, Yuji Yamaguchi, Natsuko Sugiura, Masahiro Nakata
-
Patent number: 10889879Abstract: A steel sheet having a specific chemical composition and structure represented by, by area ratio, ferrite: 5 to 95%, and bainite: 5 to 95%. The proportion of crystal grains having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. Hard crystal grains A in which precipitates or clusters with a maximum diameter of 8 nm or less are dispersed in the crystal grains with a number density of 1×1016 to 1×1019 pieces/cm3. Soft crystal grains B in which precipitates or clusters with a maximum diameter of 8 nm or less are dispersed in the crystal grains with a number density of 1×1015 pieces/cm3 or less are contained. The volume % of the hard crystal grains A/(the volume % of the hard crystal grains A+the volume % of the soft crystal grains B) is 0.1 to 0.9.Type: GrantFiled: August 4, 2017Date of Patent: January 12, 2021Assignee: NIPPON STEEL CORPORATIONInventors: Kohichi Sano, Makoto Uno, Ryoichi Nishiyama, Yuji Yamaguchi, Natsuko Sugiura, Masahiro Nakata
-
Publication number: 20190309398Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 5 to 60%, and bainite: 40 to 95%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. A precipitate density of Ti(C,N) and Nb(C,N) each having a circle-equivalent diameter of 10 nm or less is 1010 precipitates/mm3 or more. A ratio (Hvs/Hvc) of a hardness at 20 ?m in depth from a surface (Hvs) to a hardness of the center of a sheet thickness (Hvc) is 0.85 or more.Type: ApplicationFiled: August 4, 2017Publication date: October 10, 2019Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kohichi SANO, Makoto UNO, Ryoichi NISHIYAMA, Yuji YAMAGUCHI, Natsuko SUGIURA, Masahiro NAKATA
-
Publication number: 20190241996Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 0 to 30%, and bainite: 70 to 100%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. A grain boundary number density of solid-solution C or a grain boundary number density of the total of solid-solution C and solid-solution B is 1 piece/nm2 or more and 4.5 pieces/nm2 or less. An average grain size of cementite precipitated at grain boundaries is 2 ?m or less.Type: ApplicationFiled: August 4, 2017Publication date: August 8, 2019Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kohichi SANO, Makoto UNO, Ryoichi NISHIYAMA, Yuji YAMAGUCHI, Natsuko SUGIURA, Masahiro NAKATA
-
Publication number: 20190233926Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 5 to 95%, and bainite: 5 to 95%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. Hard crystal grains A in which precipitates or clusters with a maximum diameter of 8 nm or less are dispersed in the crystal grains with a number density of 1×1016 to 1×1019 pieces/cm3 and soft crystal grains B in which precipitates or clusters with a maximum diameter of 8 nm or less are dispersed in the crystal grains with a number density of 1×1015 pieces/cm3 or less are contained, and the volume % of the hard crystal grains A/(the volume % of the hard crystal grains A +the volume % of the soft crystal grains B) is 0.1 to 0.9.Type: ApplicationFiled: August 4, 2017Publication date: August 1, 2019Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kohichi SANO, Makoto UNO, Ryoichi NISHIYAMA, Yuji YAMAGUCHI, Natsuko SUGIURA, Masahiro NAKATA
-
Publication number: 20190226061Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 30 to 95%, and bainite: 5 to 70%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. An average aspect ratio of ellipses equivalent to the crystal grains is 5 or less. An average distribution density of the total of Ti-based carbides and Nb-based carbides each having a grain size of 20 nm or more on ferrite grain boundaries is 10 carbides/?m or less.Type: ApplicationFiled: August 4, 2017Publication date: July 25, 2019Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kohichi SANO, Makoto UNO, Ryoichi NISHIYAMA, Yuji YAMAGUCHI, Natsuko SUGIURA, Masahiro NAKATA